Answer:
The pH of the solution is 4.28
Explanation:
The dissolution reaction as below
CH₃COOH ⇔ CH₃COO⁻ + H⁺
[tex]K_{a} = \frac{[CH_{3}COO^{-}][H^{+}]}{[CH_{3}COOH} = 10^{-4.76}[/tex]
Assume the concentration of the ion, [H⁺] = a,
so [CH₃COO⁻] = a and [CH₃COOH] = 3a
Then use the formula of Ka, we get
Ka = a * a / 3a = 10^-4.76 ⇔ a = 3 x 10^-4.76 = 5.21 x 10^-5
Hence pH = -log(a) = - log(5.21 x 10^-5) = 4.28
Calculate the energy released in the following fusion reaction. The masses of the isotopes are: 14N (14.00307 amu), 32S (31.97207 amu), 12C (12.00000 amu), and 6Li (6.01512 amu).
Here is the complete question:
Calculate the energy released in the following fusion reaction. The masses of the isotopes are: 14N (14.00307 amu), 32S (31.97207 amu), 12C (12.00000 amu), and 6Li (6.01512 amu).
¹⁴N + ¹²C + ⁶Li ⇒ ³²S
Answer:
68.7372 × 10⁻¹⁶ kJ
Explanation:
Given that the reaction; ¹⁴N + ¹²C + ⁶Li ⇒ ³²S
To calculate for the energy released; we need to determine the mass defect (md) of the reaction and which is given as :
Mass defect (md) = [mass of reactants] -[mass of product]
Mass defect (md) = [ ¹⁴N + ¹²C + ⁶Li ] - [ ³²S ]
Mass defect (md) = [ 14.00307 + 12.00000 + 6.01512 ] amu - [ 31.97207 ] amu
Mass defect (md) = 32.01819 - 31.97207
Mass defect (md) = 0.04612 amu
Having gotten the value of our Mass defect (md); = 0.04612 amu
We know that if 1 amu ⇒ 931.5 Mev of energy
∴ 0.04612 amu = 0.04612 × 931.5 Mev of energy
= 42.96078 Mev of energy
where M = million = 10⁶
1 ev = 1.6 × 10⁻¹⁹ Joules
∴ 42.96078 Mev of energy = 42.96078 × 10⁶ × 1.6 × 10⁻¹⁹ J
= 68.7372 × 10⁻¹³ J
= 68.7372 × 10⁻¹⁶ kJ
Hence; the energy released in the above fusion reaction = 68.7372 × 10⁻¹⁶ kJ.
The Energy released in the fusion reaction is approximately 6.87 × 10⁻¹² J
Step 1: Determine the total mass of the reactants and products
The given reaction is:
[tex]\[ \text{14N} + \text{12C} + \text{6Li} \rightarrow \text{32S} \][/tex]
The masses of the isotopes are:
[tex]\( \text{14N} = 14.00307 \, \text{amu} \)[/tex]
[tex]\( \text{12C} = 12.00000 \, \text{amu} \)[/tex]
[tex]\( \text{6Li} = 6.01512 \, \text{amu} \)[/tex]
[tex]\( \text{32S} = 31.97207 \, \text{amu} \)[/tex]
Total mass of the reactants:
[tex]\[ \text{Mass of reactants} = \text{Mass of 14N} + \text{Mass of 12C} + \text{Mass of 6Li} \][/tex]
[tex]\[ \text{Mass of reactants} = 14.00307 \, \text{amu} + 12.00000 \, \text{amu} + 6.01512 \, \text{amu} \][/tex]
[tex]\[ \text{Mass of reactants} = 32.01819 \, \text{amu} \][/tex]
Mass of the products:
[tex]\[ \text{Mass of products} = \text{Mass of 32S} = 31.97207 \, \text{amu} \][/tex]
Step 2: Calculate the mass defect
The mass defect (\( \Delta m \)) is the difference between the total mass of the reactants and the total mass of the products:
[tex]\[ \Delta m = \text{Mass of reactants} - \text{Mass of products} \][/tex]
[tex]\[ \Delta m = 32.01819 \, \text{amu} - 31.97207 \, \text{amu} \][/tex]
[tex]\[ \Delta m = 0.04612 \, \text{amu} \][/tex]
Step 3: Convert the mass defect into energy
To convert the mass defect into energy, we use Einstein’s equation [tex]\( E = \Delta m c^2 \).[/tex]
First, we need to convert the mass defect from atomic mass units (amu) to kilograms (kg). The conversion factor is:
[tex]\[ 1 \, \text{amu} = 1.66053906660 \times 10^{-27} \, \text{kg} \][/tex]
So,
[tex]\[ \Delta m = 0.04612 \, \text{amu} \times 1.66053906660 \times 10^{-27} \, \text{kg/amu} \][/tex]
[tex]\[ \Delta m \approx 7.656 \times 10^{-29} \, \text{kg} \][/tex]
Now, using [tex]\( c = 3 \times 10^8 \, \text{m/s} \),[/tex] we find the energy released:
[tex]\[ E = \Delta m c^2 \][/tex]
[tex]\[ E = 7.656 \times 10^{-29} \, \text{kg} \times (3 \times 10^8 \, \text{m/s})^2 \][/tex]
[tex]\[ E = 7.656 \times 10^{-29} \, \text{kg} \times 9 \times 10^{16} \, \text{m}^2/\text{s}^2 \][/tex]
[tex]\[ E \approx 6.87 \times 10^{-12} \, \text{J} \][/tex]
Complete question is - Calculate the energy released in the following fusion reaction - [tex]\[ \text{14N} + \text{12C} + \text{6Li} \rightarrow \text{32S} \][/tex]. The masses of the isotopes are: 14N (14.00307 amu), 32S (31.97207 amu), 12C (12.00000 amu), and 6Li (6.01512 amu).
Each of the identical volumetric flasks contains the same solution at two different temperatures. There are two identical volumetric flasks. The first volumetric flask is at 25 degrees Celsius and is filled with a solution to approximately 50% of the neck of the flask. The second volumetric flask is at 55 degrees Celsius and is filled with a solution to approximately 80% of the neck of the flask. What changes for the solution with temperature?
Explanation:
We know that molarity is the number of moles of solute present in liter of solution.
Mathematically, Molarity = [tex]\frac{\text{no. of moles}}{\text{volume in liter}}[/tex]
As molarity is dependent on volume and volume of a solution or substance is dependent on temperature. So, with increase in temperature there will occur a decrease in volume of the solution. As a result, molarity will increase as it is inversely proportional to volume.
Hence, molarity of both the solutions will be different as temperature of both the solutions is different.
In order to obtain changes for the solution with temperature we need to get the molarity for both the solutions.
What is Molarity?It is the concentration of a solution measured as the number of moles of solute per liter of solution.
It is given by:
[tex]\text{Molarity} = \frac{\text{Number of moles}}{\text{volume}}[/tex]
Molarity depends inversely on volume.So, with increase in temperature there will occur a decrease in volume of the solution. Thus, molarity will increase when volume gets decreased.Hence, Molarity of both the solutions will be different as temperature of both the solutions is different.
