Chemistry Test Review

Vocab

1

Group 1 of the periodic table, super reactive with ONE valence electron

Alkali Metals

2

The part that gets dissolved in the solution. (Generally solid)

Solute

3

This group of elements makes up the middle chunk of the periodic table. Includes elements such as Iron, Gold, and platnium.

Transition Metals

4

In a chemical equation what is the right side of the equation referred to as?

Products

5

What does a covalent bond form between?

2 nonmetals

Lewis Dot Structures and First 20 Elements

1

Draw the Lewis dot structure for Hydrogen.

Whiteboard should have an "H" with ONE valence electron on it!

2

Symbol: Na

What element am I?

Sodium

3

Draw the lewis dot structure for Neon.

Ne is the correct abbreviation. Ne needs EIGHT valence electrons around it, a perfectly full valence!

4

Symbol: K

What element am I?

Potassium 

5

Draw the lewis dot structure for Bromine (Br)

Br should have SEVEN valence electrons around it.

Balancing Chemical Equations

1

Balance the following equation. Use a table to track atoms.

H₂ + O₂ → H₂O

2H₂ + O₂ → 2H₂O

2

Balance this equation:

N₂ + H₂ → NH₃

N₂ + 3H₂ → 2NH₃

3

Balance this equation:

C₃H₈ + O₂ → CO₂ + H₂O

C₃H₈ + 5O₂ → 3CO₂ + 4H₂O

4

Balance this:

Fe₂O₃ + CO → Fe + CO₂

Fe₂O₃ + 3CO → 2Fe + 3CO₂

5

Balance this:

Al₂(SO₄)₃ + Ca(OH)₂ → Al(OH)₃ + CaSO₄

Al₂(SO₄)₃ + 3Ca(OH)₂ → 2Al(OH)₃ + 3CaSO₄

Covalent and Ionic Bonding

1

Mg + O -> MgO

Draw the bonding diagram.

(If Ionic use arrows for transfer and note ions + charges, If covalent circle shared pairs)

Mg has 2 valence electrons, O has 6 valence electrons.

Mg transfers 2 electrons to O

Ions form: [Mg]²⁺ [O]²⁻

2

CaCl₂

Draw the bonding diagram.

(If Ionic use arrows for transfer and note ions + charges, If covalent circle shared pairs)

Ca loses 2 electrons

Two Cl atoms each gain 1 electron

Ions: [Ca]²⁺ + [Cl]⁻ + [Cl]⁻

3

H₂O

Draw the bonding diagram.

(If Ionic use arrows for transfer and note ions + charges, If covalent circle shared pairs)

Oxygen in center, 2 Hs (one on each side of O)

Two shared pairs (O–H)

Two lone pairs on oxygen (4 electrons total on O and 2 bonds from O)

4

NH₃

Draw the bonding diagram.

(If Ionic use arrows for transfer and note ions + charges, If covalent circle shared pairs)

Covalent

One N, three Hs

Three circled pairs between N and H. N has ONE lone PAIR of electrons.

5

Al₂O₃

Draw the bonding diagram.

(If Ionic use arrows for transfer and note ions + charges, If covalent circle shared pairs)

Each Al loses 3 electrons

Each O gains 2 electrons 

To balance electrons:

• 2 Al atoms lose 6 electrons total

• 3 O atoms gain 6 electrons total

Ions: [Al]³⁺ [Al]³⁺ [O]²⁻ [O]²⁻ [O]²⁻

Chemical Reactions

1

Think back to borax crystal lab...one of the 5 signs of a chemical reaction was present when we checked them after 48 hours. What was it?

Formation of a precipitate (our crystal)

2

During the lab where we lit different metals on fire, which of the 5 signs of a chemical reaction was evidences by the flame?

Color change

3

A ___________ solution contains the MAXIMUM amount of solute that dissolves in a solvent.

Saturated

4

We combined 30% hydrogen peroxide with Potassium Iodide in an erlenmeyer flask. Was the reaction exothermic or endothermic? What was the evidence of a chemical reaction?

Exothermic (heat was lost to the environment)

Evidence: Temp change, as it increased. We also saw color change.

5

Combine aspirin and vinegar. What is the evidence of a chemical reaction?

Bubbling! It's also technically endothermic so there is also a temp decrease