Answer:(1) 6 sodium ions
(2)The movement of iodide ions occurs in the same direction as the sodium ions.
Explanation: Sodium-iodide symporter actively transports 2 sodium ions together with one iodide ions across the basement membrane into the thyroid follicular cells.(therefore for production of a single molecule of T3 3×2=6 sodium ions)This system utilises the concentration of sodium ions so that iodide ions can move against its concentration gradient.
Describe the pattern of temperature changes within the layers of the atmosphere. Why do you think temperature changes follow this unique pattern
Answer:
The atmosphere refers to the gaseous envelope of earth, comprised of variable gases with definite proportions. The layers of the earth's atmosphere are as follows-
Troposphere- This layer starts from the ground and extends up to a height of about 10 km. Here, the temperature decreases with the increasing altitude. All the weather phenomenon takes place in this layer. Stratosphere- It starts from 10 km and extends up to a height of about 50 km. Here the temperature increases as the altitude increase. This is because of the presence of the ozone layer that receives the harmful UV radiation emitted from the sun. Mesosphere- This layer extends from a height of about 50 km to about 80 km above the earth's surface. Here, again the temperature decreases with the increasing altitude. Thermosphere- This layer starts from a height of about 80 km and extends up to about 500 km above the ground surface. In this region again the temperature increases with the increasing elevation. Exosphere- This layer ranges from about 500 km to 10,000 km above the earth's surface. Here, the temperature gradually increases with the increasing height.This variation in temperature occurs because of the certain reason. In the troposphere and the mesosphere, the temperature decreases with height because the pressure and height are inversely proportional to each other. The stratosphere experiences increasing temperature because of the presence of the ozone layer that is responsible for holding the greenhouse gases and the harmful UV radiation. The thermosphere and the exosphere experience high temperatures because of the receiving of the direct sunlight. Due to these above reason, there occurs this temperature change in a unique pattern.
The temperature changes within the layers of the atmosphere follow a pattern of alternating increases and decreases. This unique pattern is influenced by factors such as sun angle, insolation intensity, day length, and proximity to water bodies.
Explanation:The pattern of temperature changes within the layers of the atmosphere is characterized by alternating increases and decreases in temperature. This pattern can be observed in the five layers of the atmosphere, namely the troposphere, stratosphere, mesosphere, thermosphere, and exosphere. The temperature gradient varies with each layer, with the troposphere being the coldest and the thermosphere being the hottest. The unique pattern of temperature changes is caused by various factors such as sun angle, insolation intensity, day length, and proximity to water bodies.
A gas in a balloon at constant pressure has a volume of 185 mL at -125*C. What is its volume at 31.0*C? Show all work including what equation or gas law you use.
Answer:
380 mL is the new volume
Explanation:
At constant pressure.
V₁ / T₁ = V₂ / T₂
Temperature must be in Absolute Values (T°K = T°C + 273)
-125°C + 273 = 148 K
31°C + 273 = 304 K
185 mL / 148 K = V₂ / 304 K
V₂ = (185 mL / 148 K) . 304 K → 380 mL
Patrice walks 4.0 blocks east and then turns north and jogs 6.0 blocks. She then turns west and walks another 4.0 blocks. What is the distance she has traveled?
0.0 blocks
8.0 blocks
6.0 blocks
14.0 blocks
Answer:
14.0 blocks
Explanation:
Distance travelled
= 4.0 blocks + 6.0 blocks + 4.0 blocks
= 14.0 blocks
Patrice has travelled 14.0 blocks.
Find the value of each of these quantities. a) C(5,1) c) C(8, 4) e) C(8, 0) b) C(5,3) d) C(8, 8) f ) C(12, 6)
The values of the given combinations are: a) 5, b) 10, c) 70, d) 1, e) 1, f) 924.
Explanation:a) C(5,1) = 5b) C(5,3) = 10c) C(8,4) = 70d) C(8,8) = 1e) C(8,0) = 1f) C(12,6) = 924Learn more about Combinations here:https://brainly.com/question/37999460
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The values of the given combinations are: a) 5, b) 10, c) 70, d) 1, e) 1, f) 924.
Explanation:a) C(5,1) = 5b) C(5,3) = 10c) C(8,4) = 70d) C(8,8) = 1e) C(8,0) = 1f) C(12,6) = 924Learn more about Combinations here:https://brainly.com/question/30646507
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Two samples of carbon tetrachloride were decomposed into their constituent elements. One sample produced 38.9 g of carbon and 451 g of chlorine, and the other sample produced 14.8 g of carbon and 135 g of chlorine. Are these results consistent with the law of definite proportions? Show why or why not.
