3. A gas initially at 4.0 L, 1.2 atm, and 66°C undergoes a change so that its final volume and temperature are 1.7 L and 42°C. What is its final pressure? Assume the number of moles remains unchanged.
We are given the initial pressure, the initial volume, the initial temperature, the final volume, and the final temperature; we are asked to solve for the final pressure of the gas. Since we assume that the amount of gas is constant, we use combined gas law.
Combined gas law is given by
where:
P₁ = initial pressure
V₁ = initial volume
T₁ = initial temperature (in kelvin)
P₂ = final pressure
V₂ = final volume
T₂ = final temperature (in kelvin)
Note: If the given temperature is in °C, we must convert it to kelvin (K) first before substituting in the formula.
Listing the given values, we have
Arranging the equation, we can now solve for the final pressure. Therefore,
Answers & Comments
✏️COMBINED GAS LAW
We are given the initial pressure, the initial volume, the initial temperature, the final volume, and the final temperature; we are asked to solve for the final pressure of the gas. Since we assume that the amount of gas is constant, we use combined gas law.
Combined gas law is given by
where:
P₁ = initial pressure
V₁ = initial volume
T₁ = initial temperature (in kelvin)
P₂ = final pressure
V₂ = final volume
T₂ = final temperature (in kelvin)
Note: If the given temperature is in °C, we must convert it to kelvin (K) first before substituting in the formula.
Listing the given values, we have
Arranging the equation, we can now solve for the final pressure. Therefore,