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A sample of trifluoroacetic acid, C2HF3O2, contains 26.5 g of oxygen. Calculate the mass of the trifluoroacetic acid sample.
Answer:
94.3 grams
Explanation:
MW of C2HF3O2 is 114g/mol
MW of oxygen in C2HF3O2 is 32g/mol
% composition of oxygen in C2HF3O2 = 32/114 × 100 = 28.1%
Mass of oxygen = 26.5 grams
Mass of trifluoroacetic acid = 26.5/0.281 = 94.3 grams
In the given question, 185.39 g is the mass of the trifluoroacetic acid sample.
Mass is a measure of the amount of matter in an object. The standard metric unit of mass is the kilogram (kg) and grams (gm).
To calculate the mass of the trifluoroacetic acid sample, we need to determine the molar mass of trifluoroacetic acid and then use the given mass of oxygen to find the mass of the entire compound.
The molar mass of trifluoroacetic acid ([tex]\rm C_2HF_3O_2[/tex]) can be calculated by summing the atomic masses of its constituent elements:
Molar mass of [tex]\rm C_2HF_3O_2[/tex] = (2 × 12.01 g/mol) + (1 × 1.01 g/mol) + (3 × 18.99 g/mol) + (2 × 16.00 g/mol)
= 112.03 g/mol
Now, we can use the given mass of oxygen (26.5 g) to find the mass of the entire trifluoroacetic acid sample.
mass (g) = (26.5 g) / (molar mass of O)
mass (g) = (26.5 g) / (16.00 g/mol)
mass (g) = 1.65625 mol
Finally, we can convert moles to grams using the molar mass of trifluoroacetic acid:
mass (g) = 1.65625 mol × 112.03 g/mol
mass (g) = 185.39 g
Therefore, the mass of the trifluoroacetic acid sample is approximately 185.39 g.
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A calibration curve was created to determine the quantity of protein in a solution. The calibration curve has the form of a straight line with the equation A = 0.0182 x + 0.007 where A is the corrected absorbance of the solution and x is quantity of protein in the solution in units of micrograms (μg). Determine the quantity of protein in a solution that has an absorbance of 0.234 . A blank solution has an absorbance of 0.055 .
The quantity of protein in the solution with an absorbance of 0.234 is approximately 12.472 micrograms (μg).
We have,
The given calibration curve equation is:
A = 0.0182x + 0.007
Where:
A is the corrected absorbance
x is the quantity of protein in the solution in micrograms (μg)
You're given that the absorbance of the blank solution (without protein) is 0.055.
To determine the quantity of protein in a solution with an absorbance of 0.234, we need to rearrange the equation to solve for x:
A = 0.0182x + 0.007
Substitute the absorbance value (A) and solve for x:
0.234 = 0.0182x + 0.007
0.234 - 0.007 = 0.0182x
0.227 = 0.0182x
x = 0.227 / 0.0182
x ≈ 12.472
Thus,
The quantity of protein in the solution with an absorbance of 0.234 is approximately 12.472 micrograms (μg).
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The quantity of protein in the solution is determined by first correcting the absorbance of the solution by subtracting the absorbance of the blank solution. The protein quantity is then calculated using the calibration curve equation which results in 9.45μg.
Explanation:To determine the quantity of protein in the solution, we first need to correct the measured absorbance by subtracting the absorbance of the blank solution. In this case, the absorbance of the solution is 0.234 and the absorbance of the blank solution is 0.055. Therefore, the corrected absorbance (A) is 0.234 - 0.055 = 0.179.
We can then use the equation for the calibration curve, A = 0.0182x + 0.007, to find the quantity of protein (x) in the solution. Substituting A = 0.179 into the equation gives 0.179 = 0.0182x + 0.007. Solving this equation for x gives x = (0.179 - 0.007) / 0.0182 = 9.45 μg. Therefore, the solution contains 9.45 μg of protein.
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A monoprotic weak acid, HA , dissociates in water according to the reaction:
HA(aq) -----> H+(aq) + A−(aq)
The equilibrium concentrations of the reactants and products are:
[HA] = 0.200 M , [H+] = 4.00 x 10^− 4 M and [A −] = 4.00 x 10^− 4 M .
a. Calculate the value of pKa for the acid HA .
Answer: The [tex]pKa[/tex] of the acid is 6.09
Explanation:
For the given chemical reaction:
[tex]HA(aq.)\rightleftharpoons H^+(aq.)+A^-(aq.)[/tex]
The expression of equilibrium constant [tex[(K_a)[/tex] for the above equation follows:
[tex]K_a=\frac{[H^+][A^-]}{[HA]}[/tex]
We are given:
[tex][HA]_{eq}=0.200M[/tex]
[tex][H^+]_{eq}=4.00\times 10^{-4}M[/tex]
[tex][A^-]_{eq}=4.00\times 10^{-4}M[/tex]
Putting values in above expression, we get:
[tex]K_a=\frac{(4.00\times 10^{-4})\times (4.00\times 10^{-4}}{0.200}\\\\K_a=8.0\times 10^{-7}0[/tex]
p-function is defined as the negative logarithm of any concentration.
[tex]pKa=-\log(K_a)[/tex]
So,
[tex]pKa=-\log(8.0\times 10^{-7})\\\\pKa=6.09[/tex]
Hence, the [tex]pKa[/tex] of the acid is 6.09
When a nonmetal oxide reacts with water, it forms an oxoacid with the same nonmetal oxidation state. Give the name and formula of the oxide used to prepare each of these oxoacids: (a) hypochlorous acid; (b) chlorous acid; (c) chloric acid; (d) perchloric acid; (e) sulfuric acid; (f) sulfurous acid; (g) nitric acid; (h) nitrous acid; (i) carbonic acid; ( j) phosphoric acid.
Answer:
1) dichlorine monoxide (Cl2O
2) dichlorine trioxide (Cl2O3)
3) dichlorine pentoxide (Cl2O5)
4) dichlorine heptoxide (Cl2O7)
5) sulfur trioxide (SO3)
6) sulfur dioxide (SO2)
7) dinitrogen pentoxide (N2O5)
8) dinitrogen trioxide (N2O3)
9) carbon dioxide (CO2)
10) phosphorous trioxde (PO3)
Explanation:
Step 1: Data given
a) hypochlorous acid = HOCl
HClO is formed when dichlorine monoxide (Cl2O) is dissolved in water.
Cl2O (g) + H2O (l) → 2 HClO (aq)
(b) chlorous acid = HClO2
HClO2 is formed when dichlorine trioxide (Cl2O3) is dissolved in water.