Answer:
No.
Explanation:
The results mentioned are not consistent with the law of definite proportions.
Law of definite proportions states that a chemical compound contains exactly the same elements in the same proportion by weight independent of its source and method of it's preparation.
In the given question, the first sample contains 38.9 g of carbon and 451 g of chlorine that means the sample has 8% of carbon and 92% of chlorine.
On the other hand, second sample contains 14.8 g of carbon and 135 g of chlorine which means that this sample has 10% of carbon and 90% of chlorine.
Since the constituent elements in both the samples are not in fixed and constant proportions (by mass), the law of definite proportions fails here.
An unknown element is found to contain isotopes with the following masses and natural abundances: 38.9637 amu (93.08%), 39.9640 amu (0.012%), and 40.9618 amu (6.91%). Using these data, identify the element. a. S b. K c. Cld. Ca e. Ar
Answer: The unknown element is potassium.
Explanation:
Average atomic mass of an element is defined as the sum of masses of each isotope each multiplied by their natural fractional abundance.
Formula used to calculate average atomic mass follows:
[tex]\text{Average atomic mass }=\sum_{i=1}^n\text{(Atomic mass of an isotopes)}_i\times \text{(Fractional abundance})_i[/tex] .....(1)
For isotope 1:Mass of isotope 1 = 38.9637 amu
Percentage abundance of isotope 1 = 93.08 %
Fractional abundance of isotope 1 = 0.9308
For isotope 2:Mass of isotope 2 = 39.9640 amu
Percentage abundance of isotope 2 = 0.012 %
Fractional abundance of isotope 2 = 0.00012
For isotope 3:Mass of isotope 3 = 40.9618 amu
Percentage abundance of isotope 3 = 6.91 %
Fractional abundance of isotope 3 = 0.0691
Putting values in equation 1, we get:
[tex]\text{Average atomic mass of Z}=[(38.9637\times 0.9308)+(39.9640\times 0.00012)+(40.9618\times 0.0691)][/tex]
[tex]\text{Average atomic mass of Z}=38.85amu[/tex]
For the given options:
Option a: Average atomic mass of Sulfur = 32.065 amu
Option b: Average atomic mass of Potassium = 39.09 amu
Option c: Average atomic mass of Chlorine = 35.45 amu
Option d: Average atomic mass of Calcium = 40.078 amu
Option e: Average atomic mass of Argon = 39.94 amu
As, the average atomic mass of unknown element is near to the average atomic mass of potassium. So, the unknown element is potassium.
Hence, the unknown element is potassium.
The element with isotopes of masses 38.9637 amu, 39.9640 amu, and 40.9618 amu, and natural abundances of 93.08%, 0.012%, and 6.91% respectively, is Calcium (Ca).
Explanation:To identify the element based on its isotopes, we need to calculate the average atomic mass of the element. This can be done by multiplying the mass of each isotope by its natural abundance (expressed as a decimal), and then summing up these products. In this case, the element with isotopes of masses 38.9637 amu, 39.9640 amu, and 40.9618 amu, and natural abundances of 93.08%, 0.012%, and 6.91% respectively, is Calcium (Ca). The average atomic mass of calcium can be calculated as follows:
(38.9637 amu * 0.9308) + (39.9640 amu * 0.00012) + (40.9618 amu * 0.0691) = 40.08 amu
Therefore, the element is calcium (Ca).
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An unknown compound contains only carbon, hydrogen, and oxygen (CxHyOzCxHyOz). Combustion of 5.50 gg of this compound produced 8.07 gg of carbon dioxide and 3.30 gg of water. How many moles of carbon, C, were in the original sample? Express your answer to three significant figures and include the appropriate units.
Answer:
Moles of Carbon in the product = 0.183 mol
Explanation:
Complete combustion of an organic compound in the presence of excess oxygen will give carbon dioxide (CO2) and water vapour(H2O).
Equation of reaction
CxHyOz(s) + (2x + y/2 - z)/2 O2(g) --> x CO2(g) + y/2 H2O(l)
Moles of products
CO2
Molar mass of CO2 = 12 + (16*2)
= 44 g/mol
n(CO2) = 8.07/44.0
= 0.183 mol
One compound of CO2 has 1 Carbon atom and 2 Oxygen atom.
So if we have,
0.183 moles of carbon dioxide then
0.183 moles of carbon.
