Question

Difficulty: MediumDirect and Inverse Proportionality

A group of students conducted an experiment to study the relationship between the pressure and volume of a gas sample at a constant temperature. The gas was contained in a cylinder equipped with a movable piston. By adjusting the piston, the students varied the volume of the gas (VV, in liters) and measured the resulting pressure (PP, in atmospheres). The results are recorded in the table below.

TrialVolume (VV, L\text{L})Pressure (PP, atm\text{atm})
11.51.58.08.0
23.03.04.04.0
36.06.02.02.0
412.012.01.01.0

If the students perform a fifth trial and adjust the piston to a volume of 4.0 L4.0\text{ L}, which of the following is the most likely pressure of the gas sample?

  1. A
    1.3 atm1.3\text{ atm}
  2. 3.0 atm3.0\text{ atm}Answer
  3. C
    5.3 atm5.3\text{ atm}
  4. D
    48.0 atm48.0\text{ atm}

Answer

3.0 atm3.0\text{ atm}
The correct answer is the option stating 3.0 atm3.0\text{ atm}. The data in the table shows that pressure (PP) and volume (VV) are inversely proportional because their product is constant across all trials: P×V=1.5×8.0=3.0×4.0=6.0×2.0=12.0 LatmP \times V = 1.5 \times 8.0 = 3.0 \times 4.0 = 6.0 \times 2.0 = 12.0\text{ L}\cdot\text{atm}. For a volume of 4.0 L4.0\text{ L}, the pressure is calculated as P=12.04.0=3.0 atmP = \frac{12.0}{4.0} = 3.0\text{ atm}.

Step-by-Step Solution

1
Analyze the relationship between volume (VV) and pressure (PP) in the table.
As the volume increases from 1.51.5 to 12.0 L12.0\text{ L}, the pressure decreases from 8.08.0 to 1.0 atm1.0\text{ atm}. The product of pressure and volume remains constant for all trials: P×V=12.0 LatmP \times V = 12.0\text{ L}\cdot\text{atm}. This indicates that pressure and volume are inversely proportional.
To identify whether the variables have a direct or inverse relationship and determine the constant of proportionality.
2
Apply the inverse proportionality equation to find the pressure for the new volume of 4.0 L4.0\text{ L}.
P=12.0 Latm4.0 L=3.0 atmP = \frac{12.0\text{ L}\cdot\text{atm}}{4.0\text{ L}} = 3.0\text{ atm}.
To calculate the expected pressure when the volume is set to 4.0 L4.0\text{ L} using the determined relationship.

Key Concept

Inverse proportionality dictates that as one variable increases, the other decreases such that their product remains constant (y1xy \propto \frac{1}{x}, or x×y=kx \times y = k).
Estimated Time:1m 30s
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