Question

2. A 0.208 g sample of carbon dioxide, CO2, has a volume of 527 mL and a pressure of 483 mmHg . What is the temperature of the gas in kelvins? Express your answer to three significant figures.

3.When sensors in a car detect a collision, they cause the reaction of sodium azide, NaN3, which generates nitrogen gas to fill the air bags within 0.03 s. 2NaN3(s)→2Na(s)+3N2(g) How many liters of N2 are produced at STP if the air bag contains 139 g of NaN3? Express your answer with the appropriate units

Answer 1

PV = nRT Ideal gas equation

R = gas constant ( 0.082 L atm / mol. K)

2)

T = PV / nR

Molar mass of CO2 = 44 g/mol

So moles of CO2 = 0.208 g/ 44 g/mol => 0.0047 mol

V = 527 mL or 0.527 L

P = 483 mmHg * 1 atm / 760 mmHg => 0.6355 atm

T = 0.6355 atm * 0.527 L / ( 0.0047 mol * 0.082 L atm / mol. K)

T = 869 K

2) 2 NaN3 (s) ---> 2Na + 3N2

2 mol of NaN3 will form 3 mol of N2

Mole of NaN3 = 139 g/65 g/mol => 2.138 mol of NaN3

So moles of N2 = 2.138 * (3/2) => 3.207 mol of N2

STP is 1 atm P and 273.15 K

V = nRT /P

V = 3.207 mol * 0.082 L atm / mol. K * 273.15 K / 1 atm

V = 71.84 L