The mass of carbon in the product, m = 0.183*12
= 2.20 g
H2O:
Molar mass of H2O = (1*2) + 16
= 18 g/mol
Number of moles of H2O =
= 3.3/18
= 0.183 mol
One compound of H2O has 2 Hydrogen atom and 1 Oxygen atom.
0.183 moles of water then we also have
= 2*(0.183)
= 0.367 moles of hydrogen in the sample.
The mass of hydrogen in the compound, m
= 0.367*1
= 0.367 g
Adding these two values together will give us the mass of our compound that C and H;
2.2 + 0.367
= 2.567 g
So for the Oxygen,
5.5 g - 2.567
= 2.933 g
Moles of Oxygen;
Molar mass of O = 16 g/mol
= 2.933/16
= 0.183 mol
There are 0.030 moles of carbon in the original sample as per the mole concept.
Mole is defined as the unit of amount of substance . It is the quantity measure of amount of substance of how many elementary particles are present in a given substance.
It is defined as exactly 6.022×10²³ elementary entities. The elementary entity can be a molecule, atom ion depending on the type of substance. Amount of elementary entities in a mole is called as Avogadro's number.
It is given by the formula,
[tex]\rm{number \ of \ moles}=\dfrac{\rm{mass}}{molar \ mass}[/tex]
The given values are,mass=[tex]5.50 \ g[/tex]
molar mass=[tex]178g/mol[/tex]
Substitution of values in formula gives,
[tex]\rm{number \ of \ moles}=\dfrac{5.50}{178}\\=0.030[/tex]
Thus, there are 0.030 moles of carbon in the original sample as per the mole concept.
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What is the mass percent of NaCl in a solution made by dissolving 23.0 g of NaCl in 150.0 g of water?
Answer:
13.3 % by mass of NaCl
Explanation:
Solution is made of NaCl and water
Mass of NaCl = 23 g → Solute
Mass of H₂O = 150 g → Solvent
Total mass of solution = Solute + Solvent
23 + 150 = 173 g
Mass percent of NaCl → (Mass of solute / Mass of solution) . 100
(23g / 173g) . 100 = 13.3 g
The mass percent of NaCl in a solution made by dissolving 23.0 g of NaCl in 150.0 g of water is approximately 13.3%.
The mass percent of NaCl in a solution is found by dividing the mass of the solute (NaCl) by the total mass of the solution (solute plus solvent), and then multiplying by 100%.
For a solution made by dissolving 23.0 g of NaCl in 150.0 g of water, the total mass of the solution would be the mass of NaCl plus the mass of water, which is 23.0 g + 150.0 g = 173.0 g. The mass percent of NaCl is then calculated as:
Calculate the total mass of the solution: 23.0 g NaCl + 150.0 g water = 173.0 gDivide the mass of NaCl by the total mass of the solution: 23.0 g NaCl ÷ 173.0 g solutionMultiply by 100% to get the mass percent: (23.0 g ÷ 173.0 g) × 100% = 13.3%So, the mass percent of NaCl in the solution is 13.3%.
The gears on a bicycle are an example of what type of simple machine?
Lever
Wheel and Axle
Inclined plane
Pulley
The gears on a bicycle are an example of the wheel and axle type of simple machine, which includes a rod (axle) attached to the center of a wheel to amplify force or speed, and combines with levers and pulleys in the full mechanism of the bicycle.
The gears on a bicycle are an example of the wheel and axle type of simple machine. This particular type of simple machine consists of a rod (the axle) fixed to the center of a wheel, which together can amplify force or speed. Though similar to a lever, the wheel and axle design allows for continuous rotational motion, which is ideal for bicycles. According to renaissance scientists, there are six classifications of simple machines, which are the lever, wheel and axle, pulley, inclined plane, wedge, and screw. Bicycles actually combine several types of simple machines, including wheel and axles, levers, and in some cases, pulleys.
Ethanol contains the elements carbon, hydrogen, and oxygen. When ethanol burns, it chemically reacts with oxygen gas. C2H6O + O2 ethanol oxygen gas What elements will be present in the substances that are created when ethanol burns?
Answer:
The elements that will be present after the burning of Ethanol are;
(i) Carbon
(ii) Oxygen
(iii) Hydrogen
Explanation:
The balanced chemical equation for the burning of ethanol is as follow;
C₂H₅OH + 3 O₂ → 2 CO₂ + 3 H₂O
It can be observed in given balanced chemical equation that there three elements involved in this entire reaction. The elements that present in the reactant side are also found on the product side. It means that the elements have just rearranged going from reactant to product.
This means that this reaction is obeying Law of Conservation of Mass which states that mass can neither be created nor destroyed but it can be changed from one form to another hence, to keep the mass on both sides of the reaction balanced the same elements should be present on the product side too.
