Unit 3: Reactions

Question 1

types of changes in matter

Answer 1

chemical, physical, nuclear

Question 2

signs of chemical change

Answer 2

-change in colour
-gas produced
-energy created (heat sound light)
-formation of a precipitate
-difficult to reverse

Question 3

Law of conservation of mass

Answer 3

in a chemical change atoms are neither created nor destroyed

mass of the products = mass of the reactants

Question 4

Factors that impact the rate of reaction

Answer 4

(slower or faster)
-temperature
-pressure
-surface area
-concentration of the reactant
-stirring/mixing
-catalyist

Question 5

Collision reaction theory

Answer 5

Chemical reactions must:
-hit hard (collide with force)
-hit the right way (collide the correct orientation)

if not - NR

Question 6

Activation energy

Answer 6

measures how much kinetic energy is required for molecules in a reaction to collide hard enough for effective collisions
-below activation energy is NR

Question 7

catalyists

Answer 7

a substance that lowers the activation energy of a reaction, resulting in more product being made faster and at a normal temperature
ex. a spark or match for gasoline

Question 8

types of chemical reactions

Answer 8

-synthesis
-decomposition
-combustion (involves oxygen gas always and for complete combustion - produces oxides and h20 and co2
-single displacement (ACTIVITY SERIES)
-double displacement