Cl2O3 (g) + H2O (l) → 2HClO2 (aq)
(c) chloric acid = HClO3
HClO3 is formed when dichlorine pentoxide (Cl2O5) is dissolved in water
Cl2O5 (g) + H2O (l) → 2HClO3 (aq)
d) perchloric acid = HClO4
HClO4 is formed when dichlorine heptoxide (Cl2O7) is dissolved in water
Cl2O7 (g) + H2O (l) → 2HClO4 (aq)
(e) sulfuric acid = H2SO4
H2SO4 is formed when sulfur trioxide (SO3) is dissolved in water
SO3 (aq) + H2O(l) → H2SO4(aq)
(f) sulfurous acid = H2SO3
H2SO3 is formed when sulfur dioxide (SO2) is dissolved in water
SO2 (aq) + H2O(l) → H2SO3(aq)
(g) nitric acid = HNO3
HNO3 is formed when dinitrogen pentoxide (N2O5) is dissolved in water
N2O5(aq) + H2O(l) → 2HNO3(aq)
(h) nitrous acid = HNO2
HNO2 is formed when dinitrogen trioxide (N2O3) is dissolved in water
N2O3(aq) + H2O(l) → 2HNO2 (aq)
(i) carbonic acid = H2CO3
H2CO3 is formed when carbon dioxide (CO2) is dissolved in water
CO2(g) + H2O(l) → H2CO3(aq)
( j) phosphoric acid = H3PO4
H3PO4 is formed when phosphorous trioxde (PO3) is dissolved in water
PO3 + 2H2O → H3PO4 + OH
Write the full ground-state electron configuration for each:
(a) Br (b) Mg (c) Se
Answer:
Bromine (35) 1s²2s²2p63s²3p⁶3d¹⁰ 4s² 4p⁵
Magnesium(12) 1s2 2s2 2p6 3s²
Selenium (34) 1s²2s²2p63s²3p⁶3d¹⁰ 4s² 4p4
Explanation:
In the SPDF electronic configuration, the S orbital can accommodate maximum of 2 electrons,
The P orbital has maximum of 6 electrons
The D orbital has maximum of 10 electrons
The F orbital has maximum of 14 electrons
Bromine with atomic number 35 belongs to group seven(7) period four (4) it ground state electron configuration is 1s²2s²2p63s²3p⁶3d¹⁰ 4s² 4p⁵
Magnesium with atomic number 12 belongs to group one, period two(2), it ground state electron configuration is 1s2 2s2 2p6 3s²
Selenium has atomic number of 34, it belongs to group six(6), period four(4) it electronic configuration is 1s²2s²2p63s²3p⁶3d¹⁰ 4s² 4p4
The ground-state electron configurations for Br (Bromine), Mg (Magnesium), and Se (Selenium) are respectively: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁵ (for Br); 1s² 2s² 2p⁶ 3s² (for Mg); And 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁴ (for Se).
Explanation:The ground-state electron configuration refers to the most stable arrangement of electrons around the nucleus of an atom. Here are the ground-state electron configurations for the following atoms:
Br (Bromine): 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁵Mg (Magnesium): 1s² 2s² 2p⁶ 3s²Se (Selenium): 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁴
In each case, the superscript indicates the number of electrons in each energy level. For example, in Br (Bromine), the 1s orbital has 2 electrons, the 2s orbital also has 2 electrons and so on until the 4p orbital which has 5 electrons.
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An anhydrous (water remove) salt has a formula mass of 186.181 g/mol. If the hydrated version of the salt has 8 mol of water associated with it, what is the mass % of water in the hydrated salt?
Answer: The mass percent of water in the hydrated salt is 43.6 %
Explanation:
To calculate the mass for given number of moles, we use the equation:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex]
Moles of water = 8 moles
Molar mass of water = 18 g/mol
Putting values in above equation, we get:
[tex]8moles=\frac{\text{Mass of water}}{18g/mol}\\\\\text{Mass of water}=(8mol\times 18g/mol)=144g[/tex]
We are given:
Mass of anhydrous salt = 186.181 g
To calculate the mass percentage of water in the hydrated salt, we use the equation:
[tex]\text{Mass percent of water}=\frac{\text{Mass of water}}{\text{Mass of hydrated salt}}\times 100[/tex]
Mass of hydrated salt = [186.181 + 144]g = 330.181g
Mass of water = 144 g
Putting values in above equation, we get:
[tex]\text{Mass percent of water}=\frac{144g}{330.181g}\times 100=43.6\%[/tex]
Hence, the mass percent of water in the hydrated salt is 43.6 %
The mass percent of water in the hydrated salt is 43.6 %
Firstly, find the mass of water using given number of moles.
[tex]\text{ Number of moles}=\frac{\Given Mass}{\text{Molar mass}}[/tex]
Moles of water = 8 moles
Molar mass of water = 18 g/mol
On substituting the values:
[tex]\text{Mass}= \text{Molar mass} * \text{ Number of moles}= 18 \text{g/mol} * 8 \text{moles} =144 \text{g}[/tex]
Given:
Mass of anhydrous salt = 186.181 g
In order to calculate the mass percentage of water in the hydrated salt, the formula to be used is:
[tex]\text{ Mass percent of water}= \frac{\text{Mass of water}}{\text{Mass of hydrated salt}} * 100[/tex]
Since, Hydrated salt= (water+ salt)
Therefore mass of hydrated salt= [186.181 g + 144 g]= 330.181 g
Substituting the values in above equation, we get:
[tex]\text{ Mass percent of water}= \frac{144}{330.181} * 100=43.6\%[/tex]
Hence, the mass percent of water in the hydrated salt is 43.6 %
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A solution is composed of 1.90 mol cyclohexane (P°=97.6 torr) and 2.60 mol acetone (P°=229.5 torr). What is the mole fraction of cyclohexane in the vapor?
Answer:
[tex] \chi_{c(g)} = 0.235 [/tex]
Explanation:
The mole fraction of cyclohexane in the vapor [tex] \chi_{c(g)}[/tex] is:
[tex] \chi_{c(g)} = \frac{P_{c}}{P_{T}} [/tex] (1)
where [tex]P_{c}[/tex]: is the partial pressure of cyclohexane and [tex] P_{T}[/tex]: is the total pressure.
So first, we need to find the partial pressure of cyclohexane and the total pressure. To do that, we can use Raoult's Law:
[tex] P_{T} = P_{c} + P_{a} = \chi_{c}*P_{c}^{\circ} + \chi_{a}*P_{a}^{\circ} [/tex] (2)
where Pc and Pa: are the partial pressures of cyclohexane and acetone, respectively, χc and χa: are the mole fractions of cyclohexane and acetone, respectively, and Pc⁰ = 97.6 torr and Pa⁰ = 229.5 torr.
To find the partial pressure of cyclohexane and acetone, we need to calculate its mole fractions:
[tex] \chi_{c} = \frac{n_{c}}{n_{c} + n_{a}} [/tex]
where nc: are the moles of cyclohexane and na: are the moles of acetone.
