NY Regents Chemistry Exam June 2023, Questions 53-54

A sample of a gas in a sealed, rigid cylinder with a movable piston has a volume of 0.250 liter at STP.

53 Show a numerical setup for calculating the volume of this sample of gas at 298 K and 1.00 atm.

Solution: Let's look at Table T to choose the right equation for our problem. We are asked to calculate volume and we are given pressure and temperature. We will use combined gas to solve this.

STP stands for standard temperature and pressure which can be found in Table A on the Reference Table.

P1= 1atm P2 = 1.00atm

V1= 0.250 V2=?

T1= 273K T2 = 298K

(1atm)(0.250)/273K = (1.00atm)(V2)/ 298K

We are asked to show the setup and do not have to actually calculate the answer.

54 State a change in pressure that will cause the gas in the cylinder to behave more like an ideal gas.

Solution: Real gas is most like ideal gas at low pressure. We can lower the pressure for the gas in cylinder to behave most like an ideal gas.

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