Which element do scientists use to standardize molar masses?
A) Carbon
B) Hydrogen
C) Iron
D) Oxygen

Answer:

positive

Explanation:

lost of negative electron leaves one more positive charges than negative charges.

Answer:

Histamine is a protein produced by mast cells in the body. It plays a very important role in the immune system of the body. Histamine is released in the body when affected by an allergen, e.g, pollen or animal dander. The immune system of the body will respond to such allergen by making more mucus in the nose by releasing histamine. There will be sneezing, itching, coughing and runny nose in response. This is a basic defense of the body's immune system to not enter any particle inside the body.

There are 12.052 ×10²³ atoms in 54 g of aluminium according to the concept  of Avogadro's number.

Avogadro's number is defined as a proportionality factor which relates number of constituent particles with the amount of substance which is present  in the sample.

It  has a SI unit of reciprocal mole whose numeric value is expressed in reciprocal mole which is a dimensionless number and is called as Avogadro's constant.It relates the volume of a substance with it's average volume occupied by one of it's particles .

According to the definitions, Avogadro's number depend on determined value of mass of one atom of those elements.It bridges the gap between macroscopic and microscopic world by relating  amount of substance with number of particles.

Number of atoms can be calculated using Avogadro's number as  follows: mass/molar mass×Avogadro's number

Substituting the values in the formula,54/26.98×6.022×10²³=12.052×10²³ atoms .

Hence, there are 12.052×10²³ atoms in 54 g of aluminium.

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Final answer:

To find the number of atoms in 54.0 g of aluminum, you need to convert the mass of aluminum to moles, and then use Avogadro's number to convert moles to atoms.

Explanation:

To find the number of atoms in 54.0 g of aluminum, you need to convert the mass of aluminum to moles, and then use Avogadro's number to convert moles to atoms.

The molar mass of aluminum is 26.98 g/mol, so you can calculate the number of moles by dividing the mass of aluminum by its molar mass:

54.0 g Al / 26.98 g/mol = 2.001 moles Al

Finally, you can determine the number of atoms by multiplying the number of moles by Avogadro's number (6.022 × 10²³ atoms/mol):

2.001 moles Al * 6.022 × 10^23 atoms/mol = 1.204 × 10²⁴ atoms

The car would need approximately 7.73 gallons of gasoline for a 3.0-hour trip at a speed of 70 mi/h, and fuel efficiency of 11km/L.

To calculate how many gallons of gas are needed for a 3.0-hour trip, we must first figure out the total distance the car travels. With a speed of 70 miles per hour (mi/hr), the car would cover 70 mi/hr x 3 hours = 210 miles.

Next, we will have to convert miles to kilometers since the fuel consumption rate is given in kilometers per liter (km/L). So, 210 miles ≈ 321.87 kilometers (using conversion factor 1 mile ≈ 1.60934 kilometers).

The car uses gasoline at a rate of 11 kilometers per liter. Therefore, it would consume 321.87 kilometers ÷ 11 km/L ≈ 29.26 liters of gas.

Finally, since gas is usually measured in the U.S. in gallons, we need to convert liters to gallons. 29.26 liters ≈ 7.73 gallons (using conversion factor 1 liter ≈ 0.264172 gallons).

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Answer:

                       1.42 g/mL

Explanation:

                    The mass per unit volume is called as density. It is an intensive property and its value doesn't depend upon the amount of a substance.

It is given as,

                                   Density  =  Mass / Volume

Data Given:

Mass of Liquid + Flask  =  163.4 g

Volume of Liquid = 5.98 mL

Mass of empty Flask = 154.9 g

Mass of Liquid  = 163.4 g - 154.9 g =  8.5 g

Formula Used:

                     Density  =  Mass / Volume

                     Density  =  8.5 g / 5.98 mL

                     Density  =  1.42 g/mL

368.92 g of HCOOH could be formed.

