Evidence Of Chemical Change

Question 1

Recall that physical change is altering a substance without changing its _____

Answer 1

Composition

Question 2

Changes in state, phase, size, and shape are examples of _____ changes

Answer 2

Physical

Question 3

A chemical change is the result of a chemical reaction where new _____ are formed

Answer 3

Substances

Question 4

All chemical reactions have the general form:

Answer 4

Reactants —> Products

Question 5

The reactants are _____ to form the products

Answer 5

Rearranged

Question 6

Five evidences of chemical change:

Answer 6

1. Colour change
2. Formation of a gas (bubbles may appear)
3. Formation of a precipitate
4. Energy change (endothermic and exothermic)
5. Change in odour

Question 7

A chemical reaction that releases energy is _____

Answer 7

Exothermic

Question 8

A chemical reaction that absorbs energy is _____

Answer 8

Endothermic

Question 9

The law of conservation of mass states that the total number of atoms in the _____ is equal to the total number of atoms in the _____

Answer 9

Reactants

Products

Question 10

With the law of conservation of mass atom or ion bonds may be broken and new bonds may be formed but _____

Answer 10

there is no loss of any atoms or ions