Unit 6

Question 1

List the 7 signs that a chemical reaction has taken place.

Answer 1

1. Temperature change
2. Gas evolved (given off)
3. Dramatic Color Change
4. Formation of a precipitate
5. New odor
6. Light/sparks
7. Sound

Question 2

What does the symbol (l) mean?

Answer 2

liquid

Question 3

What does the symbol (aq) mean?

Answer 3

aqueous; substance has been dissolved in water

Question 4

What does the symbol (ppt) mean?

Answer 4

precipitate

Question 5

What does the symbol (g) mean?

Answer 5

gas

Question 6

What does the symbol (s) mean?

Answer 6

solid

Question 7

What does the symbol → mean?

Answer 7

yields/produces

Question 8

What does the symbol —△→ mean?

Answer 8

reaction requires heat

Question 9

What does the symbol —Pt→ mean?

Answer 9

reaction requires a catalyst, in this case platinum

Question 10

What does the symbol —ele→ mean?

Answer 10

reaction requires electricity

Question 11

What kind of reaction is this?:

A + B → AB

Answer 11

Synthesis

Question 12

What kind of reaction is this?:

AB → A + B

Answer 12

Decomposition

Question 13

What kind of reaction is this?:

A + BC → AC + B

Answer 13

Single Replacement

Question 14

What kind of reaction is this?:

AB + CD → AD + CB

Answer 14

Double Replacement

Question 15

What kind of reaction is this?:

CH₄ + O₂ —△→ CO₂ + H₂O

Answer 15

Combustion

Question 16

What kind of reaction is this?:

HX(acid) + Z(OH)(base) → a salt + H₂O

Answer 16

Neutralization

Question 17

What kind of element cannot occur alone? It occurs as a pair. There are 7.

Answer 17

Diatomic Element

H₂, N₂, O₂, F₂, Cl₂, Br₂, I₂

Question 18

What does a decomposition of a metal carbonate produce?

ex. Li₂(CO₃) —△→

Answer 18

It produces a metal oxide and CO₂.

Li₂O +CO₂

Question 19

What does a decomposition of a metal hydroxide produce?

ex. Ca(OH)₂ —△→

Answer 19

It produces a metal oxide and water—except Group 1.

CaO + H₂O

Question 20

What does a decomposition of a metal chlorate produce?

ex. 2Li(ClO₃) —△→

Answer 20

It produces a metal chloride and oxygen gas.

2LiCl + 3O₂

Question 21

What shows just the species that are NOT aqueous ions as products. This is the precipitate.

Answer 21

The net ionic equation.

Question 22

What are the aqueous ions called? Those ions that do not come together to form a precipitate. (must look at solubility rules for this)

Answer 22

The spectator ions.

Question 23

What must a combustion reaction always have?

Answer 23

O₂ —△→ CO₂ + H₂O

Question 24

What must a neutralization reaction always have?

Answer 24

an acid + a base → a salt + water

Question 25

In what instance do you have a precipitate for a product?

Answer 25

You have a precipitate in the product when you have a double replacement reaction with two aqueous substances.

Question 26

In part 1a. of the lab, what was added to the copper II sulfate? What was the resulting color of the metal?

Answer 26

Zinc was added to the copper II sulfate. It went from silver to reddish brown.

Question 27

In part 1b. of the lab, what was added to the aqueous silver nitrate? What was the resulting color of the metal?

Answer 27

Copper was added to the silver nitrate. It went from reddish brown to silver.

Question 28

In part 2a. of the lab, what were the beginning and ending colors of the ammonium dichromate after it was heated?

Answer 28

The ammonium dichromate went from bright orange to dark forest green.

Question 29

In part 2b. of the lab, what happened to the C₁₂H₂₂O₁₁ (sugar) when it was heated?

Answer 29

The sugar turned from white to black and brown. It also had some smoke and a new odor.

Question 30

In part 3a. of the lab, what happened when sodium hydroxide was added to ferric chloride?

Answer 30

The ferric chloride went from orange to dark brown.

Question 31

In part 3b. of the lab, what happened when ammonium hydroxide was added to copper II sulfate?

Answer 31

The copper II sulfate went from light blue to a very dark blue.

Question 32

In part 3c. of the lab, what happened when potassium iodide was added to lead II nitrate?

Answer 32

The lead II nitrate went from cloudy-clear to a bright solid-colored yellow.