Explanation:

First we have to write the balanced equation as,

CH₃OH + O₂ → HCOOH + H₂O

Here the question said that 8.02 mol of CH₃OH and 15.49 mol of O₂.

In the above reaction methanol and oxygen is used in 1:1 ratio, but the moles are lesser in case of methanol, so CH₃OH  is the limiting reagent.

Now by making use of 8.02 moles of methanol, we can produce 8.02 mol of HCOOH.

Molar mass of HCOOH is 46 g/mol.

So mass of HCOOH formed is moles ×molar mass of HCOOH.

8.02 moles × 46 g/mol = 368.92 g of HCOOH could be formed.

Answer: The earth is only several thousands years old is not true.

Explanation:The age of Earth is estimated to be 4.54 ± 0.05 billion years .

This age may represent the age of Earth's accretion, or core formation, or of the material from which Earth formed.

Answer:

The volume is 214, 3 ml

Explanation:

We calculate the weight of 1 mol of  NH4OH:

Weight  1 mol NH4OH=  Weight N + (Weight H) * 5 + Weight 0

Weight  1 mol NH4OH= 14g + 1 g* 5 + 16g = 35 g/mol

1 mol NH4OH-----35 g

0,6mol NH4OH----X=(0,6mol NH4OHx 35 g)/1 mol NH4OH= 21 g

We have 0,6 mol in 1000ml of solution (0,600 M)

21g NH4OH-----------1000ml

4,50 g NH4OH------x= (4,50 g NH4OH  x 1000ml)/21 g NH4OH= 214, 2857143 ml

Answer:

[tex]\large \boxed{\text{8.00 mol}}[/tex]

Explanation:

We will need a balanced chemical equation with masses, moles, and molar masses.

1. Gather all the information in one place:

Mᵣ:                  18.02

            2Na + H₂O ⟶ 2NaOH + H₂

m/g:                72.0  

2. Moles of H₂O

[tex]\text{Moles of H$_{2}$O} = \text{72.0 g H$_{2}$O} \times \dfrac{\text{1 mol H$_{2}$O}}{\text{18.02 g H$_{2}$O}} = \text{3.996 mol H$_{2}$O}[/tex]

3. Moles of Na

The molar ratio is 2 mol Na/1 mol H₂O.

[tex]\text{Moles of Na} = \text{3.996 mol H$_{2}$O} \times \dfrac{\text{2 mol Na}}{\text{1 mol H$_{2}$O}} = \textbf{8.00 mol Na}\\\\\text{The water will react with $\large \boxed{\textbf{ 8.00 mol}}$ of Na}[/tex]

Final answer:

To find out how many moles of sodium would react with 72.0 grams of water, we calculate moles of water using its molar mass and then apply the stoichiometry of the reaction between sodium and water. We conclude that 4 moles of sodium would react with 72.0 grams of water.

Explanation:

The question appears to contain a typo and seems to ask how many moles of sodium would react with 72.0 grams of water.

Molar mass of water (H₂O) is approximately 18.02 g/mol. Therefore, to find out how many moles of water we have in 72.0 grams, we use the formula:

moles of H₂O = mass of H2O / molar mass of H₂O

moles of H₂O = 72.0 g / 18.02 g/mol = 4 moles of H₂O

The reaction between sodium (Na) and water (H₂O) typically forms sodium hydroxide (NaOH) and hydrogen gas (H2). The balanced chemical equation for this reaction is:

2Na + 2H₂O → 2NaOH + H2

From the balanced reaction, we can see that 2 moles of Na are required to react with 2 moles of H₂O. This means, to react with 4 moles of H₂O, we would need 4 moles of Na.

Resulting pressure is 13.6 atm.

Explanation:

Using Ideal gas equation, we can find the pressure of the gases formed in the reaction.

