Chemistry Short Answers UNIT TEST

Question 1

5

What is the Particle Theory of Matter?

Answer 1

1. All matter is made up of tiny particles.
2. Particles are always moving.
3. Particles are attracted to each other.
4. There are spaces between particles.
5. Particles move faster when heated.

Question 2

6

What are the States of Matter?

Answer 2

1. Melting
2. Evaporation
3. Condensation
4. Freezing
5. Sublimation
6. Deposition

Question 3

6

What are the Changes of State?

Answer 3

Solid → Liquid: Melting
Liquid → Gas: Evaporation
Gas → Liquid: Condensation
Liquid → Solid: Freezing
Solid → Gas: Sublimation
Gas → Solid: Deposition

Question 4

What is Physical Properties of Matter?

Answer 4

Characteristics observed without changing the substance (EX: Colour, State, Density).

Question 5

What is the Chemical Properties of Matter?

Answer 5

How a substance reacts with others (EX: Flammability, Reactivity with Acid).

Question 6

What is a Qualitative Property?

Answer 6

Descriptive without numbers (EX: Colour, Texture, Smell)

Question 7

What is a Quantitative Property?

Answer 7

Measured with numbers (EX: Mass, Volume, Density)

Question 8

*

What is the Formula for Density

Answer 8

Density= Mass / Volume

Question 9

Define and Identify Chemical Change

Answer 9

A new substance is formed (EX: burning wood)

Question 10

Define and Identify Physical Change

Answer 10

No new substance is formed (EX: melting ice)

Question 11

What are the 5 clues that a Chemical Change has occured?

Answer 11

1. Change in color
2. Gas is produced (bubbling)
3. Heat or light is emitted
4. A precipitate (solid) forms.
5. The change is difficult to reverse

Question 12

Explain the Chemical tests for Gases and how they are used to identify Unknown Gases

Answer 12

Hydrogen Test: A burning splint makes a “pop” sound.

Oxygen Test: A glowing splint reignites.

Carbon Dioxide Test: Turns limewater cloud

Question 13

What are the Names of the first 20 Elements on the Periodic Table

Answer 13

1. Hydrogen
2. Helium
3. Lithium
4. Berium
5. Boron
6. Carbon
7. Nitrogrn
8. Oxygen
9. Fuorine
10. Neon
11. Sodium
12. Magnesium
13. Aluminum
14. Silicon
15. Phosphrus
16. Sulfer
17. Chlorine
18. Argon
19. Potasium
20. Calcium

Question 14

4

What is Dalton’s Atomic Theory?

Answer 14

1. Matter is made of tiny indivisible particles (atoms)
2. Atoms of the same element are identical
3. Atoms combine in fixed ratios to form compounds.
4. Atoms are rearranged in chemical reactions

Question 15

2

What Criteria did Mendeleev use to arrange the Elemets in the Periodic Table?

Answer 15

1. Arranged by increasing atomic mass.
2. Elements with similar properties were grouped into columns

Question 16

*

What are the Properties of the different types of Elements

Metal, Non-Metals, and Metalloids

Answer 16

Metals: Conduct electricity, malleable, shiny.

Non-Metals: Poor conductors, brittle, dull.

Metalloids: Have properties of both metals and non-metals

Question 17

What is a Chemical Formula? How does a Chemical Formula indicate the Elements present and the numbers of each?

Counting Atoms

Answer 17

Show elements and their ratios (e.g., H₂O means 2 hydrogen atoms and 1 oxygen atom

Question 18

*

What are the Horizontal Rows of the Periodic Table Called?

Answer 18

Periods

Question 19

*

What are the Vertical Collums of the Periodic Table Called?

Answer 19

Groups/Families

Question 20

What is special about Elements in the same group?

Answer 20

They have the same number of valence electrons

Question 21

What are the Names and Properties of Elements of Different Groups or Families?

Answer 21

1. Alkali Metals (+1)
2. Alkaline Earth Metals (+2)
3. Halogens (-1)
4. Noble Gases (0)

Question 22

Study the development of the model of Atoms

Question 23

What are the key discoveries of the Scientists?

Question 24

What is the Charge and Location of Subatomic Particles?

Answer 24

Location: Nucleus
Charge: protons (+) and neutrons (0)

Question 25

**Know how determine how many Electrons, Protons, and Neutrons there are in an Atom when given the Atomic Number and Atomic Mass**

Question 26

# * **Know how to draw the Bohr-Rutherford Diagrams and the Lewis Driagrams for the first 20 Elements of the Periodic Table**

Answer 26

Bohr-Rutherford Diagrams * Show electron arrangement in shells. * Example: Sodium (Na) Protons: 11 Neutrons: 12 Electrons: 11 Electron Arrangement: 2, 8, 1

Question 27

# * How does Ionic and Covalent Binding Occur?

Answer 27

**Covalent bonding** involves the sharing of electrons between two or more atoms. **Ionic bonds** form when two or more ions come together and are held together by charge differences.

Question 28

# * How are Ions Formed?

Answer 28

When Atoms lose or gain electrons in order to have a full outer valence electron shells.

Question 29

# * What would an Ions charge be depending on whether they Lose or Gain Electrons?

Answer 29

**Metals (EX: Na, Mg):** Lose electrons→positive ion (cation). **Non-Metals (EX: Cl, O):** Gain electrons →negative ion (anion).

Question 30

# * What is a molecular compound vs. ionic compound?

Answer 30

**Molecular compounds** are compounds made up of nonmetals covalently bonded to each other. **Ionic compounds** are composed of positive and negative ions held together by ionic bonds

Question 31

Ionic compounds tend to be good conductors of electric current, but the light on the conductivity tester in the photograph on the right is not glowing. Why does the ionic compound show not conduct electric current? What could you do to make the light glow?

Answer 31

Ionic compounds are only good conductors when they are dissolved in water. This causes the cations and anions to separate (dissociate) in water and allows these charged particles to float freely, enabling them to conduct an electric current.