Avogadro's Law and the Ideal Gas Law

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Multiple Choice

Gases of the same volume contain the same number of molecules.  This is the description of:

• Boyle's law

• Dalton's law

• Charles' law

• Avogadro's law

Multiple Choice

At constant temperature and pressure, the volume of a gas is directly proportional to the ________________.

• pressure of the gas

• temperature of the gas

• number of moles of the gas

• velocity of the gas

Multiple Choice

What must be held constant when applying Avogadro's law?

• pressure and temperature

• volume and temperature

• number of moles and temperature

• volume and number of moles

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Sample Problem: Avogadro’s Law

A balloon has been filled to a volume of 1.90 L with 0.0920 mol of helium gas. If 0.0210 mol of additional helium is added to the balloon while the temperature and pressure are held constant, what is the new volume of the balloon?

Step 1: List the known quantities and plan the problem.

Known: Unknown:

V₁ = 1.90 L V₂ = ? L

n₁ = 0.0920 mol

n₂ = 0.0920 + 0.0210 = 0.1130 mol

Step 2: Solve. First, rearrange the equation algebraically to solve for V₂.

Make sure you know how to rearrange the equation!!

Multiple Choice

If 3.25 mol of Ar occupies 100. L at a particular temp and pressure, what volume does 14.15 mol of Ar occupy under same condition?

^{Use scratch paper and a calculator!}

• 435 L

• 225 L

• 100 L

• 522 L

Multiple Choice

A scientist records 8.0 moles of gas. The scientist does not check the pressure of this gas. At a later time the scientist measures the volume of gas to be 150 ml and the new number of moles of gas to be 48 what was the original volume of the gas?

_{Use scratch paper and a calculator!}

• 25 ml

• 0.39 ml

• 2.56 ml

• 2.5 ml

Multiple Choice

A 10. ml balloon is not tied all the way and 5.0 of the original 20. moles of gas escape before the gas is tied.What is the new volume of the gas?

_{Use scratch paper and a calculator!}

• 30 ml

• 10 ml

• 7.5 ml

• 2.5 ml

Multiple Choice

A scientist records the volume of gas in a bubble to be 43 mL The scientist determines that the bubble contains 8 moles of oxygen. The scientist checks in on the bubble later to find that the volume has expanded to 129 ml how much oxygen is in the bubble now?

_{Use scratch paper and a calculator!}

• 2.4 moles

• 24 moles

• 240 moles

• 2400 moles

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^{Check out these different ways to REARRANGE the equation depending on what variable you are solving for.}

Multiple Choice

If the pressure exerted by a gas at 25 degrees C in a volume of 0.044 L is 3.81 atm, how many moles of gas are present?

_{Use scratch paper and a calculator!}

• .002766 mole

• .0069 mol

• 2.766 mol

• 9.887 mol

Multiple Choice

In order to solve gas law calculations, temperature must be measured in:

• Fahrenheit

• Celsius

• Kelvin

• It doesn't matter 

Multiple Choice

At what temperature will 0.654 moles of neon gas occupy 12.30 liters at 1.95 atmospheres?

_{Use scratch paper and a calculator!}

• 427 K

• 447 K

• 437 K

• 457 K

Multiple Choice

Calculate the volume that a 0.323-mol sample of a gas will occupy at 265 K and a pressure of 0.900 atm.

_{Use scratch paper and a calculator!}

• 7.18 L 

• 7.81 L

• 4.63 L

• 4.36 L

Multiple Choice

Choose the correct set of variables to solve the following problem: What is the volume of a balloon if it contains 3.2 moles of helium at a temperature of 20⁰C and 1.2 atm?

• P = x (unknown), V = 3.2 mol, n = 1.2 atm, T = 20⁰C K

• P = 1.2 atm, V = 3.2 mol, n = 20⁰C, T = x (unknown)

• P = 293 K, V = 3.2 mol, n = x (unknown), T = 1.2 atm

• P = 1.2 atm, V = x (unknown), n = 3.2 mol, T = 293 K

Multiple Choice

What does the variable "n" represent in the ideal gas law?

• pressure

• volume

• moles

• the gas constant

• temperature

Multiple Choice

In an ideal gas, if everything else is held constant, doubling the volume will ________ the pressure.

• double

• halve

• not affect

• eliminate

Multiple Choice

In an ideal gas, if everything else is held constant, tripling the pressure will ________ the Kelvin temperature.

• triple

• cut into a third

• not affect

• equal