Agas occupies 525ml at a pressure of 85.0kpa. what would the volume of the gas be at a pressure of 65.0kpa

Boyle's law gives the relationship between pressure and volume of gas.
It states that at a constant temperature, the pressure of gas is inversely proportional to volume of gas for a fixed amount of gas.
PV = k
where P - pressure, V- volume and k - constant 
substituting these values into the equation;
85.0 kPa x 525 mL = 65.0 kPa x V
V = 687 mL 

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