Question

Dry ice (solid CO2) has occasionally been used as an "explosive" in mining. A hole is drilled, dry ice and a small amount of gunpowder are placed in the hole, a fuse is added, and the hole is plugged. When lit, the exploding gunpowder rapidly vaporizes the dry ice, building up an immense pressure. Assume that 391 g of dry ice is placed in a cavity with a volume of 0.770 L and the ignited gunpowder heats the CO2 to 695 ∘C. What is the final pressure inside the hole?

Answer 1

Answer:

Final pressure = 0.77atm

Explanation:

The concept used to approach this question is the Ideal gas equation

PV = nRT

where P = pressure

V = Volume

n = number of mole or amount of substance

R = ideal gas constant

T = Temperature in Kelvin

• from the parameters given ; mass = 391g

• volume = 0.770 L

• Temperature = 695 ∘C = 695 + 273 = 968K

• R = 0.0821

• number of moles = mass/molar mass

• molar mass of CO2 = 12 + 2x16 = 44g/mol

• number of moles = 391g/44g/mol = 8.886mol

plugging into the equation to get the final pressure,

• from PV = nRT

• P = nRT/V = 8.886 x 0.0821 x 968 / 0.770

• Final pressure = 0.77atm