PV = nRT

Number of moles, n = given mass / molar mass = 20 g / 18 g/mol

                           = 1.11 moles

Volume, V = 2 L

Temperature, T = 25°C + 273 = 298 K

R = gas constant = 0.08206 L atm K⁻¹ mol⁻¹

P = nRT/V

 = 1.11×0.08206 ×298 / 2

 = 13.6 atm  

Answer:

                      36.46 g of HCl

Explanation:

                    The balance chemical equation for given single replacement reaction is as follow;

                              Mg + 2 HCl → MgC₂ + H₂

Step 1: Calculate Moles of HCl required:

According to equation,

                   1 mole of Mg reacted with  =  2 moles of HCl

So,

                0.5 moles of Mg will react with  =  X moles of HCl

Solving for X,

                     X =  0.5 mol × 2 mol / 1 mol

                      X =  1 mol of HCl

Step 2: Calculate Mass of HCl as;

                    Moles  =  Mass / M.Mass

Or,

                    Mass  =  Moles × M.Mass

                    Mass  =  1 mol × 36.46 g/mol

                   Mass =  36.46 g of HCl

Final answer:

To react 0.50 moles of magnesium completely with HCl, 36.46 grams of HCl are required, based on the stoichiometric ratio from the balanced chemical equation.

Explanation:

To find the number of grams of HCl needed to react completely with 0.50 moles of magnesium, we must refer to the balanced chemical equation Mg(s) + 2HCl(aq) → MgCl₂(aq) + H₂(g). According to the equation, 1 mole of magnesium reacts with 2 moles of HCl. Therefore, 0.50 moles of magnesium will require 1 mole of HCl (0.50 moles Mg × 2 moles HCl/mol Mg = 1 mole HCl).

The molar mass of HCl is approximately 36.46 g/mol. Now, we can calculate the mass of HCl needed:

Mass of HCl = moles HCl × molar mass of HCl = 1 mole × 36.46 g/mol = 36.46 grams of HCl.

Answer: 85.8 g AlCl3

Explanation:

Convert molecules of AlCl3 to moles using the Avogadro's number

Convert moles of AlCl3 to mass using its molar mass.

3.913x10²³ molecules AlCl3 x 1mole AlCl3 / (6.022x10²³ molecules AlCl3) X 132g AlCl3/ 1 mole AlCl3

= 85.8 g AlCl3

Fungi play a crucial role in the food web shown as they are decomposers. They break down dead organic matter, such as dead plants and animals, and recycle the nutrients back into the ecosystem.

Microbes, or microorganisms, play important roles in food webs and ecosystem functioning. They can be found at all trophic levels of the food web, from primary producers to top predators, and their activities have significant impacts on the cycling of energy and nutrients.

In this food web, the fungus likely feeds on dead organic matter produced by the other organisms in the ecosystem, such as the sloth and the fruit bat.

This recycling of nutrients helps to maintain the balance of the ecosystem and supports the growth of other organisms in the food web, such as the strangler fig which may benefit from the nutrients provided by the decomposing organic matter.

Without decomposers like fungi, dead organic matter would accumulate in the ecosystem, leading to nutrient depletion and the eventual collapse of the food web.

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Answer:

yes

Explanation:

Hydroelectric energy is a renewable energy source that uses the potential energy of water to generate electricity. It's a significant contributor to renewable energy consumption but does come with environmental concerns that need to be addressed.

Yes, hydroelectric energy is considered a renewable energy source. Hydroelectric power plants use the potential energy stored in water held in dams or flowing in rivers to generate electricity. When water is released from the dam, it flows through turbines, converting potential energy into kinetic energy, which is then used to generate electricity.

This process is renewable because it relies on the water cycle, which is a natural and continuous process on Earth. Water evaporates, forms clouds, and then falls as precipitation, continually replenishing the water in rivers and reservoirs. Hydroelectric power does not produce direct pollutants, making it a clean energy source.

While hydroelectric power is a significant portion of renewable energy consumption, accounting for about 35% of the United States' renewable energy, it is not without environmental concerns. Dams can disrupt local ecosystems and obstruct the migratory paths of fish. However, with proper management and environmental considerations, such as fish ladders, these impacts can be mitigated, allowing hydroelectric power to remain a valuable part of our renewable energy portfolio.

