8th Grade Structure & Properties of Matter

Front

What happens to water molecules when a large quantity of thermal energy is added to water in the liquid state?

Back

The molecules gain kinetic energy, move farther apart, and become a gas.

Front

What data would provide the best evidence for determining if a chemical reaction absorbed or released thermal energy?

Back

The temperature inside the beaker before and after the reaction.

Front

What is the best choice for making a heat pack in a science classroom using chemical reactions?

Back

Chemical reaction 4.

Front

What happens to the molecules in ice when thermal energy is added?

Back

The molecules in the ice speed up.

Front

What is the ideal temperature range for a chemical reaction used in cold packs for treating injuries?

Back

0°C to 4°C.

Front

What is thermal energy?

Back

Thermal energy is the energy that comes from the temperature of matter. It is the total kinetic energy of the particles in a substance.

Front

Define kinetic energy in the context of molecules.

Back

Kinetic energy is the energy that an object possesses due to its motion. In molecules, it refers to the energy they have due to their movement.

Front

What is the effect of adding thermal energy to a solid?

Back

Adding thermal energy to a solid causes its molecules to vibrate faster, potentially leading to a change in state.

Front

What is an endothermic reaction?

Back

An endothermic reaction is a chemical reaction that absorbs thermal energy from its surroundings.

Front

What is an exothermic reaction?

Back

An exothermic reaction is a chemical reaction that releases thermal energy to its surroundings.