Volume of gases

Question 1

How is the volume of a gas calculated

Answer 1

Molar volume x mass/moles of gas = volume of gas

Question 2

If each gas is the same temperature, has the same pressure and is under the same volume, what factor of each gas’ quantity is equal

Answer 2

Number of moles

Question 3

what is the volume of any mole at room temp/pressure

Answer 3

24dm^3

Question 4

What is the molar mass and what is its value

Answer 4

A) Volume occupied by 1 mole of gas at room temp/pressure

B) 24dm^3

Question 5

How is the number of moles in an element calculated

Answer 5

Mass/Ar

Question 6

How is the volume of hydrogen produced calculated when 4.6 g of sodium reacts completely with excess water:

2Na(s) + 2H2O(l) —> 2NaOH(aq) + H2(g)

(3 steps: mole, ratio, volume)

Answer 6

1) calculate moles in sodium: 4.6/23 = 0.2
2) calculate simplified mole ratio between sodium and hydrogen: 0.2:0.1 = 2:1
3) calculate volume of hydrogen: 0.1 x 24dm^3 = 2.4dm^3

Question 7

How much LiOH is needed to absorb 12dm^3 of carbon dioxide from the atmosphere:

2LiOH(s) + CO2(g) —> Li2CO3(s) + H2O(l)

(Moles, ratio, mass)

Answer 7

1) calc moles in CO2: vol/molar vol = moles so 12dm^3/24dm^3 = 0.5mol
2) simplify ratio between LiOH and CO2: 1:0.5 = 2:1
3) calc mass of LiOH: Mr x moles = mass so 24 x 1 = 24g