Question

A gas has a volume of 50.0 cm3 at a temperature of -73°C. What volume would the gas occupy at a temperature of -123°C if the pressure stays constant?

f 5.0 cm3

g 3.75 cm3

h 37.5 cm3

j 50.0 cm3

Answer 1

Answer:

h. 37.5 cm³

Explanation:

• We can use the general law of ideal gas: PV = nRT.

where, P is the pressure of the gas in atm.

V is the volume of the gas in L.

n  is the no. of moles of the gas in mol.

R is the general gas constant,

T is the temperature of the gas in K.

• If n and P are constant, and have different values of V and T:

(V₁T₂) = (V₂T₁).  

V₁ = 50.0 cm³, T₁ = -73°C + 273 = 200 K,

V₂ = ??? cm³, ​T₂ = -123°C + 273 = 150 K.

∴ V₂ = (V₁T₂)/(T₁) = (50.0 cm³)(150 K)/(200 K) = 37.5 cm³.

• So, the right choice is: h. 37.5 cm³.