Question

Please answer ALL 3 questions and provide explanations :)

4. A given mass of oxygen at room temperature occupies a volume of 500.0 mL at 1.50 atm pressure. What will be the pressure if the volume is reduced to 150.0 mL?

5. Gases are sold in large cylinders for laboratory use. What pressure, in atmospheres, will be exerted by 2,500 g of oxygen gas (O₂) when stored at 22°C in a 40.0 L cylinder?

6. Consider the following reaction at STP:

CuO(s) +H₂(g) -> Cu(s) + H₂O(g)

If 40.0 g of CuO react with an excess of H₂, how many liters of H₂O will be produced?

Answer 1

4) from ideal gas equation

P1V1 = P2V2

P1 = 1.5 atm

V1 = 500 ml

P2 = ?

v2 = 150 ml

500*1.5 = P2*150

P2 = 5 atm

5) from ideal gas equation

   PV = nRT

P = pressure = ? atm

V = 40 L

n = no of mol of gas = w/Mwt

                       = 2500/32

                       = 78.125 mol

R = 0.0821 l.atm.k-1.mol-1

T = 22 c = 295.15 k

P = nRT/V

   = 78.125*0.0821*295.15/40

   = 47.3 atm

6) no of mol of CuO = w/mwt

                    = 40/79.5

                    = 0.503 mol

1 mol CuO = 1 mol H2o

no of mol of water formed = 0.503 mol

volume of water formed = nRT/P

n = 0.503 mol

R = 0.0821 l.atm.k-1.mol-1

T = 273.15 k

P = 1 atm

v = 0.503*0.0821*273.15/1

= 11.28 L