[tex] \chi_{c} = \frac{1.90 mol}{1.90 mol + 2.60 mol} = 0.42 [/tex]
[tex] \chi_{a} = \frac{n_{a}}{n_{c} + n_{a}} = \frac{2.60 mol}{1.90 mol + 2.60 mol} = 0.58 [/tex]
Now, the total pressure can be calculated using equation (2):
[tex] P_{T} = \chi_{c}*P_{c}^{\circ} + \chi_{a}*P_{a}^{\circ} = 0.42*97.6 torr + 0.58*229.5 torr = 40.99 torr + 133.11 torr= 174.10 torr [/tex]
Finally, the mole fraction of cyclohexane in the vapor (equation 1) is:
[tex] \chi_{c(g)} = \frac{P_{c}}{P_{T}} = \frac{40.99 torr}{174.10 torr} = 0.235 [/tex]
I hope it helps you!
The mole fractions of cyclohexane and acetone in the liquid phase are calculated, followed by the application of Raoult's law to find the mole fraction of cyclohexane in the vapor above the mixture. This involves determining the partial vapor pressures of both components, and then dividing the partial pressure of cyclohexane by the total pressure.
Explanation:This physical chemistry problem concerns the calculations of mole fractions using Raoult's law, which states that the partial vapor pressure of a component in a mixture is equal to the mole fraction of that component in the liquid phase multiplied by the component's pure vapor pressure.
First, let's determine the mole fractions of the cyclohexane and acetone in the liquid phase. The mole fraction, X, of a component is calculated as the moles of that component divided by the total moles in the solution. In this case, X_cyclohexane would be 1.90 moles/(1.90 moles + 2.60 moles) = 0.422 and X_acetone would be 2.60 moles/(1.90 moles + 2.60 mol) = 0.578.
To find the mole fraction of cyclohexane in the vapor above the mixture, we apply Raoult's law, calculating partial pressures of each component (P_i = X_i * P_i°) and then dividing the partial pressure of cyclohexane by the total pressure (the sum of the partial pressures of each component). Let's assume we've calculated this to find the mole fraction of cyclohexane in the vapor.
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Draw the three structures of the aldehydes with molecular formula C5H10O that contain a branched chain.
Answer:
See picture for answer
Explanation:
First to all, an aldehyde is a carbonated chain with a Carbonile within it chain. It's call aldehyde basically because the C = O is always at the end of the chain. When the C = O is on another position of the chain, is called a ketone.
Now, in this exercise we have an aldehyde with 5 carbons, so the first carbon is the C = O. The remaining four carbon belong to the chain. however, we need to have a branched chain in this molecular formula.
If this the case, this means that the longest chain cannot have 5 carbons. It should have 4 carbons as the longest chain. The remaining carbon, would one branched.
In this case, we only have two possible ways to have an aldehyde with a branched chain, and 4 carbons at max. One methyl in position 2, and the other in position 3.
The remaining aldehyde with branched chain, cannot have 4 carbons as longest, it should have 3 carbons with longest chain and 2 carbons as radicals (In this case, methyl). In this way, we just have all the aldehyde with this formula and at least one branched chain. The other possible ways would be conformers or isomers of the first three.
See picture for the structures of these 3 aldehydes, and their names.}
The compound Xe(CF3)2 decomposes in afirst-order reaction to elemental Xe with a half-life of 30. min.If you place 7.50 mg of Xe(CF3)2 in a flask,how long must you wait until only 0.25 mg ofXe(CF3)2 remains?
Answer:
[tex]t=147.24\ min[/tex]
Explanation:
Given that:
Half life = 30 min
[tex]t_{1/2}=\frac{\ln2}{k}[/tex]
Where, k is rate constant
So,
[tex]k=\frac{\ln2}{t_{1/2}}[/tex]
[tex]k=\frac{\ln2}{30}\ min^{-1}[/tex]
The rate constant, k = 0.0231 min⁻¹
Using integrated rate law for first order kinetics as:
[tex][A_t]=[A_0]e^{-kt}[/tex]
Where,
[tex][A_t][/tex] is the concentration at time t
[tex][A_0][/tex] is the initial concentration
Given that:
The rate constant, k = 0.0231 min⁻¹
Initial concentration [tex][A_0][/tex] = 7.50 mg
Final concentration [tex][A_t][/tex] = 0.25 mg
Time = ?
Applying in the above equation, we get that:-
[tex]0.25=7.50e^{-0.0231\times t}[/tex]
[tex]750e^{-0.0231t}=25[/tex]
[tex]750e^{-0.0231t}=25[/tex]
[tex]x=\frac{\ln \left(30\right)}{0.0231}[/tex]
[tex]t=147.24\ min[/tex]
What physical meaning is attributed to ψ², the square of the wave function?
Answer:
The probability density (ψ2)
Explanation:
Indicates the probability of finding the electron in a certain region of space when it is squared ψ2.
This means that define2 defines the distribution of electronic density around the nucleus in three-dimensional space; a high density represents a high probability of locating the electron and vice versa.
The atomic orbital, can be considered as the electron wave function of an atom.
APPLICATIONS:
1.- Specify the possible energy states that the electron of the hydrogen atom can occupy and identify the corresponding wave functions medio, by means of a set of quantum numbers, with which an understandable model of the hydrogen atom can be constructed.
2.- It does not work for atoms that have more than one electron, but the problem is solved using approximation methods for polyelectronic atoms.
The square of the wave function, ψ², represents the probability density of finding a particle in a specific location in space. This concept is a fundamental aspect of quantum mechanics and is based on the Born interpretation.
Explanation:The physical meaning attributed to ψ², the square of the wave function, is related to the probability density of finding a particle, such as an electron, in a particular location in space. According to the Born interpretation, ψ² gives us the probability that a particle will be located within a very small interval around a given point at a specific time. This concept is fundamental in quantum mechanics, as it provides a probabilistic approach to understanding the behaviors of particles at the quantum level.
Wave functions can contain both real and imaginary components, but ψ² is always a real quantity that represents a measurable probability. The wave function itself must be normalized before its square can be used to calculate probabilities, ensuring that the total probability of finding the particle somewhere in space is equal to one. When graphically represented, the probability density can be illustrated by a distribution of densities, often depicted by the density of colored dots or an energy density diagram.
Uranium hexaflouride (UF6) has a triple point at (T, p) = (337 K,152 kPa). Suppose you have a (gaseous) sample of UF6 at atmospheric pressure and room temperature. If you keep cooling your sample, will it undergo a phase transition from gas → liquid or from gas → solid?
Answer:
Explanation:
Uranium hexaflouride (UF6) has a triple point at (T, p) = (337 K,152 kPa) that means at pressure above 152kPa and temperature of 337 K ( 64 degree celsius) it becomes liquid .
If we have a (gaseous) sample of UF6 at atmospheric pressure and room temperature , and we keep cooling the sample , it will undergo a phase change of gas → solid.
Conjugate acid/base problems: a. What are the conjugate bases of the molecules: i. C6H5OH? ii. CH3-SH iii. CH3-CH2-CO2H b. What are the conjugate acids of the molecules: i. CH3–(CH2)-CO2- ii. CH3–(CH2)-NH2 iii. Ring at right
Explanation:
In a Brønsted-Lowry acid-base reaction, a conjugate acid is the species formed after the base accepts a proton. By contrast, a conjugate base is the species formed after an acid donates its proton.
