Physical and Chemical Reactions

Question 1

Cooking an egg? Chemical reaction or Physical change? (C or P)

Answer 1

C

Question 2

Water freezing

Answer 2

P

Question 3

Chopping wood

Answer 3

P

Question 4

Milk turning sour

Answer 4

C

Question 5

Mixing sand and water

Answer 5

P

Question 6

What is some evidence that a chemical reaction has occurred?

Answer 6

Change in color
Change in odor
Change in temperature
Change in “substance”
Produces light
Produces a gas
Produces a solid
The change is difficult or impossible to reverse

Question 7

What is an exothermic reaction?

Answer 7

A reaction that gives off heat, making surroundings hotter. Hand warmers.

Question 8

What is an endothermic reaction?

Answer 8

A reaction that takes in heat, making the surroundings colder. Ice pack

Question 9

Balance the following equation. _CO2+_H2O=_C6H12O6+_O2

Answer 9

6;6;1;6

Question 10

Define “conservation of matter”.

Answer 10

Matter cannot be created or destroyed, it can only change form.

Question 11

True or False. Chemical reactions always rearrange atoms to make one or more new substances.

Answer 11

True.