topic 14 - particle model

• How do gas particles move in a container?

  They move in random directions.
• What happens when gas particles collide with container walls?

  They exert a force at right angles.
• What is the equation for pressure?

  Pressure (Pa) = Force (N) / Area (m²)
• What is the formula for pressure in symbols?

  P = F / A
• How are particles in a gas structured?

  They have almost no forces between them.
• What effect does increasing temperature have on gas pressure?

  Gas pressure increases as temperature increases.
• What can be said about the rate of collisions in gas A and gas B?

  Gas A has more collisions than gas B.
• Why does pressure increase with temperature at constant volume?

  Kinetic energy of molecules increases.
• What happens to the rate of collisions as temperature increases?

  Collisions become more frequent.
• What is affected by the average kinetic energy of gas molecules?

  The temperature of the gas.
• What is the relationship between pressure and volume for a fixed mass of gas at constant temperature?

  Pressure and volume product is constant.
• How does gas pressure exert force on container walls?

  Net force acts at right angles to surfaces.
• What happens to pressure when the volume of a gas increases?

  Pressure decreases as volume increases.
• What is the unit of pressure?

  Pascal (Pa).
• How do you convert Celsius to Kelvin?

  Add 273 to Celsius.
• What is the equation for pressure and volume with fixed mass and constant temperature?

  P₁ × V₁ = P₂ × V₂
• What is absolute zero in Celsius?

  −273 °C
• What happens to the internal energy of a gas when work is done on it?

  Internal energy of the gas increases.
• Why does the temperature of air in a bike pump increase when pumped?

  Work done increases internal energy.
• What is the definition of density?

  Mass per unit volume of a material.
• What is the equation for density?

  ⍴ = m / v
• What are the units for density?

  kg/m³
• What is a state of matter?

  A form based on particle arrangement.
• What are the states of matter in order of density?

  Gas, Liquid, Solid.
• How does kinetic theory explain the structure of liquids?

  Particles move randomly at slow speeds.
• How do particles in a solid move?

  They vibrate around a fixed position.
• What is conserved during a change of state?

  Mass
• How does a change of state differ from a chemical change?

  Material can return to previous properties.
• What is the internal energy of a substance?

  Energy stored by the particles.
• What can heating a substance do?

  Raise temperature or change state.
• What is sublimation?

  Solid turns directly into a gas.
• What is the difference between physical and chemical changes?

  Physical changes can be reversed.
• What factors determine temperature change of a system?

  Mass, material type, energy input.
• How does heating cause a substance to change state?

  Particles gain potential energy to break bonds.
• Why does heating increase the temperature of a substance?

  It increases thermal energy and kinetic energy.
• What is the equation for energy change when heated?

  ΔE = m c Δ��
• What are the units for energy change?

  Joules (J), kilograms (kg), °C.
• What is specific latent heat?

  Energy needed to change state without temperature change.
• What is the equation for energy required to change state?

  E = mL
• What are the units for energy required to change state?

  Joules (J), kilograms (kg).