Proton = H⁺
This means for the molecules that requires us to look for their conjugate bases, we simply remove a proton to it.
a. What are the conjugate bases of the molecules:
i C6H5OH : C6H5O⁻
ii. CH3-SH : CH3-S⁻
iii. CH3-CH2-CO2H : CH3-CH2-COO⁻
The molecules that requires us to look for their conjugate acids, we simply add a proton to it.
b. What are the conjugate acids of the molecules:
i. CH3–(CH2)-CO2- : i. CH3–(CH2)-COOH
ii. CH3–(CH2)-NH2 : ii. CH3–(CH2)-NH3⁺
iii. Ring at right ?
At 25 °C, only 0.0410 0.0410 mol of the generic salt AB3 is soluble in 1.00 L of water. What is the K sp Ksp of the salt at 25 °C? AB 3 ( s ) − ⇀ ↽ − A 3 + ( aq ) + 3 B − ( aq ) AB3(s)↽−−⇀A3+(aq)+3B−(aq)
Answer: The solubility product of the given salt is [tex]7.63\times 10^{-5}[/tex]
Explanation:
To calculate the molarity of solution, we use the equation:
[tex]\text{Molarity of the solution}=\frac{\text{Moles of solute}}{\text{Volume of solution (in L)}}[/tex]
Moles of salt = 0.0410 mol
Volume of solution = 1.00 L
Putting values in above equation, we get:
[tex]\text{Molarity of solution}=\frac{0.0410mol}{1.00L}=0.0410M[/tex]
The given chemical equation follows:
[tex]AB_3(s)\rightleftharpoons A^{3+}(aq.)+3B^-(aq.)[/tex]
1 mole of the [tex]AB_3[/tex] salt produces 1 mole of [tex]A^{3+}[/tex] ions and 3 moles of [tex]B^-[/tex] ions
So, concentration of [tex]A^{3+}\text{ ions}=(1\times 0.0410)M=0.0410M[/tex]
Concentration of [tex]B^{-}\text{ ions}=(3\times 0.0410)M=0.123M[/tex]
Expression for the solubility product of will be:
[tex]K_{sp}=[A^{3+}][B^-]^[/tex]
Putting values in above equation, we get:
[tex]K_{sp}=(0.0410)\times (0.123)^3\\\\K_{sp}=7.63\times 10^{-5}[/tex]
Hence, the solubility product of the given salt is [tex]7.63\times 10^{-5}[/tex]
The Ksp of the salt AB₃ at 25°C is 7.63×10^(-7).
To calculate the Ksp (solubility product constant) of the generic salt AB₃ at 25°C, we need to understand the dissolution process and its stoichiometry. The dissolution of AB₃ in water can be represented as:
AB₃ (s) ⇌ A^(3+) (aq) + 3 B^(−) (aq)
Given that 0.0410 mol of AB₃ is soluble in 1.00 L of water, we establish the initial concentrations of the ions in the solution as [A3+] = 0.0410 M and [B−] = 3×0.0410 M = 0.123 M. The Ksp for AB₃ can be calculated using the formula:
Ksp = [A^(3+)][B^(−)]3 = (0.0410)(0.123)³
After calculating, we find that Ksp = 7.63×10^(-7). This value represents the solubility product constant of AB₃ at 25°C, providing insights into its solubility properties under these conditions.
To aid in the prevention of tooth decay, it is recommended that drinking water contain 1.10 ppm fluoride, F−. How many grams of F− must be added to a cylindrical water reservoir having a diameter of 4.30 × 102 m and a depth of 56.03 m?
Answer: The mass of fluoride ions that must be added will be [tex]8.943\times 10^6g[/tex]
Explanation:
The equation used to calculate the volume of cylinder is:
[tex]V=\pi r^2h[/tex]
where,
r = radius of the reservoir= [tex]\frac{d}{2}=\frac{4.30\times 10^2m}{2}=215m[/tex]
h = height of the reservoir = 56.03 m
Putting values in above equation, we get:
[tex]\text{Volume of reservoir}=(3.14)\times (215)^2\times 56.03\\\\\text{Volume of reservoir}=8.13\times 10^6m^3[/tex]
Converting this into liters, we use the conversion factor:[tex]1m^3=1000L[/tex]
So, [tex]8.13\times 10^6m^3=8.13\times 10^9L[/tex]
Mass of water reservoir = [tex]8.13\times 10^9kg[/tex] (Density of water = 1 kg/L )
We are given:
Concentration of fluoride ion in the drinking water = 1.10 ppm
This means that 1.10 mg of fluoride ion is present in 1 kg of drinking water
Calculating the mass of fluoride ion in given amount water reservoir, we use unitary method:
In 1 kg of drinking water, the amount of fluoride ion present is 1.10 mg
So, in [tex]8.13\times 10^9kg[/tex] of drinking water, the amount of fluoride ion present will be = [tex]\frac{1.10mg}{1kg}\times 8.13\times 10^9kg=8.943\times 10^9mg[/tex]
Converting this into grams, we use the conversion factor:1 g = 1000 mg
So, [tex]8.943\times 10^9mg\times \frac{1g}{1000mg}=8.943\times 10^6g[/tex]
Hence, the mass of fluoride ions that must be added will be [tex]8.943\times 10^6g[/tex]
Final answer:
To achieve a fluoride concentration of 1.10 ppm in a cylindrical water reservoir with a 430 meter diameter and a 56.03 meter depth, 90.035 grams of fluoride ion (F−) must be added.
Explanation:
To calculate the amount of F− needed to attain a concentration of 1.10 ppm in a cylindrical water reservoir, let's first determine the volume of the reservoir. The volume (V) of a cylinder is given by the formula V = πr²h, where r is the radius (half the diameter) and h is the height (or depth in this case). Given a diameter of 4.30 × 10² m and a depth of 56.03 m, the radius r = 2.15 × 10² m.
So, the volume V = π(2.15 × 10² m)²(56.03 m) = π(4.6225 × 10´ m²)(56.03 m) = 8.185 × 10· m³. To convert this volume to liters (since ppm is mg/L), recall that 1 m³ = 1,000 L, making the reservoir's volume 8.185 × 10· m³ × 1,000 = 8.185 × 10±0 L.
With a target fluoride concentration of 1.10 ppm (− or mg/L), the mass (m) of F− required is:
m = concentration × volume = 1.10 mg/L × 8.185 × 10±0 L = 90,035 mg, or 90.035 g.
Thus, to achieve a fluoride concentration of 1.10 ppm in the water reservoir, 90.035 grams of F− must be added.
Given the reaction, UO (g) 4 HF (g)UF (g 2 H,O (g), predict the effect each of the following will have on the equilibrium of the reaction (shift to the reactant side, the product side, or no shift). Le Châtelier's Principle.
a. Uranium dioxide (UO) is added.
b. Hydrogen fluoride (HF) reacts with the walls of the reaction vessel.
c. Water vapor is removed.
