Question

pressure and temperature have a select one relationship.
pressure and volume have a select one relationship.
pressure and particles have a select one relationship.
select one
inverse
direct

Explanation:

• Pressure and Temperature: According to Gay - Lussac's Law ($P = kT$, where $k$ is a constant when volume and amount of gas are fixed), when the temperature ($T$) of a gas increases, the pressure ($P$) increases and vice - versa. So, they have a direct relationship.
• Pressure and Volume: According to Boyle's Law ($PV=k$, where $k$ is a constant when temperature and amount of gas are fixed), when the volume ($V$) of a gas increases, the pressure ($P$) decreases and vice - versa. So, they have an inverse relationship.
• Pressure and Particles (amount of gas): According to the ideal gas law ($PV = nRT$, when $V$ and $T$ are fixed, $P=k'n$, where $k'=\frac{RT}{V}$ is a constant), when the number of moles ($n$, related to the number of particles) of a gas increases, the pressure ($P$) increases and vice - versa. So, they have a direct relationship.

Answer:

1. Pressure and Temperature: direct
2. Pressure and Volume: inverse
3. Pressure and Particles: direct