Endothermic & Exothermic

Question 1

What needs to happen for a chemical reaction to occur?

Answer 1

Break the bonds between reactant atoms, and then form new bonds between product atoms.

Question 2

What are exothermic reactions?

Answer 2

Exothermic reactions are external and release heat.

It is a type of combustion reaction so

Examples include burning candle or sugar, rusting iron, oxidation, respiration, combustion, and neutralization.

Question 3

What are endothermic reactions?

Answer 3

Endothermic reactions are internal and absorb heat.

Examples include photosynthesis, melting of an ice cube, evaporating a liquid, and thermal decomposition.

Question 4

What is thermal decomposition?

Answer 4

To break down with heat.

Question 5

What is the chemical equation of photosynthesis?

Answer 5

Carbon dioxide + water + sunlight (energy) -> glucose + oxygen.

Question 6

What is the chemical equation of respiration?

Answer 6

Glucose + oxygen produces carbon dioxide + water + energy.

Question 7

What is enthalpy?

Answer 7

Heat content of a system; the energy required for a substance (reactants) to undergo a change. Represented by the symbol ΔH.

Question 8

What is the enthalpy equation?

Answer 8

ΔH = ΔHf (product) - ΔHi (reactant).

Question 9

What do exothermic reactions produce?

Answer 9

Exothermic reactions always produce and release energy, which means it feels hot.

Question 10

What is the temperature change in exothermic reactions?

Answer 10

Exothermic reactions increase temperature and always have a negative enthalpy.

Question 11

What do endothermic reactions do?

Answer 11

Endothermic reactions always absorb energy, which means they feel cold.

Question 12

What is the temperature change in endothermic reactions?

Answer 12

The temperature always decreases, and enthalpy is always positive.

Question 13

What is activation energy?

Answer 13

The energy required to break reactant bonds (Ea).

Question 14

What happens when the activation energy is smaller?

Answer 14

The less energy is needed for the reaction.

Question 15

What happens during a chemical reaction regarding energy?

Answer 15

All reactions initially absorb energy to break the bonds but release different amounts of energy.

Question 16

What is the collision theory?

Answer 16

Correct orientation, sufficient energy, particles must collide.

Question 17

What is transferred during a chemical reaction?

Answer 17

Energy.

Question 18

How is energy transferred in chemical reactions?

Answer 18

Through the breaking of chemical bonds in the reactants and creating new bonds in the products.

Question 19

What name is given to reactions that transfer energy to the surroundings?

Answer 19

Exothermic.

Question 20

What is the name given to reactions that transfer energy from surroundings to the reactants?

Answer 20

Endothermic.

Question 21

Examples of exothermic reactions?

Answer 21

Respiration, oxidation, combustion, neutralization.

Question 22

Examples of endothermic reactions?

Answer 22

Photosynthesis, sodium hydrogen carbonate and citric acid, thermal combustion.

Question 23

What happens to the energy of products if a reaction gives out energy?

Answer 23

The energy of the products will be less.

Question 24

Why do not all collisions between particles result in a chemical reaction?

Answer 24

Because not all of the collisions have enough energy to react.

Question 25

What investigation would you do to find out if a reaction is endothermic or exothermic?

Answer 25

Record the initial temperature of reactants and then the final temperature to find the temperature difference.

Question 26

Proof that an exothermic reaction has taken place?

Answer 26

Through an increase in temperature from the reactants to the products.

Question 27

Why does candy feel slightly cooled in the mouth?

Answer 27

During this reaction, heat is being removed from the surroundings.

Question 28

What are reactants in a chemical reaction?

Answer 28

Chemicals you start off with, before the reaction takes place.

Question 29

What are products in a chemical reaction?

Answer 29

Chemicals produced as a result of the reaction.

Question 30

Is boiling water into steam endothermic or exothermic?

Answer 30

Endothermic.

Question 31

Is burning wood in a fireplace endothermic or exothermic?

Answer 31

Exothermic.

Question 32

Is melting ice into liquid water an endothermic or exothermic process?

Answer 32

Endothermic.

Question 33

Is the combustion of propane in a gas grill endothermic or exothermic?

Answer 33

Exothermic.

Question 34

Is photosynthesis endothermic or exothermic?

Answer 34

Endothermic.

Question 35

Is a cold pack getting colder when activated endothermic or exothermic?

Answer 35

Endothermic.

Question 36

Is a hand warmer releasing heat when shaken endothermic or exothermic?

Answer 36

Exothermic.

Question 37

Does condensation of steam into water absorb or release heat?

Answer 37

Release heat.

Question 38

Is freezing water into ice cubes in a freezer endothermic or exothermic?

Answer 38

Exothermic.

Question 39

Is cooking pasta in boiling water endothermic or exothermic?

Answer 39

Endothermic.

Question 40

Is the rusting of iron endothermic or exothermic?

Answer 40

Exothermic.

Question 41

What type of reaction is a burning candle?

Answer 41

Exothermic.

Question 42

Is respiration in cells endothermic or exothermic?

Answer 42

Exothermic.

Question 43

What happens during the decomposition of calcium carbonate when heated exto or endo

Answer 43

It is an endothermic reaction.

Question 44

Is cooking an egg endothermic or exothermic?

Answer 44

Endothermic.

Question 45

What happens during fireworks explosions? endo or exto

Answer 45

They release sound, heat, and light energy. exothermic