Question

In the combustion chamber of an engine, the initial volume is 450 cm3 at a pressure of 1.0 atmosphere. If the piston displaces 402 cm3 of the total, what is the resulting pressure in the combustion chamber? (Assume negligible temperature change.) Hint: Calculate the new volume by subtracting the amount of space the piston takes up from the initial volume

Answer 1

9.0 atm is the answer 

Answer 2

Answer:

9.375 atm  

Explanation:

Initial volume = 450 cm³

Volume displaced by the piston = 402 cm³

Final volume = Initial volume – displaced volume = 450 cm³ – 402 cm³ = 48 cm³

Initial pressure = 1.0 atm

According to Boyle’s Law,  

P₁V₁ = P₂V₂  

where P₁, P₂ are the initial and final pressure respectively, V₁ and V₂ are the initial and final volume respectively.  

Substituting the given data we have,  

450 cm³ x 1 atm = 48 cm³ x P₂  

P₂ = (450 cm³ x 1 atm) / 48 cm³ = 9.375 atm