Answer: carbon, hydrogen, and oxygen only
Explanation: When a chemical reaction occurs, the atoms in the original set of substances are rearranged to form a new set of substances. The number of atoms of each element does not change.
The elements carbon, hydrogen, and oxygen are the only elements present in the original substances, so the only elements in the final substances after the reaction will be carbon, hydrogen, and oxygen, as well. The number of atoms of each element must be the same before and after the reaction.
Calcium carbonate is most likely to dissolve in water with which characteristics?
a. Low pressure and colder temperatures
b. Low carbon dioxide and warmer temperatures
c. Lots of carbon dioxide and warmer temperatures
d. Low pressure and warmer temperatures
e. Lots of carbon dioxide and colder temperatures
Calcium carbonate is most likely to dissolve in water with:
e. Lots of Carbon dioxide and colder temperature.
Explanation:
Calcium carbonate is very sparingly soluble in water. However, it has been observed to dissolve in cold water with higher concentration of Carbon dioxide.The reason behind the observation is the formation of Calcium bicarbonate which is soluble in water.Higher concentration of Carbon dioxide in water turns it acidic. When this acidic water reacts with calcium carbonate it forms Calcium bicarbonate which is soluble in water.So,Calcium carbonate is most likely to dissolve in water with lots of Carbon dioxide and colder temperature.Calcium carbonate is most likely to dissolve in water that has a lot of carbon dioxide and is colder, as CO2 creates acidic conditions which increase CaCO3 solubility.
Explanation:Calcium carbonate (CaCO3) is known to be more soluble in water when the conditions are acidic. The presence of carbon dioxide (CO2) in the water greatly inclines the water to be more acidic as CO2 reacts with H2O to form carbonic acid (H2CO3), which further dissociates into hydrogen ions (H+) and bicarbonate ions (HCO3-). This series of reactions results in a decrease in the concentration of carbonate ions, enabling more CaCO3 to dissolve.
Therefore, in accordance with the provided information, calcium carbonate is most likely to dissolve in water with characteristics described in option (e), which is 'lots of carbon dioxide and colder temperatures.' Colder temperatures are more favorable compared to warmer temperatures for the solubility of gas-like CO2, thereby increasing the acidity and aiding in the dissolution of CaCO3.
The reaction (CH3)3CBr + OH- (CH3)3COH + Br- in a certain solvent is first order with respect to (CH3)3CBr and zero order with respect to OH-. In several experiment, the rate constant k was determined at different temperatures. A plot of ln(k) versus 1/T was constructed resulting in a straight line with a slope value of –1.10 x 104 K and a y-intercept of 33.5.
Answer and Explanation:
The rate constant (K) is related to activation energy (Ea), frequency factor (A) and temperature (T) in Kelvin by the equation
R = molar gas constant
K = A(e^(-Ea/RT))
Taking natural log of both sides
In K = In A - (Ea/RT)
In K = (-Ea/R)(1/T) + In A
Comparing this to the equation of a straight line; y = mx + c
y = In K, slope, m = (-Ea/R), x = (1/T) and intercept, c = In A
a) From the question, m = (-Ea/R) = -1.10 × (10^4) K
(-Ea/R) = -1.10 × (10^4) = -11000
R = 8.314 J/K.mol
Ea = -11000 × 8.314 = 91454 J/mol = 91.454 KJ/mol
b) c = In A = 33.5
A = e^33.5 = (3.54 × (10^14))/s
c) K = A(e^(-Ea/RT))
A = (3.54 × (10^14))/s, Ea = 91454 J/mol, T = 25°C = 298.15 K, R = 8.314 J/K.mol
K = (3.54 × (10^14))(e^(-91454/(8.314×298.15))) = 0.0336/s
QED!
This question pertains to the rate of a chemical reaction, which is first order with respect to (CH3)3CBr and zero order with respect to OH-. An Arrhenius plot indicating temperature and rate constant is used to find activation energy and frequency factor.
Explanation:The reaction you're describing is a typical chemical reaction. This type of reaction is first order with respect to (CH3)3CBr, which means the rate of the reaction depends on the concentration of this compound. OH-, on the other hand, is zero order, meaning its concentration doesn't affect the reaction's rate.
The plot you've mentioned is an Arrhenius plot, and it is used to determine the activation energy and frequency factor of a reaction from the slop and y-intercept respectively. Given the slope value of –1.10 x 10^4 K you mentioned, you can find the activation energy (Ea) from the formula Ea = -slope * R , where the slope is –1.10 x 10^4 K and R is the universal gas constant (8.3145 Joule/(mole*K)). Similarly, from the y-intercept value, you can find the frequency factor by the formula A=e^(y-intercept), where A is frequency factor and e is natural base.
