Chapter 5

Question 1

physical change

Answer 1

appearance of substance changes but not its composition

Question 2

Chemical change

Answer 2

substances react to form new substances with new formulas and properties

Question 3

iron nail + oxygen =

Answer 3

rust

Question 4

fuel + air =

Answer 4

co2 and water

Question 5

what does a chemical change produce?

Answer 5

one or more new substances

Question 6

7 types of visible evidence of a chemical reaction

Answer 6

1. change in color
2. Formation of gas (bubbles)
3. Formation of a solid (precipitate)
4. Heat (or a flame) produced or heat absorbed
5. Production of line
6. Changes in odor
7. Changes in electrical or magnetic properties

Question 7

Chemical reactions

Answer 7

• old bonds are broken and new bonds are formed

- atoms in the reactants are rearranged to form one or more different substances

Question 8

Chemical equation

Answer 8

gives the chemical formulas of the reactants on the left of the arrow and the products on the right

Question 9

symbols used in chemical equations show

-3 things

Answer 9

1. the states of the reactants
2. the states of the products
3. the reaction conditions

Question 10

Conservation of mass

Answer 10

• atoms are not lost or gained

- the number of each atom in the reactants is equal to the number of each atom in the products

Question 11

in a balanced chemical equation what must there be?

Answer 11

the same number of each type of atom on the reactant side and on the product side

Question 12

Coefficients

Answer 12

• in balanced equations

- used in front of one or more formulas