Energy & Reactions
What type of energy is stored in chemical bonds?
Bond energy or Potential energy
How do you calculate the heat needed to change a substance’s temperature?
q=mcΔT
What causes the volume to change in gases?
Pressure, Temperature, Shape of container
What happens to the pressure of a gas when you decrease the volume of its container while keeping the temperature the same?
The pressure increases because the gas particles collide more frequently with the container walls.
Which factor speeds up a chemical reaction?
What would happen to an object's potential energy as it begins moving?
Potential energy would decrease and Kinetic energy would increase
What happens to the energy of water molecules when ice melts at 0°C?
The molecules absorb energy and move more freely, changing from a solid to a liquid.
Why are gases easier to compress than solids and liquids?
Gas particles are far apart, leaving empty space
Why can gases expand to fill any container they are in?
Because gas particles move freely and spread out to occupy all available space.
Which factor slows down a chemical reaction?
What type of reaction absorbs heat from the surroundings?
Endothermic
When a substance absorbs heat from its surroundings, what type of energy change is occurring?
Endothermic – the substance is gaining energy from its surroundings.
Why does a basketball left outside overnight deflate?
Temperature drops, reducing gas pressure inside
How does increasing temperature affect gas pressure in a closed container?
Pressure increases
How does decreasing particle size affect a reaction rate?
Reaction speeds up because surface area increases
What causes an ice cube to melt when removed from a freezer?
Heat transfer from surroundings
What happens to temperature if the same amount of heat is applied to a substance with a higher specific heat?
Temperature increases less
When is the small size of gas particles important?
When the size of the container is also small
How does decreasing volume affect gas pressure if temperature is constant?
Pressure increases
What principle predicts how equilibrium shifts when reaction conditions change?
Le Chatelier’s Principle
What is the difference between specific heat capacity and heat capacity?
Specific heat is per unit mass; heat capacity is total heat needed
When a gas is compressed in a closed container, what happens to its temperature if no heat is lost to the surroundings?
The temperature increases because compressing the gas increases its internal energy.
If the pressure on a gas increases while the temperature stays the same, what happens to the volume of the gas?
The volume decreases because gas particles are compressed into a smaller space.
What law relates pressure, volume, and temperature of a gas?
Combined Gas Law (P1V1/T1=P2V2/T2)
What happens to a chemical reaction at equilibrium if you increase the concentration of a reactant?
The equilibrium shifts to produce more products. Or it shifts to the right.