Particle Model & Pressure Flashcards
All 8 cards in this deck
What causes the pressure of a gas on the walls of its container?
The gas particles collide with the walls; each collision exerts a force, and pressure is the force per unit area.
What are the steps to explain why heating a fixed mass of gas at constant volume increases its pressure?
e.g. a sealed aerosol can taken from a cold room into a warm room
- Particles gain kinetic energy, so their mean speed increases.
- They hit the walls more often and with a greater force each time.
- Greater total force on the same area, so the pressure inside the can increases.
True or false? When a sealed can of gas is taken from a cold room to a warm room at constant volume, the mean distance between the particles increases.
False. The mean distance between the particles does not change, because the volume and the number of particles stay the same.
What is meant by absolute zero?
−273 °C (0 K), the lowest possible temperature, at which the particles have no movement (minimum kinetic energy).
What is the equation linking a temperature in kelvin and the same temperature in degrees Celsius?
temperature (K) = temperature (°C) + 273, so subtract 273 to convert from kelvin to degrees Celsius.
True or false? A temperature on the kelvin scale can be negative.
False. 0 K is absolute zero, the lowest possible temperature, so kelvin temperatures are never negative.
True or false? A temperature change of 1 °C is the same size as a temperature change of 1 K.
True. Both scales have the same size of degree; the kelvin scale just starts 273 degrees lower, at absolute zero.
At the same temperature, why does putting more gas particles into the same volume increase the pressure?
The particles hit the container walls more often, so the total force on the walls, and so the pressure, increases.