gr 10-chemistry (unit 2.3)

Question 1

What happens to bonds in a chemical reaction?

Answer 1

During a chemical reaction bonds in the reactants are broken and new bonds are made in the products

Question 2

What happens to the reactants in a chemical change for it to occur?

Answer 2

The reactants must collide with enough energy to break the bonds in the reactants

Question 3

What is activation energy?

Answer 3

The minimum amount of energy needed for the reaction to occur

Question 4

True or false: chemical reaction require an in total input of energy- most reactants will not react by simply mixing them together

Answer 4

True

Question 5

What is “the system”?

Answer 5

The system is the materials involved in the chemical reaction and evreything else in the universe is the surroundings

Question 6

What does the law of conservation state in terms of energy in the universe?

Answer 6

It states the total energy of the universe is constant- energy cannot be created or destroyed

Question 7

Endothermic reactions

Answer 7

• Absorbs energy
• starts with less and ends with more
• surrounding temp decreases (gets colder)

Question 8

Exothermic reactions

Answer 8

• Releases energy
• starts with more and ends with less
• surrounding temp increases (gets hotter)

Question 9

What are energy-level diagrams?

Answer 9

• They are diagrams that show the relative energy levels of the reactants and products in a reaction
• shows how energy changes in a reaction

Question 10

Is there more or less energy required to break bonds in endothermic reactions?

Answer 10

There is more energy required to break bonds than energy that is released when new bonds form

Question 11

True or false: there is an overall release of energy, and the products are at a lower energy than the reactants in exothermic reactions

Answer 11

True

Question 12

is photosynthesis endothermic or exothermic and why

Answer 12

it’s endothermic becuase it absorbs energy from the sunlight and stores it to make sugar