Answer:

They all vibrate, but they all move differently.

Explanation:

Similarities: They all consist of particles and vibrate, just at different frequencies.

Differences: The particles in solids move slowly and vibrate. In liquids, they move a bit quicker and slide past one another. They will also take the shape of the container they're in. In gases, they move freely at high speeds and also taking the shape of the container.

Hope this helped! :)

If the applied force on a car is cut in half, the acceleration is also halved, as acceleration is directly proportional to force.

Based on Newton's second law of motion, acceleration (a) is directly proportional to the net applied force (Fnet) and inversely proportional to the mass (m) of the object, which is expressed by the formula a = Fnet/m. From the question, if the applied force to a car is cut in half, the acceleration would also be reduced by half, assuming the mass of the car remains constant. If the initial acceleration was a, then the new acceleration would be a/2 when the force is halved.

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Answer:

Direct relationship.

Explanation:

Answer: B. Pressure, temperature, and volume

Explanation:

I took the test

hope this helped

The three physical properties of gases are pressure, temperature and volume and the correct option is option B.

Gasses do not possess any definite volume or shape. They totally fill all the space accessible to them. The characteristic or properties of gases to fill the available volume within a container is the result of the freedom that gas particles have to move everywhere in the accessible space.

Gases are physical properties of mark sensitivity of volume change with the change of temperature and pressure.

Thus the gases are generally concerned with the relations among four properties, namely mass, pressure, volume, and temperature.

Therefore, The three physical properties of gases are pressure, temperature and volume and the correct option is option B.

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Answer:

A. The electric energy is due to the protons’ charges and positions within an electric field, so their energy is a form of potential energy.

Explanation:

Proton is subatomic particle with positive charge. Things with charge will pull the opposite charge and repel/push the same charge. The closer their position, the higher the energy will be. It should be potential energy since your location(how close it is) determine how strong the energy.

It's not thermal or kinetic energy since this doesn't involve any movement yet.

NaCl, H₂O₂ and CaF₂ are electrolytes, whereas CO₂ and Al₂O₃ are non-electrolytes.

Explanation:

An electrolyte is a liquid or solution contains ions which may be decomposed by means of electrolysis.

NaCl dissociates into Na⁺ and Cl⁻ ions in solution is an electrolyte.

CO₂ is a Non-electrolyte.

Al₂O₃ is a Non-electrolyte.

H₂O₂ is an electrolyte

CaF₂ is an electrolyte

Final answer:

The compounds NaCl are electrolytes because they are ionic and can dissociate into ions in solution or when molten. CO are molecular compounds and do not dissociate into ions when dissolved in water, making them non-electrolytes.

Explanation:

The question is asking whether certain compounds are electrolytes or non-electrolytes. An electrolyte is able to conduct electricity when dissolved in water because it separates into ions that are mobile and can move from one electrode to the other. In contrast, a non-electrolyte does not dissociate into ions and hence does not conduct electricity in solution.

Answer:

[tex]\large \boxed{\text{4650 nm}}[/tex]

Explanation:

The second line in the Pfund series corresponds to a transition from n = 7 to n = 5.

To calculate the wavelength of the transition, we can use the Rydberg equation:

[tex]\dfrac{1}{\lambda} = R_{H}\left ( \dfrac{1 }{n_{1}^{2}} - \dfrac{1 }{n_{2}^{2}} \right )[/tex]

where

[tex]R_{H} = 1.097 \times 10^{7} \text{ m}^{-1}[/tex]

If n₁ = 5 and n₂ = 7

[tex]\begin{array}{rcl}\dfrac{1}{\lambda} & = & 1.097 \times 10^{7} \text{ m}^{-1}\left ( \dfrac{1 }{5^{2}} - \dfrac{1 }{7^{2}} \right )\\\\ & = & 1.097 \times 10^{7} \text{ m}^{-1}\left ( \dfrac{1 }{25} - \dfrac{1 }{49} \right )\\\\ & = & 1.097 \times 10^{7} \text{ m}^{-1}\left ( \dfrac{49 - 25 }{49 \times25}\right )\\\\& = & 1.097 \times 10^{7} \text{ m}^{-1}\left ( \dfrac{24 }{1225}\right )\\\\ & = & 2.149 \times 10^{7}\text{ m}^{-1}\\\end{array}\\[/tex]

