7a chemistry review. 1. all matter is made up of atoms

7A Chemistry Review

1. All matter is made up of

ATOMS.

2. Identify each labeled structure in the atom. Describe the charge for each particle.

A

B

C

A – ElectronElectrons have a negative charge.

B – NeutronNeutrons have no charge (neutral).

C - ProtonProtons have a positive charge.

3.Where are protons and neutrons found in an atom?

4. Where are electrons found in an atom?

In the nucleus of an atom.

Outside the nucleus of an atom.

5. Which subatomic particle would be found outside the nucleus of an atom?

ELECTRON

6. A positively charged particle is a

PROTON.

7. Which of the following is not an element?

1. oxygen 3. sodium chloride

2. hydrogen 4. nitrogen

3

8. A chemical formula like CO2 represents

1.an element 3. an atom   

2.an electron  4. a compound 4

9. A substance made up of two or more elements that have been chemically combined is a

COMPOUND.

10. A substance made up of two or more elements that have been physcially combined is a

MIXTURE.

11. A substance that cannot be changed into simpler substances by a chemical change is called a (an)

1. element. 3. liquid.2. solid. 4. mixture.1

12. Element or Compound?a. Carbon (C)b. Carbon dioxide (CO2)

c. Water (H2O)

d. Nitrogen (N)e. Glucose (C6H12O6)

elementcompound

compound

elementcompound

13.

3

Oxygen and hydrogen

14.

6

15.

16. Label the following diagrams:• Compound, element, mixture

A B C D

element

element

mixture

compound

17. In sweetened tea, the sugar is called the

1. solute. 3. solvent. 2. element. 4. solution.

1

18. Which of the following would help sugar dissolve faster in water?

1.stirring the water2.decreasing the solubility of

sugar3.using larger particles of

sugar4.decreasing the water

temperature1

19. Describe the difference between a soluble and insoluble substance.

A soluble substance easily dissolves in a solvent.

An insoluble substance DOES NOT dissolve in a solvent.

20. Sand and iron particles that are similar in size and color are mixed together in a beaker. What would be the best method of separating the particles?

1. Use tweezers to separate them. 2. Add water to the mixture.3. Use a magnet to separate them. 4. Pour the mixture into a filter. 3

Heat up the water.

Stir the solution.

Crush the sugar cube (increase its surface area).

21.

22. The substances in a mixture can be separated by physical means because

1. no chemical change occurs when the substances are combined.

2. the physical and chemical properties of the substances change.

3. none of the properties of the substances change.

4. the chemical, but not the physical, properties of the substances change.

1

23. Describe the term ‘solubility.’• The amount of solute that

can dissolve in a solvent24. Describe at least three factors

that can affect the solubility of a substance.

• Temperature, surface area, stirring

25. Which of the following would help sugar dissolve faster in water?

a. stirring, the waterb. decreasing the solubility of

sugarc. using larger particles of sugard. decreasing the water

temperature a

Heat up the water.

As temperature increases, the solubility of the gas decreases.

Heat up the solvent, increase the surface area, stir the solution.

26.

36 g

27.

3

28. For the following pictures, identify whether a physical or chemical change is occurring.

Physical

Chemical

Chemical

Physical

Physical

Chemical

Heat (thermal energy)

Tem

pera

ture

º C

.

100

0

A

B

C

DE

Identify substances A, C and E.

A – solid C – liquid E - gas

29.

Heat (thermal energy)

Tem

pera

ture

º C

.

100

0

A

B

C

DE

melting

freezing

condensing

evaporation

2

1

4

3

Identify processes 1, 2, 3 and 4.

1 – melting 2 – freezing 3 – vaporization 4 - condensation

30.

The chemical composition of the can did not change. It is still made of aluminum.

31.

32. Identify the different phases of matter.

• Solid, liquid, gas, plasma33. The particles of a substance

are closest together in a _____.• solid34. The particles of a substance

that does not have a definite volume or shape is ____.

• gas

35. Identify the different phases of matter, shown in the diagram below.

A B C

gas liquid

solid

36. The particles of a substance are closest together in a

____.

• solid

37. The particles of a substance that does not have a

definite volume or shape is ______.

• gas

38. When a liquid becomes a solid, heat is ____ and the

process is called_________.

• Released, freezing

39. ______ is the process in which liquid changes to gas. 

• evaporation

40. Matter is anything that has and _________.

• Mass and volume

41. Identify the following as a physical or chemical change:

a. Bending a Paper Clip.

• physical

b. Melting ice into water.

• physical

c. Baking a cake batter into a cake.

• chemical

d. The rusting of a nail

• chemical

solid liquid

42.

43.

44.

3

3

45.

2

46. Identify the solid, liquid and gas! Support your answer.

Gas

- Atoms are very loosely packed

Solid

- Atoms are tightly packed

Liquid

- Atoms are loosely packed

47. Identify the phase change described. a. Solid to liquid:b. Gas to liquid:c. Liquid to solid: d. Solid to gas: e. Liquid to gas:

melting

condensationfreezing

sublimationevaporation

48. For each phase change describe whether energy is RELEASED or ABSORBED. a. Melting: b. Freezing:c. Vaporization: d. Sublimation: e. Condensation:

ABSORBEDRELEASED

ABSORBED

ABSORBED RELEASED

49. The particles of a substance are closest together in

1.a solid 2.a liquid 3.a gas 4.plasma 1

50. The particles of a substance move most readily in

1.a solid 2.a liquid 3.a gas

3

51. The particles of a substance that does not have a definite volume or shape is

1.a solid 2. a liquid 3. a gas 3

52. When a liquid becomes a solid, energy

1.does not change2.is released3.is absorbed4.is first absorbed, then

released 2

53. _______ is the process in which liquid changes to gas.