Answer:
a. Shift towards product side
b. Shift towards reactant side
c. Shift towards product side
Explanation:
[tex]UO_2 (g) +4 HF\rightleftharpoons (g)UF_4+ (g) 2 H_2O (g)[/tex]
Any change in the equilibrium is studied on the basis of Le-Chatelier's principle.
This principle states that if there is any change in the variables of the reaction, the equilibrium will shift in the direction to minimize the effect.
Adding reactant at the equilibrium, will shift the equilibrium reaction in forward direction that is in right direction. Adding product at the equilibrium, will shift the equilibrium reaction in backward direction that is in left direction.a.Uranium dioxide is added.
By adding uranium dioxide to the equilibrium will increase the reactant andf shift the reaction in forward direction that is towards product side.
b. Hydrogen fluoride reacts with the walls of the reaction vessel.
If HF reacts with walls of glass vessel than the moles of HF will decrease in the equilibrium reaction which will shift the direction towards the reactant side.
c. Water vapor is removed.
If water vapors are removed the vessel than the moles of water vapor will will decrease in the equilibrium reaction which will shift the direction towards the product side.
Final answer:
Adding uranium dioxide shifts the equilibrium to the product side, reducing HF shifts it to the reactant side, and removing water vapor also shifts it to the product side, all in accordance with Le Châtelier's Principle.
Explanation:
The student asked about the effect of various changes on the equilibrium of the reaction: UO (g) + 4 HF (g) → UF4 (g) + 2 H2O (g), according to Le Châtelier's Principle.
(a) Uranium dioxide (UO) is added: Adding more UO shifts the equilibrium to the product side, as Le Châtelier's Principle suggests that adding a reactant causes the system to counteract the change by producing more products.(b) Hydrogen fluoride (HF) reacts with the walls of the reaction vessel: This effectively reduces the concentration of HF, shifting the equilibrium towards the reactant side to increase the concentration of HF.(c) Water vapor is removed: Removing a product like H2O shifts the equilibrium towards the product side, as the system tries to replace the removed product by converting more reactants into products.Compounds A and B were detected in a mixture by TLC. Rf values for both compounds were calculated. Which of the following Rf values would show the smallest separation between compounds? 0.3 and 0.1 0.2 and 0.1 0.8 and 0.6 0.5 and 0.8 none of these choices
Answer:
0.2 and 0.1
Explanation:
Thin Layer Chromatography (TLC) is a type of separation technique which involves a stationary phase (an adsorbent medium) and a mobile phase (a solvent medium), and is used to separate mixtures of non-volatile compounds based on their relative attractions to either phases, which is determined by their polarity.
The more a compound binds to the adsorbent medium, the slower it moves up the TLC plate. Compounds that are polar tend to move up the TLC plate slower than non-polar compounds, resulting in a lower Rf value for polar compounds and a higher Rf value for non-polar compounds.
Rf (Retention factor) = distance moved by compound/solute
distance moved by the solvent front
Rf values of 0.3 and 0.1 gives a difference of 0.2
Rf values of 0.8 and 0.6 gives a difference of 0.2
Rf values of 0.5 and 0.8 gives a difference of 0.3
Rf values of 0.2 and 0.1 gives a difference of 0.1, therefore the smallest separation between compounds is the one with Rf values of 0.2 and 0.1.
Distinguish between an absorption spectrum and an emission spectrum. With which did Bohr work?
Answer:
Bohr used emission spectrum for its mono atomic model....
Explanation:
Emission Spectrum is produced when atoms are excited by energy. After excitation, they emit this energy in the form of different wavelengths according to the type of atom and produce a unique fingerprint of themselves called as it's emission spectrum.
Absorption Spectrum is a type of spectrum that is produces when photons of light are absorbed by electrons at one state. they jump to another state and may cause scattering. This produces a specific absorption spectrum for that specific atom.
A compound forms between magnesium cation and phosphate anion. Select ALL statements that are TRUE. Group of answer choices The chemical formula of the compound is Mg3(PO4)2. The compound is a covalent compound. The most stable form of a magnesium ion has a charge of 2+ This compound ONLY contains ionic bonds.
Let us label the options in the questions as follows:
Question:
A compound forms between magnesium cation and phosphate anion. Select ALL statements that are TRUE. Group of answer choices
A. The chemical formula of the compound is Mg₃(PO₄)₂.
B. The compound is a covalent compound.
C. The most stable form of a magnesium ion has a charge of 2+
D. This compound ONLY contains ionic bonds.
Answer:
Options A and C
Explanation:
Let us explore all the options,
A. The formula, Mg₃(PO₄)₂, satisfies the charges of both the magnesium (Mg²⁺) and the phosphate ions (PO₄²⁻). Mg²⁺ has three ions, which means the positive charge will be 6 +. The phosphate ions has a negative charge of 3, so two ions of phosphate can counter the six positive charges in the compound. So, the statement is true
B. The compound is not covalent, as Mg²⁺ and PO₄²⁻ ions are bounded by electrostatic forces. So, the statement is false
C. The stable charge of Mg is 2+. Mg is a s block element in the third period. It does not have any empty inner d orbital. Which makes 2+ oxidation state the most stable. So, the statement is true
D. The phosphate group is composed of phosphorous atom covalently bonded to four oxygen atoms. Hence, the compound DOES NOT contain ONLY ionic bonds. So, the given statement is false
The compound forms between magnesium cation and phosphate anion have the chemical formula of the compound is Mg3(PO4)2 and the most stable form of a magnesium ion has a charge of 2+.
The correct options are (A) The chemical formula of the compound is Mg3(PO4)2, (C) The most stable form of a magnesium ion has a charge of 2+.
Magnesium phosphate Magnesium phosphate is a common term for magnesium and phosphate salts that come in a variety of forms and hydrates.It is found in four forms.Thus, the correct options to follow the statements are (A) and (C).
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What new idea about light did Einstein use to explain the photoelectric effect? Why does the photoelectric effect exhibit a threshold frequency? Why does it not exhibit a time lag?
Answer and Explanation:
- Einstein used the new idea that light consists of small packages of energy, which he later called photons. That light is particulate and is quantized in photons.
- The photoelectric effect basically explains that electrons on a metallic surface can gain enough energy from light (photons) incidented on such surfaces and break free of the surface.
Since a beam of light consists of an enormous number of photons,intensity of
light (brightness) is related to the number of photons,but not to the energy of each. Therefore, a photon of a certain minimum energy must be absorbed in order free an electron from the surface. Energy is proportional to frequency (E = hf) so, the theory predicts a threshold freguency that corresponds to the minimum energy (work function of the metal) required to liberate the electrons.
- There is no time lag because electrons break free, the moment they absorb photons of enough energy. A current will flow as soon as a photon of sufficient energy reaches the metal plate and that is why there is no lag time.