[tex]\begin{array}{rcl}\lambda & = & \dfrac{1}{2.149 \times 10^{7}\text{ m}^{-1}}\\\\ & = & 4.65 \times 10^{-6} \text{ m}\\ & = & \mathbf{4650} \textbf{ nm}\\\end{array}\\\text{The wavelength of the line is $\large \boxed{\textbf{4650 nm}}$, which is in the $\textbf{infrared region}$}.[/tex]

The calculated wavelength for the second line in the Pfund series is 4.65 x 10^-6 m (4650 nm), positioning it within the infrared spectrum.

Rydberg Equation:

The Rydberg equation is employed to calculate the wavelength (λ) of light emitted or absorbed during electronic transitions in hydrogen-like atoms.

"1/λ = RH (1/n₁² - 1/n₂²)"

Given Values:

We are given the Rydberg constant (RH) as "1.097 x 10^7 m^-1" and the principal quantum numbers (n₁ = 5 and n₂ = 7).

Substitute Values:

Substituting the known values into the Rydberg equation:

"1/λ = 1.097 x 10^7 (1/5² - 1/7²)"

Evaluate Exponents:

Calculating the squares in the denominators:

"1/λ = 1.097 x 10^7 (1/25 - 1/49)"

Find Common Denominator:

Combining the fractions over a common denominator (1225):

"1/λ = 1.097 x 10^7 (49 - 25)/1225"

Combine Terms:

Simplifying the expression:

"1/λ = 1.097 x 10^7 (24/1225)"

Calculate:

Performing the multiplication:

"1/λ = 2.149 x 10^7 m^-1"

Reciprocal to Find Wavelength:

Taking the reciprocal to find the wavelength:

"λ = 1/(2.149 x 10^7)"

Final Result:

Converting the numerical result to scientific notation:

"λ = 4.65 x 10^-6 m"

= 4650nm

This detailed calculation ensures a comprehensive understanding of each step involved in determining the wavelength.

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Answer:

                   T₁  =  194 K

Solution:

Data Given:

                 Initial Temperature  =  T₁  =  ??

                 Final Temperature  =  T₂  =  465 K

                 Initial Pressure  =  P₁  =  18.7 psi

                 Final Pressure  =  P₂  =  20.2 psi

                 Initial Volume  =  V₁  =  0.475 L

                 Final Volume  =  V₂  =  1.054 L

Formula Used:

Let's assume that the hydrogen gas in balloon is acting as an Ideal gas, the according to Ideal Gas Equation,

                 P V  =  n R T

where;  R  =  Universal Gas Constant  =  0.082057 atm.L.mol⁻¹.K⁻¹,

Taking number of moles and R constant we can have following formula for initial and final states,

                P₁ V₁ / T₁  =  P₂ V₂ / T₂

Solving for T₁,

                T₁  =  P₁ V₁ T₂ / P₂ V₂

Putting values,

                T₁  =  (18.7 psi × 0.475 L × 465 K) / (20.2 psi × 1.054 L)

               T₁  =  194 K

Answer:

194 K

Explanation:

Answer:

8 electrons

Explanation:

For the two atoms to have an octet configuration, they must share

8 electrons. Two of the atom with six valence electron will bond with one of the atom with four valence electrons. This is clearly seen when carbon react will sulphur to form carbon disulfide. They form covalent double bond (S=C=S)

Answer:

u gotta have the volume of it

Explanation:

Answer:

e65

Explanation:

cadhff

It is a radio wave

Explanation:

The energy of an electromagnetic waves is related to its frequency by the equation:

[tex]E=hf[/tex]

where

h is the Planck constant

f is the frequency of the wave

We notice that the energy of an electromagnetic wave is proportional to its frequency. This means that waves with higher frequencies, such as gamma rays, x-rays, are more energetic, while waves with lower frequencies, such as microwave and radio waves, are the less energetic.