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Arrange the listed ions in increasing order of strength of reducing agent.
Aluminum:
Cobalt:
Copper:
Chromium:
Mercury:
Silver
Answer:
Arrange the listed ions in increasing order of strength of reducing agent.
Aluminum: 6
Cobalt: 4
Copper: 3
Chromium: 5
Mercury: 1
Silver: 2
Answer: 6, 4, 3 , 5 , 1 , 2
Aluminum: 6
Cobalt: 4
Copper: 3
Chromium: 5
Mercury: 1
Silver: 2
Explanation:
Over time, Hinduism has become/is becoming Select one: a. less homogeneous. b. more localized. c. more homogeneous. d. more racialized.
Answer:
d. Localized.
Explanation:
You posted this question in the chemistry section. The whole exercise requires you to understand the terms in a chemical context. So let's look at the three terms: homogeneous, localized, and radicalized.
Homogeneous
A chemical substance is said to be homogeneous if the chemical composition is the same throughout. It means the substance must have the same states. For example, a mixture of undiluted orange juice forms a homogeneous solution once it is diluted in water. It means that there is perfect mixing to have a uniform liquid state.
Localized
The terminology is often applied to atoms or chemical structures, particularly metals and acids. For example, atoms have localized electrons in the orbitals. It means that the electron orbits in the region for 95 % of its time. Localized means belonging to one region. This applies to the religion.
Radical
The term applies to highly reactive atomic species, normally called ions. These elements seek electrons and are highly "reactive." The ions are called radicals in this sense.
Liquid 1 reacts with Liquid 2, producing a solid and a gas. Using this scenario, which supports the law of conse
mass?
mass of Liquid 1 + mass of solid = mass of Liquid 2 + mass of gas
mass of Liquid 1 - mass of solid = mass of Liquid 2-mass of gas
mass of Liquid 1 - mass of Liquid 2 = mass of solid + mass of gas
mass of Liquid 1 + mass of Liquid 2 = mass of solid + mass of gas
Answer:
The answer to your question is the fourth one.
Explanation:
From the description, we know that the reactants are two liquids and the products are a solid and a gas.
The first option is incorrect because it mentions that the reactants are one liquid and solid.
The second option is also incorrect for the same reason as the first one and one of the products must be a solid.
The third option is incorrect besides there are two liquids in the reactants and a solid and gas in the liquids there is a minus sign that is not possible.
The fourth option is the correct one.
A chemist began with 61.5 grams of naclo3.After collecting and drying the product, 30 grams of nacl was obtained. what was the theoretical yield of nacl
Answer:
33.78 g
Explanation:
NaClO3 decomposes to NaCl and O2 by this reaction:
2NaClO3 --> 2NaCl + 3O2
Let's determines the mole of chlorate we used (mass / molar mass)
61.5 g / 106.45 g/mol = 0.578 moles.
Ratio is 2:2, so x amount of chlorate will produce x amount of chloride. In conclussion we made 0.578 moles of NaCl from 0.578 moles of chlorate. Let's convert the moles to mass:
0.578 mol . 58.45g/1mol = 33.78 g
That is the theoretical yield of NaCl.
If you analyzed each of the substances NaBr, KOH, CrPO4, Pb(OH)2, RbCl, LiNO3 by mixing them with water in a beaker, which substances would be most likely to fall to the bottom of the beaker?
Explanation:
Substances would be most likely to fall to the bottom of the beaker are CrPO4, Pb(OH)2.
All nitrates are soluble in water therefore, LiNO3 will be soluble. Also, sodium potassium salts are always soluble therefore, NaBr, KOH are soluble. Moreover. RbCl are generally soluble therefore, leaving the other two.
How many moles of hydrogen gas are present in a 50 liter steel cylinder if the pressure is 10 atm and the temperature is 27 degrees Celsius?
Answer:
12.2 moles of H₂
Explanation:
P . V = n . R . T is the Ideal Gases Law, which is useful to solve this:
First of all, we need to convert the T°C to T° K
T° K = T°C + 273 → 27°C + 273 = 300 K
Let's replace the data given: 10 atm . 50L = m . 0.082L.atm/m.K . 300K
500 L.atm / 0.082L.atm/m.K . 300K = m
12.2 moles = n
What is the percentage yield of O2 if 12.3 g of KClO3 (molar mass 123 g) is decomposed to produce 3.2 g of O2 (molar mass 32 g) according to the equation above?
