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Question

A student collects 450. mL of HCl gas at a pressure of 101 kPa and a temperature of 17ºC. What would the volume of the gas be if the temperature was increased to 25ºC and the pressure was increased to 104 kPa?

Answer 1

For this problem we can use the combined gas law. The combined gas law is a combination of Boyle's, Charles's and Gay-Lussac's law. Mathematically we write this as:

 

(P₁V₁)/T₁= (P₂V₂)/T₂

 

You have values for two different conditions:

P₁ = 101kPa                                    P₂ =104 kPa

V₁ = 450 mL                                   V₂ =  ?                         

T₁ = 17ºC                                       T₂ = 25ºC

 

We need to convert temperature to Kelvin by adding 273.15

 

T₁ =(17 +273.15)K =290.15 K                  T₂= (25+273.15) K = 298.15 K

 

Now use the equation given above to solve for V₂.

 

Rearranging the equation in terms of V₂ we get:

 

V₂ = (P₁V₁T₂)/(T₁P₂) =(101 kPa × 450 mL ×298.15 K)/(290.15 K ×104 kPa) =449 mL