DF 8 - Gas Volumes

Question 1

What are the number of molecules in one mole of gas?

Answer 1

6.02x10^23 (Avagadro’s constant)

Question 2

What is the rule for equal volumes of gases?

Answer 2

At the same temperature and pressure, they contain an equal number of molecules

Question 3

Why do equal volumes of gases at the same temperature and pressure contain an equal number of molecules?

Answer 3

• The number of molecules in one mole of gas is the same
• The molecules in a gas are very far apart compared to the actual size of each molecule, so there is a negligible effect on the total volume

Question 4

Define “molar volume”

Answer 4

Volume occupied by one mole of any gas at a particular temperature and pressure

Question 5

What is the molar volume of any gas at standard temperature and pressure?

Answer 5

24.0dm^3

Question 6

What is the formula for calculating the number of moles in a gas?

Answer 6

volume/molar volume (they must be the same unit)

Question 7

What is the ideal gas equation?

Answer 7

PV=nRT

Question 8

What does the “P” stand for in the ideal gas equation and what are its units?

Answer 8

Pressure - pa (pascals)

Question 9

What does the “V” stand for in the ideal gas equation and what are its units?

Answer 9

Volume - m^3

Question 10

What does the “R” stand for in the ideal gas equation and what is it?

Answer 10

Gas constant - 8.314JK-1mol-1

Question 11

What units of temperature are used in the ideal gas equation?

Answer 11

K

Question 12

How could a gas syringe be used to calculate the volume of gas produced in a reaction?

Answer 12

By attaching it to the opening of a reaction vessel

Question 13

What shows a reaction has finished?

Answer 13

When there is no further change in gas volume

Question 14

What is the setback of a gas syringe?

Answer 14

It only shows total volume, not individual gas volumes