Answer:
The percentage yield of O2 is 66.7%
Explanation:
Reaction for decomposition of potassium chlorate is:
2KClO₃ → 2KCl + 3O₂
The products are potassium chloride and oxygen.
Let's find out the moles of chlorate.
Mass / Molar mass = Moles
12.3 g / 123 g/mol = 0.1 mol
So ratio is 2:3, 2 moles of chlorate produce 3 mol of oxygen.
Then, 0.1 mol of chlorate may produce (0.1 .3)/ 2 = 0.15 moles
Let's convert the moles of produced oxygen, as to find out the theoretical yield.
0.15 mol . 32 g/ 1mol = 4.8 g
To calculate the percentage yield, the formula is
(Produced Yield / Theoretical yield) . 100 =
(3.2g / 4.8g) . 100 = 66.7 %
The branch of science which deals with the study of chemicals and their bond is called chemistry.
The correct percentage yield of O2 is 66.7%
The Reaction for decomposition of potassium chlorate is as follows:-
[tex]2KClO_3 <---> 2KCl + 3O_2[/tex]
The formula is as follows:- [tex]\frac{Mass }{Molar\ mass} = Moles[/tex]
After putting the value in the question is:-
[tex]\frac{12.3 g}{123} = 0.1 mol[/tex]
So the ratio present in the reaction is 2:3.
Therefore, the 0.1 mole of chlorate produce [tex]\frac{(0.1 *3)}{2} = 0.15 moles[/tex]
Convert them into molar mass is:-
[tex]\frac{0.15*32 g}{1mol} = 4.8 g[/tex]
The percentage of the compound is [tex]\frac{(3.2g}{4.8g}* 100 = 66.7 %[/tex].
Hence, the correct answer is 66.7%
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A minerals luster is produced by its ability to transmit light. Opaque minerals always have a metallic luster because they do not transmit any light. True False
Explanation:
The above statement is incorrect. The luster in minerals is not because of the their ability to transmit light but the ability to reflect light from their surface. More, the clean or polished the surface would be more light they would reflect.
Moreover, opaque minerals do not transmit light, they reflect it back into our eyes that is why we can see them. So, this correct.
Answer: nonmetallic; do not transmit
Explanation:
Derive an expression similar to the equation for the energy levels above for the single electron in He+ and Li2+ . Calculate the numerical values for the 1s levels (n = 1)?
Answer:
Explanation:
from Bohr's equation,
E = -Z²R/n²
R = 13.6 eV
Z = atomic number of element
for 1s energy level n= 1
E = -(Z)² x (13.6)/(1)²
E = -13.6Z²
calculating the numerical for the 1s energy levels for He+ and Li2+
- for He+
E = -13.6 * (2)² = -54.4eV
- for Li2+
E = -13.6 * (3)² = -122.4eV
Characteristics of this mineral: hardness of 3, three directions of cleavage (cleaves into rhombs), partially transparent, effervesces with dilute HCl without being pulverized into a fine powder.
Answer:
Calcite
Explanation:
Calcite is a mineral formed by calcium carbonate (CaCO3), class 05 of the Strunz classification, the so-called carbonate and nitrate minerals.
All members of this group crystallize in the trigonal system, have a perfect rhombohedral cleavage and exhibit a strong double refraction in transparent rhombohedra.
It presents a variety of shapes and colors. It is characterized by its low hardness, 3 on the Mohs scale, and by its high reactivity even with weak acids.
The best property to identify calcite is the acid test, since this mineral produces effervescence with acids. The reason for this is the following reaction:
CaCO3 + 2H + → Ca2+ + H2O + CO2 (gas)
The molecule that carries an amino acid to the ribosome for incorporation into a protein is ________.
Photovoltaic cells convert solar energy into electricity. Calculate the wavelength of light (in nm) required for mercury (Φ =7.22 × 10–19 J) to emit an electron. Then determine whether or not mercury could be used to generate electricity from the sun. Assume that most of the electromagnetic energy from the sun is in the visible region near 500 nm.
Answer:
275.3 nm is the wavelength of light required for mercury.
Mercury can not be used to generate electricity from the sun because wavelength at which mercury will emit an electron is smaller than 500 nm.
Explanation:
The wavelength of light required for mercury to emit an electron.