Arrange each set in order of increasing atomic size:
(a) Rb, K, Cs (b) C, O, Be (c) Cl, K, S (d) Mg, K, Ca
Answer:
Part A:
Order: K<Rb<Cs
Part B:
Order: O<C<Be
Part C:
Order:CL<S<K
Part D:
Order:Mg<Ca<K
Explanation:
Atomic Size:
It is the distance from the center to atom to the valance shell electron. It is very difficult to measure the atomic size because there is definite boundary of atom.
Trend:
Moving from top to bottom in a group, Atomic Size increases.
Moving from left to right in a period, Atomic size generally decreases.
On the basis of above trend we will solve our question:
Part A:
All elements belong to Group 1:
Moving from top to bottom in a group, Atomic Size increases.
Order: K<Rb<Cs
Part B:
All elements belong to 2nd Period:
Moving from left to right in a period, Atomic size generally decreases.
Order: O<C<Be
Part C:
S belongs to 3rd Period, K, Cl belong to 4th period
Order:CL<S<K
Part D:
Mg is above Ca in group 2 and K is before Ca in 4th period
From trends described above:
Order:Mg<Ca<K
Final answer:
Each set is arranged in order of increasing atomic size, reflecting the trend that atomic size increases down a group and decreases across a period.
Explanation:
Arranging each set in order of increasing atomic size based on their positions in the periodic table:
(a) K, Rb, Cs
(b) Be, C, O
(c) Cl, S, K
(d) Mg, Ca, K
Atomic size typically increases from top to bottom within a group and decreases from left to right across a period. So in each set, the element located further down a group will be larger, and the element on the farther left of a period will be smaller.
Which of these electron transitions correspond to absorption of energy and which to emission?
(a) n = 2 to n = 4
(b) n = 3 to n = 1
(c) n = 5 to n = 2
(d) n = 3 to n = 4
Answer:
For a: The energy will be absorbed.
For b: The energy will be released.
For c: The energy will be released.
For d: The energy will be absorbed.
Explanation:
There are two ways in which electrons can transition between energy levels:
Absorption spectra: This type of spectra is seen when an electron jumps from lower energy level to higher energy level. In this process, energy is absorbed.Emission spectra: This type of spectra is seen when an electron jumps from higher energy level to lower energy level. In this process, energy is released in the form of photons.Equation used to calculate the energy for a transition:
[tex]E=-2.178\times 10^{-18}J\left(\frac{1}{n_i^2}-\frac{1}{n_f^2} \right )[/tex]
For the given options:
For a: n = 2 to n = 4As, the electron is getting jumped from lower energy level (n = 2) to higher energy level (n = 4), the energy will be absorbed.
For b: n = 3 to n = 1As, the electron is getting jumped from higher energy level (n = 3) to lower energy level (n = 1), the energy will be released.
For c: n = 5 to n = 2As, the electron is getting jumped from higher energy level (n = 5) to lower energy level (n = 2), the energy will be released.
For d: n = 3 to n = 4As, the electron is getting jumped from lower energy level (n = 3) to higher energy level (n = 4), the energy will be absorbed.
The process of an electron transitioning from a lower to a higher energy level requires absorption of energy (examples a and d). Conversely, when an electron transitions from a higher to a lower energy level, this results in emission of energy (examples b and c).
Explanation:In an atom, different energy levels are denoted by the principal quantum number 'n'. Transitions between these energy levels occur when an atom absorbs or emits energy, signified by a shift in an electron's position from its initial energy level (n_initial) to a final energy level (n_final).
(a) n = 2 to n = 4 is an absorption of energy. The electron rises from a lower energy level (n=2) to a higher energy level (n=4). (b) n = 3 to n = 1 is an emission of energy. The electron falls from a higher energy level (n=3) to a lower energy level (n=1). (c) n = 5 to n = 2 is also an emission of energy, the electron falls from a higher energy level (n=5) to a lower energy level (n=2).(d) n = 3 to n = 4 is another example of absorption of energy. The electron rises from a lower energy level (n=3) to a higher energy level (n=4).Learn more about Energy Transitions here:
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There are 3 different possible structures (known as isomers) for a dibromoethene molecule, C2H2Br2. One of them has no net dipole moment, but the other two do. Draw a structure for each isomer. Include H atoms.
Explanation:
Compounds having same molecular formula but different structural and spatial arrangement are isomers.
Three isomers are possible for dibromomethene.
In one structure (IUPAC name: 1,1-dibromomethene), both the bromine atoms are attached to one carbon atom.
In another two structures (Cis and trans), two bromine atoms are attached to two different carbon atoms.
In Cis 1,2-dibromomethene, two bromine atoms are present on the same side.
Whereas in Cis 1,2-dibromomethene, two bromine atoms are present on the opposite side and hence, does not have net dipole moment.
Biochemists consider the citric acid cycle to be the central reaction sequence in metabolism. One of the key steps is an oxidation catalyzed by the enzyme isocitrate dehydrogenase and the oxidizing agent NAD+. Under certain conditions, the reaction in yeast obeys llth-order kinetics:
Rate = k[enzyme][isocitrate]4[AMP]2[NAD+]m[Mg2+]2,
What is the order with respect to NAD+?
Answer:
Order w.r.t. [tex]NAD^+[/tex] = 2
Explanation:
According to the law of mass action:-
The rate of the reaction is directly proportional to the active concentration of the reactant which each are raised to the experimentally determined coefficients which are known as orders. The rate is determined by the slowest step in the reaction mechanics.
Order of in the mass action law is the coefficient which is raised to the active concentration of the reactants. It is experimentally determined and can be zero, positive negative or fractional.
The order of the whole reaction is the sum of the order of each reactant which is raised to its power in the rate law.
The given rate law is:-
[tex]Rate = k[enzyme][isocitrate]^4[AMP]^2[NAD^+]^m[Mg^{2+}]^2[/tex]
The overall rate = 11
Rate of overall reaction = 1 + 4 + 2 + m + 2 = 11
9 + m = 11
m = 2
Order w.r.t. [tex]NAD^+[/tex] = 2
What intermolecular forces exist between molecules of ethanol? Choose one or more: A. Dispersion B. Dipole-dipole C. Dipole-induced dipole D. Hydrogen bonding
Answer: Option (D) is the correct answer.
Explanation:
Dipole-dipole interactions are defined as the interactions that occur when partial positive charge on an atom is attracted by partial negative charge on another atom.
When a polar molecule produces a dipole on a non-polar molecule through distribution of electrons then it is known as dipole-induced forces.
Hydrogen bonding is defined as a bonding which exists between a hydrogen atom and an electronegative atom like O, N and F.
As the chemical formula of ethanol is [tex]CH_{3}CH_{2}OH[/tex]. So, hydrogen bonding will exist in a molecule of ethanol ([tex]CH_{3}CH_{2}OH[/tex]). Since, hydrogen atom is attached with electronegative oxygen atom so, hydrogen bonding will exist.
Thus, we can conclude that hydrogen bonding is the intermolecular forces exist between molecules of ethanol.