In this case, we want to find the frequency of a wave with energy

E = 0.000001 eV

Converting into Joules,

[tex]E=1\cdot 10^{-6} eV \cdot 1.6\cdot 10^{-19} J/eV=1.6\cdot 10^{-25} J[/tex]

Solving for the frequency,

[tex]f=\frac{E}{h}=\frac{1.6\cdot 10^{-25}}{6.63\cdot 10^{-34}}=2.4\cdot 10^8 Hz = 240 MHz[/tex]

Which falls in the range of frequency of radio waves.

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Answer:

Radio waves,because a radio wave has a longer wavelength than both infrared and X-rays, so it has less energy

Explanation:



Answer:

A and i think D

Explanation:

Answer:

Can confirm that its A and D.

Explanation:

ape-x

Answer:

5878.6 j

1.405 cal

Explanation:

Given data:

Specific heat of fat = 0.45 cal/g.°C or 1.9 j/g.°C

Density of fat = 30.94 g/cm³

Initial temperature = 25°C

Final temperature = 35°C

Energy needed = ?

Volume of fat = 10 cm³

Solution:

First of all we will calculate the mass of fat from given density and volume.

d = m/v

30.94 g/cm³ = m/ 10 cm³

m = 30.94 g/cm³ ×  10 cm³

m = 309.4 g

Now we will calculate the energy needed for fat.

Q = m.c. ΔT

Q = amount of heat absorbed or released

m = mass of given substance

c = specific heat capacity of substance

ΔT = change in temperature

ΔT = T2 - T1

ΔT =  35°C -  25°C

ΔT =  10°C

Q = m.c. ΔT

Q = 309.4 g . 1.9 j/g.°C . 10°C

q = 5878.6 j

In calories,

5878.6 / 4184 = 1.405 cal

The energy required to heat 10cm3 of fat from 25°C to 35°C is calculated using the specific heat formula. The calculations in calories and joules are 42.3 cal and 178.6 Joules respectively.

To calculate the amount of energy needed to heat 10 cm3 of fat from 25 °C to 35 °C, we have to understand the concept of specific heat, which is the energy required to raise the temperature of 1 gram of a substance by 1 °C. Here, we are dealing with the substance fat, which has a specific heat of 0.45 cal/(g ⋅ °C) or 1.9 J/g °C and a density of 0.94 g/cm3.

First, determine the mass of the fat using the formula mass = volume × density. Here, volume is 10 cm3 and density is 0.94 g/cm3, which gives us a mass of 9.4 g. The change in temperature (ΔT) we need is from 25°C to 35°C, hence ΔT = 35 - 25 = 10 °C.

The energy required can then be calculated using the formula energy = mass × specific heat × ∆T. For calories, the calculation is energy = 9.4g × 0.45 cal/(g °C) × 10 °C = 42.3 cal. For Joules, the calculation is energy = 9.4 g × 1.9 J/(g °C) × 10°C = 178.6 Joules.

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Answer:

             The complete chemical equation is as;

                                          C + O₂   →   CO₂

Explanation:

                    According to law of mass conservation the mass in isolated system can neither be created nor be destroyed. Applying this law to given synthesis reaction means that,

               (i) If there is one carbon atom on left hand side of the equation (reactant side) then there must be on e carbon on right hand side (product side) of the equation.

                (ii) If there are two oxygen atoms on left hand side of the equation (reactant side) then there must be two oxygen atoms on right hand side (product side) of the equation.

Hence, from equation it is proved that it obeys the said law and the number of atoms on both side are equal i.e.

                           Reactant Side                     Product Side

Carbon                          1                                          1

Oxygen                          2                                         2