The wavelength of the radiation = [tex]\lambda [/tex]
Energy required fro mercury to to emit an electron = E
Energy required fro mercury to to emit an electron will the energy if the radiation = E' = [tex]7.22\times 10^{-19} J[/tex]
E' = E
To calculate the wavelength of light, we use the equation:
[tex]E=\frac{hc}{\lambda }[/tex]
where,
[tex]\lambda[/tex] = wavelength of the light
h = Planck's constant = [tex]6.626\times 10^{-34} Js[/tex]
c = speed of light = [tex]3\times 10^8m/s[/tex]
[tex]\lambda =\frac{hc}{E}[/tex]
[tex]=\frac{6.626\times 10^{-34} Js\times 3\times 10^8m/s}{7.22\times 10^{-19} J}[/tex]
[tex]\lambda =2.753\times 10^{-7} m=2.753\times 10^{-7}\times 10^ nm =275.3 nm[/tex]
Wavelength of the sun light in the visible region = 500 nm
500 nm > 275.3 nm
[tex]E\propto \frac{1}{\lambda }[/tex]
Less energy < more energy
So, this means that mercury can not be used to generate electricity from the sun.
The wavelength of light in nm is
275nmThe mathematical formula for wavelength[tex]\lambda = \frac{hc}{E}\\\\ \lambda = \frac{6.626*10^{-34} * 3*10^8}{7.22*10^{-19}}\\\\ \lambda = 2.7531856*10^{−7}\\\\ \lambda = 275nm [/tex]
No, the therhold energy is larger than the wavelength of sun, therefore, electricity will not be generated.
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The Mendeleev and Mosley periodic charts have gaps for the as-then-undiscovered elements. Why do you think the chart used by Mosley was more accurate at predicting where new elements would be placed?
Answer:
Henry Mosley' chart was more accurate because he used 'atomic number' as the organizing principle to organize elements in its right places.Whereas Mendeleeve organized elements according to their relative atomic mass and this was giving him some problem.
Mosley's periodic chart was more accurate at predicting the placement of new elements due to its use of atomic number, whereas Mendeleev's chart was based on atomic mass.
Explanation:Mendeleev and Mosley both contributed to the development of the periodic table. However, the chart used by Mosley was more accurate at predicting the placement of new elements because Mosley's chart was based on the concept of atomic number, while Mendeleev's chart was based on atomic mass.
Atomic number is the number of protons in an atom's nucleus, while atomic mass is the total mass of protons and neutrons in an atom. Mosley's chart arranged elements in order of increasing atomic number rather than atomic mass.
This arrangement allowed for a more accurate placement of elements, as it accounted for variations in atomic mass caused by differences in the number of neutrons. As a result, Mosley's chart was able to predict the placement of new elements more accurately than Mendeleev's chart.
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Which combination of formula, IUPAC name, and common name below is incorrect? Formula IUPAC Name Common Name (a) CHCl3 trichloromethane chloroform (b) CCl4 tetrachloromethane carbon tetrachloride (c) C6H5I iodobenzene phenyl iodide (d) CH3Cl chloromethane methyl chloride (e) CH2Cl2 dichloromethane methene chloride
Answer:
option (e), dichloromethane, methene chloride
Explanation:
(a) [tex]CHCl_3[/tex]
Common name: chloroform
IUPAC name: one carbon atom, therefore, root word is meth.
Its is saturated compounds, so add ane after root word.
Three chlorine atoms are present.
Therefore, IUPAC name: Trichloromethane
(b) [tex]CCl_4[/tex]
Common name: Carbon tetrachloride
IUPAC name: one carbon atom, therefore, root word is meth.
Its is saturated compounds, so add ane after root word.
Four chlorine atoms are present, chlorine atoms are named as prefixes.
Therefore, IUPAC name: tetrachloromethane
(c) [tex]C_6H_5I[/tex]
Common name: Phenyl iodide
IUPAC name:
The given compound is an aryl halides. Aryl haildes are named as haloarenes. The prefix halo is placed before aromatic hydrocarbon. Here, prefix is iodo and aromatic hydrocarbon is benzene.
Therefore, IUPAC name of the compound is iodobenzene.
(d) [tex]CH_3Cl[/tex]
Common name: Methyl chloride
IUPAC name: one carbon atom, therefore, root word is meth.
Its is saturated compounds, so add ane after root word.
One chlorine atom is present.
Therefore, IUPAC name: chloromethane
(e) [tex]CH_2Cl_2[/tex]
Common name: Methylene chloride
IUPAC name: one carbon atom, therefore, root word is meth.
Its is saturated compounds, so add ane after root word.
Two chlorine atoms are present, chlorine atoms are named as prefixes.
Therefore, IUPAC name: dichloromethane.