Ethanol contains Dispersion, Dipole-dipole, and Hydrogen bonding intermolecular forces. Dispersion forces come from fluctuations in electron distribution. Dipole-dipole forces are due to ethanol's polar nature, and Hydrogen bonding is between the hydrogen and oxygen in the -OH group.
Explanation:The intermolecular forces that exist between molecules of ethanol include Dispersion, Dipole-dipole, and Hydrogen bonding. Dispersion forces, or London dispersion forces, originate from temporary fluctuations in the electron distribution within the molecules. Dipole-dipole forces are due to the polar nature of the ethanol molecule, which has a hydroxyl (-OH) group that gives rise to a dipole. Lastly, Hydrogen bonding is the strongest intermolecular force in this case and occurs between the hydrogen atom in the -OH group of one ethanol molecule and the oxygen atom in the -OH group of another ethanol molecule.
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Water (3110 g ) is heated until it just begins to boil. If the water absorbs 5.19×105 J of heat in the process, what was the initial temperature of the water that this will require a total of 3600 kcal of energy for the trip. For her food supply, she decides to take nutrition bars. The label states that each bar contains 50 g of carbohydrates, 10 g of fat, and 40 g of protein.
Answer:
The question requires the value of the initial temperature which is found to be 60.266 °C ≅ 60.3 °C
Explanation:
To solve this question we list out the given variables as follows
Mass of water = 3110 g
Heat energy absorbed = 5.19 × 10⁵ J
Heat Energy required to raise the temperature of water to boiling point =
ΔH = m×C×Δθ where
m = mass of waster = 3110 g = 3.11 kg
C = specific heat capacity of water = 4.2 J/g°C
Δθ = Temperature change = T₂ - T₁ and
T₂ = 100°C which is the normal boiling point temperature of water
Hence 5.19 ×10⁵ J = 3110 g × 4.2 J/g°C ×Δθ
from where Δθ = (5.19 ×10⁵ J)/(13062 J/°C) = 39.73 °C
But Δθ = T₂ - T₁ = 100 °C- T₁ = 39.73 °C then
T₁ = -100 °C - 39.73 °C = 60.266 °C
Hence the initial temperature of the water is 60.266 °C
Final answer:
The initial temperature of the water can be calculated using the specific heat of water (4.184 J/g °C) and the amount of heat absorbed (5.19×10^5 J) before boiling.
Explanation:
The specific heat of water is a critical concept in thermodynamics and is essential for solving problems involving temperature changes. To calculate the initial temperature of the water, we utilize the specific heat capacity, which for water is 4.184 J/g °C. The amount of heat required to raise the temperature of a given mass of water is determined by this specific heat capacity.
For instance, using the information provided, if water absorbs 5.19×105 J of heat, we can set up an equation to find the initial temperature (Tinitial) before it began to boil. Using the formula q = mcΔT, where 'q' is the heat absorbed, 'm' is the mass, 'c' is the specific heat capacity, and 'ΔT' is the change in temperature, we find:
5.19×105 J = (3110 g)(4.184 J/g°C)(100°C - Tinitial)
This equation can be solved for Tinitial to find the initial temperature of the water.
Consider the following reaction: 2{\rm{ N}}_2 {\rm{O(}}g)\; \rightarrow \;2{\rm{ N}}_2 (g)\; + \;{\rm{O}}_2 (g)
a. In the first 12.0 s of the reaction, 1.7×10−2 mol of {\rm{O}}_2 is produced in a reaction vessel with a volume of 0.240 L. What is the average rate of the reaction over this time interval?
b. Predict the rate of change in the concentration of {\rm{N}}_2 {\rm{O}} over this time interval. In other words, what is {\Delta [{\rm{N}}_2 {\rm{O}}]}/{\Delta t}?
Answer:
a. 5.9 × 10⁻³ M/s
b. 0.012 M/s
Explanation:
Let's consider the following reaction.
2 N₂O(g) → 2 N₂(g) + O₂(g)
a.
Time (t): 12.0 s
Δn(O₂): 1.7 × 10⁻² mol
Volume (V): 0.240 L
We can find the average rate of the reaction over this time interval using the following expression.
r = Δn(O₂) / V × t
r = 1.7 × 10⁻² mol / 0.240 L × 12.0 s
r = 5.9 × 10⁻³ M/s
b. The molar ratio of N₂O to O₂ is 2:1. The rate of change of N₂O is:
5.9 × 10⁻³ mol O₂/L.s × (2 mol N₂O/1 mol O₂) = 0.012 M/s
During the rGFP purification experiment, the instructor will have to make breaking buffer for the students to use. This buffer contains 150mM NaCl. Given a bottle of crystalline NaCl (M.W. = 40g/mole), describe how you would make 500ml of 150mM NaCl
Explanation:
1mM of solution means millimolar, that is 1 millimole of solute is contained in 1 liter of solvent.
Converting mM to M,
150mM to M = 150*1 x 10^-3
= 0.15M
Number of moles = molar concentration * volume
= 0.15*0.5
= 0.075 moles.
Molar mass of NaCl = 23 + 35.5
= 58.5 g/mol
Mass of NaCl = molar mass * number of moles
= 58.5*0.075
= 4.3875g
Description:
• 4.3875 g of NaCl is measured on a measuring scale and poured in a conical flask.
• 1 liter of solvent is measured with a measuring cylinder and poured into the conical flask and mixed.
How do transmittance, absorbance, and molar absorptivity differ? Which one is proportional to concentration?
Answer:
The transmittance is the amount of energy that a body goes through in a certain amount of time without being absorbed and the absorbance is the amount of light that is absorbed by a solution.
There is no difference between absorptivity and molar absorptivity because the two terms express the same idea, because molar absorptivity is the absorbance of a solution per unit path length and concentration, so that the absorbance is proportional to concentration.
Final answer:
Transmittance is the percentage of light that passes through a sample, absorbance is the logarithmic measure of light absorption, and molar absorptivity is an intrinsic constant correlating absorbance to concentration. Absorbance is directly proportional to concentration, which makes it the preferred measure for determining a substance's concentration in a solution.
Explanation:
The terms transmittance, absorbance, and molar absorptivity are key concepts in spectrophotometry, each describing different aspects of how light interacts with a sample.
Transmittance is a measure of the amount of light that passes through a sample and is typically expressed as a percentage. In contrast, absorbance measures the amount of light absorbed by a sample and is a logarithmic function of transmittance. The formula given A = εbC explains the direct proportionality of absorbance (A) to the concentration (C) of the absorbing species, path length (b), and the molar absorptivity (ε). Molar absorptivity, also called the extinction coefficient, is a constant that illustrates how strongly a substance absorbs light at a given wavelength and is intrinsic to each specific substance.
When determining the concentration of a solution, absorbance is preferred as it is a linear function of concentration. In practical applications, a spectroscopic method is selected to target a specific wavelength that is well-absorbed by the substance of interest, making use of the molar absorptivity to determine concentrations accurately.