Question

name eniza roya stemscopedia: energy in chemical reactions reading guide beginning on page 133 of your stemscopedia, answer the following questions. 1. what has to be done to make something cold? 2. give two examples listed in the reading of releasing thermal energy into the surroundings. a. b. 3. give an example from the reading of when energy is absorbed. 4. what is thermal energy? 5. what is exothermic? 6. what is endothermic? 7. what do all chemical reactions involve? 8. when does this change occur?

Explanation:

1. Heat must be removed to make something cold as heat is a form of energy and its removal lowers the temperature.
2. Examples of exothermic reactions (releasing thermal energy) could be combustion of wood (burning wood releases heat) and rusting of iron (a slow - exothermic process).
3. An example of energy absorption could be melting of ice (ice absorbs energy to change from solid to liquid).
4. Thermal energy is the energy that comes from the movement of atoms and molecules within a substance. The faster they move, the more thermal energy the substance has.
5. Exothermic refers to a chemical reaction or process that releases energy in the form of heat (and sometimes light) to the surroundings.
6. Endothermic refers to a chemical reaction or process that absorbs energy from the surroundings, usually in the form of heat.
7. All chemical reactions involve a change in energy. This is because chemical bonds are broken and formed during reactions, and these processes require or release energy.
8. This energy - change occurs when chemical bonds are broken and new bonds are formed during a chemical reaction.

Answer:

1. Remove heat.
2. a. Combustion of wood

b. Rusting of iron

1. Melting of ice
2. Energy from the movement of atoms and molecules within a substance.
3. A chemical reaction or process that releases energy (usually heat) to the surroundings.
4. A chemical reaction or process that absorbs energy (usually heat) from the surroundings.
5. A change in energy.
6. When chemical bonds are broken and new bonds are formed.