Therefore, the correct option is option (e), dichloromethane, methene chloride
When an ionic compound such as sodium chloride (NaCl) is placed in water, the component atoms of the NaCl crystal dissociate into individual sodium ions (Na+) and chloride ions (Cl-). In contrast, the atoms of covalently bonded molecules (e.g., glucose, sucrose, glycerol) do not generally dissociate when placed in aqueous solution. Which of the following solutions would be expected to contain the greatest number of solute particles (molecules or ions)?
Answer: solutions that would be expected to contain the greatest number of solute particles (molecules or ions) is
1 L of 1.0 M NaCl
Aspirin, like many pharmaceutical drugs, can access the cell because it is a weak acid. This occurs because Choose one: A. it is carried by water during osmosis. B. it is a small uncharged molecule. C. it disrupts the membrane enough to squeeze through. D. as a weak acid it can cross the membrane when in its uncharged form.
Answer:
Correct answer is (D). as a weak acid it can cross the membrane when in its uncharged form.
Explanation:
Aspirin (acetylsalicylic acid, ASA) is an analgesic and anti-inflammatory agent use in the treatment of gentle to moderate pain, inflammation and fever. It is absorb in the stomach and intestine in an unchanged form.
Maleic acid is an organic compound composed of 41.39% , 3.47% , and the rest oxygen. If 0.378 mole of maleic acid has a mass of 43.8 g, what are the empirical and molecular fomulas of maleic acid?
Answer:
Empirical CHO
molecular C4H4O4
Explanation:
From the question, we know that it contains 41.39% C , 3.47% H and the rest oxygen. To get the % composition of the oxygen, we simply add the carbon and hydrogen together and subtract from 100%.
This means : O = 100 - 41.39 - 3.47 = 55.14%
Next is to divide the percentage compositions by their atomic masses.
C = 41.39/12 = 3.45
O = 55.14/16 = 3.45
H = 3.47/1 = 3.47
Now we divide by the smallest value which is 3.45. We can deduce that this will definitely give us an answer of 1 all through as the values are very similar.
Hence the empirical formula of Maleic acid is CHO
Now we go on to deduce the molecular formula.
To do this we need the molar mass. I.e the amount in grammes per one mole of the compound.
Now we can see that 0.378mole = 43.8g
Then 1 mole = xg
x = (43.8*1)/0.378 = 115.87 = apprx 116
[CHO]n = 116
(12 + 1 + 16]n = 116
29n = 116
n = 116/29 = 4
The molecular formula is thus C4H4O4
Suppose 0.410 kg of hexane are burned in air at a pressure of exactly 1 atm and a temperature of 13.0 °C. Calculate the volume of carbon dioxide gas that is produced.Round your answer to 3 significant digits.
Answer:
The answer is 671 litres of carbon dioxide is produced from 0.410 kg of hexane
Explanation:
We first write a balanced reaction for the complete combustion of hexane thus
The stoichiometry of the cumbustion of hexane in air is
2C6H14(g)+18O2(g)→12CO2(g)+14H2O(l) or
C6H14(g)+9O2(g)→6CO2(g)+7H2O(l)
From the above reaction it is observed that one mole of hexane burns completely in the presence of oxygen to produce 6 moles of carbon dioxide
Therefore we calculate the nuber of moles of hexane present in the sample thus
Mass hexane of sample = 0.41 kg
Molar nass of hexane = 86.18 g/mol
number of moles of hexane = (mass of hexane)/(molar mass of hexane) = (0.41×1000)/86.16 = 410/86.16 = 4.76 moles
As we have seen from the chemical reaction, 1 mole of H6H14 produces 6 moles of CO2 hence 4.76 moles of Hexane produces
4.76×6 moles of CO2 which is 28.55 moles of CO2
From the question we have the temperature and the pressure of the production of CO2 as
Temperature of reaction = 13° C converting to kelving gives= 13+273.15 = 286.15 K
and pressure = 1 atmosphere or 101325 Pa
13.0∘C=13.0∘C+273.15=286.15 K
The volume of the produced CO2 can be calculated using the combined ideal gas equation given by
P×V=n×R×T where
Here
P = Gas pressure (of CO2 )
V = Volume (of the CO2)
n = number of moles of gas (CO2) present
R = universal gas constant, equal to 0.0821 atm× L/(mol× K )
T = absolute temperature in Kelvin
Thus we have
1×V = 28.55×0.0821×286.15 or V = 670.76L
Rounding up the answer to 3 significant digits we have
670.76L ≅ 671L
671 litres of carbon dioxide is produced from 0.410 kg of hexane