Unit 2: Chemical Reactions

Question 1

Catalyst

Answer 1

A substance that speeds up the rate of a reaction without causing permanent change.

Question 2

Enzyme

Answer 2

A molecule found within a biological system that increases the speed of a chemical reaction.

Question 3

Combustion Reaction

Answer 3

The reaction of a substance with oxygen, producing one or more oxides, heat, and light.

Question 4

What 3 things from the “Fire Triangle” are nessesary for a combustion reaction?

Answer 4

1) Fuel (hydrocarbon)
2) Oxygen to burn it with
3) Something to ignite the reaction (Spark)

Question 5

What is the general word equation for combustion?

Answer 5

Hydrocarbon + Oxygen→ Carbon Dioxide + Water

*CARBON DIOXIDE AND WATER ARE ALWAYS THE PRODUCTS OF COMBUSTION*

Question 6

Incomplete Combustion

Answer 6

Something that occurs when there is not enough oxygen present in the reaction.

Question 7

What are the pros and cons of incomplete combustion?

Answer 7

Good: Bright yellow flames used in candles

Bad: Porduces elemental carbon (soot) and toxic carbon monoxide (CO)

Question 8

What are 3 dangers of carbon monoxide?

Answer 8

1) A toxic gas with no colour or smell
2) Binds to oxygen binding sites in the blood, the longer its breathed in the fewer binding sites are availible to carry the blood
3) Symptoms include headache to suffocation

Question 9

Solubility

Answer 9

A measure of the extent to which a solute dissolves in a solvent at a given temperature and pressure.

Question 10

What is the “Solubility Table” used for? How do you use it?

Answer 10

We use the table to predict the solubilty in water of an ionic compound in a double displacement reaction.

To use: Look for the second element (non-metal) on the chart and find it’s compounded element. The chart will say whether it is soluable or has low solubility (Solid).

Question 11

What are the 5 steps to solving a solubility problem?

Answer 11

Step 1: Identify the type of reaction and its products

Step 2) Look up solubility of the products

Step 3) Indicate states of reactants and products

Step 4) Write the chemical equation

Step 5) Balance the equation

*LOW SOLUBILITY MEANS SOLID*

Question 12

What happens if there is no precipitate formed in a solubility reaction?

Answer 12

There was no reaction.

Question 13

Total Ionic Equation

Answer 13

A chemical equation that illustrates all soluable (aq) ionic compounds in their ionic form.

Question 14

Spectator Ions

Answer 14

Ions present in the products and reactants of the equation. They cancel eachother and when rewritten it is called a net ionic equation.

Question 15

Net Ionic Equation

Answer 15

An equation that only show the ions that were involved in the chemical reaction.

A re-writtten equation without spectator ions.

Question 16

What are the 3 clues that tell us a reaction is proceeding?

Answer 16

1) A precipitiate is formed
2) A gas is produced
3) The solution becomes neutral

Question 17

How does a double displacement reaction sometimes occur in 2 steps?

Answer 17

When a double displacement reaction produces 2 products one of them spontaneously demcomposes to produce a gas.

Question 18

Neutralization

Answer 18

The process of making a neutral solution by combining an acid (H) with a base (OH). A water and a salt will result.

Question 19

What are 2 ways neutralization is used in everyday life?

Answer 19

1) They’re used to treat acid or base spills
2) Milk of Magnesia: a medicine that neutralizes stomach acid

Question 20

What is the “Activity Series”?

Answer 20

A ranking of metal elements according to reactivity.

It increases going from bottom to top.

Question 21

How does the activity series work?

Answer 21

In a single displacement reaction one element can displace element below it but not above it on the activity series. The farther appart two elements are, the more likely the displacement will occur. The less reactive element appears as a solid.

Example: Ni is above Ag therefore they would switch in a reaction.