Question

which of the following relationships are direct?
□ pressure-temperature
□ volume-temperature
□ pressure-volume
□ volume-amount

Explanation:

To determine direct relationships, we use gas laws:

• Pressure - Temperature: By Gay - Lussac's law ($\frac{P_1}{T_1}=\frac{P_2}{T_2}$ at constant volume), pressure and temperature are directly proportional.
• Volume - Temperature: By Charles's law ($\frac{V_1}{T_1}=\frac{V_2}{T_2}$ at constant pressure), volume and temperature are directly proportional.
• Pressure - Volume: By Boyle's law ($P_1V_1 = P_2V_2$ at constant temperature), pressure and volume are inversely proportional.
• Volume - Amount: By Avogadro's law ($\frac{V_1}{n_1}=\frac{V_2}{n_2}$ at constant T and P), volume and amount (moles, n) are directly proportional.

Answer:

• pressure - temperature
• volume - temperature
• volume - amount