1. Sublimation 3. Condensation

2. Evaporation4. Combustion2

54. The change of a liquid to a solid is called

1. freezing 3. melting2. sublimation 4. vaporization

1

55. When substances go directly from the solid phase to the gas phase, the phase change is called

1. sublimation 2. condensation

3. evaporation 4. vaporization 1

Temperature (oC)

Time (minutes)

18

100

4 16

56. In this experiment, how long did it take for the water to start boiling?

Why didn’t the temperature of the

water increase after 4 minutes?

How long did it take for all the water to

turn into steam?

4 minutes

The energy was being used to separate the

water molecules and turn the liquid into a

gas.

12 minutes

liqui

d

57. What happens to the position of water molecules as they lose heat energy?

• The slow down and move closer together.

a. Atomic mass:•79.9b. Mass number:•80c. # of protons:•35d. # of electrons:•35e. # neutrons:•45f. Atomic #:•35

58.

59. a. Atomic mass:•112.41b. Mass number:•112c. # of protons:•48d. # of electrons:•48e. # neutrons:•64f. Atomic #:•48

60. All samples of an element are composed of atoms with the same

1.atomic mass 2.atomic number 3.number of protons and neutrons

4.number of neutrons 2

3Li

Lithium6.94

1H

Hydrogen1.01

14Si

Silicon28.09

18Ar

Argon39.95

1. What is the atomic number for lithium?

2. How many protons does an atom of Si have?

3. What is the atomic mass for Argon?

4. How many electrons does an atom of H have?

5. How many neutrons are in an atom of Li?

6. How many electrons are in an atom of Si?

7. How many protons and neutrons are in an atom of Argon?

3

14

39.95

1

4

14

40

61.

62.

4

63.

64.

3

2

65. Explain how the periodic table of elements is arranged.

• They are arranged according to atomic number.

66. Elements at the left of the periodic table are known as ______.

• metals67. Elements at the right of the periodic

table are known as _______.• nonmetals

68. Explain some of the properties of metals.

• They are malleable, ductile, have luster, and are good conductors of heat and electricity

69. Explain some of the properties of nonmetals.

• They are brittle, have no luster and they are not good conductors of heat and electricity.

Cd, Cu

Br, P

Group 18

70.

a.b.

c.

71.

2

a. I am a member of the Boron family with 49 protons.

b. I have a total of 74 electrons in an atom.

c. I have an atomic mass of 55.847.

d. I have 8 neutrons in an atom.

In

W

Fe

O

72. Use a periodic table to help you identify each element. Give its symbol for the answer.

The elements oxygen, sulfur, selenium and tellurium are all found in the same group (16) on the table. What do we know about the elements in that family?

They have the same (BUT NOT IDENTICAL) properties.

73.

a. In what family is neon found?b. What do we call those elements in that

group?

Family 18

Noble gases

74.

Which element is a metalloid?1. S (Sulfur) 3. Si (Silicon) 2. Ba (Barium) 4. Br (Bromine)

75.

3

Explain what occurs to the atomic number when moving from left to right on the periodic table.

Atomic number increases.

76.

Fill in the correct number for each letter using the information provided.

ElementAtomic Number

Atomic Mass

# of Protons

# of Neutron

s

# of Electron

s

Mg 12 24 A B C

P 15 D E 16 F

K G 39 H I 19

A B C

D E F

G H I

77.

The answers are …

ElementAtomic

#Atomic Mass

ProtonsNeutron

sElectron

s

Mg 12 24 A B C

P 15 D E 16 F

K G 39 H I 19

12 12 12

31 15 15

19 19 20

78. Which three elements have the most similar chemical properties?

1.Ar, Kr, Br 2.K, Rb, Cs 3.B, C, N 4.O, N, Si

1

79. Which element is a noble gas?

1.hydrogen2.oxygen3.neon4.nitrogen

2

80. Explain the difference between an acid and a base.

• An acid has an excess of H+ ions and a base has an excess of OH- ions.

81. Identify 2 examples of acids.• Hydrochloric acid, lemon juice82. Identify 2 examples of bases.• Soap, drain cleaner83. What does the pH scale measure?• The strength of an acid or base.

84. What does it mean when a substance is neutral?

• It is not an acid or a base.85. What pH would neutral substance

have?• 786. Which numbers on the pH scale

represent an acid?• Any number below 7.

87. Classify each of the following as acidic, neutral, or basic

a) pH = 2.3

b) pH = 6.5

c) pH = 8.5

d) pH = 11.7

e) pH = 13.4

f) pH = 7.0

acidic

acidic

basic

basic

basic

neutral

88. Use the solubility curves below to answer the following questions.

c. How many grams of NH4Cl can dissolve in 100 grams of water at 25°C?

b. Identify the solvent represented on this graph.

a. Identify the solutes represented on this graph.

d. How many grams of HCl can dissolve in 100 grams of water at 10°C?

HCl and NH4Cl

water

40 grams

76 grams

Use the solubility curves below to answer the following questions. e. At what temperature can

70 grams of NH4Cl dissolve in 100 grams of water?

f. Explain the relationship between temperature and the solubility of HCl (gas).

85°C

As temperature increases, the solubility of HCl decreases.

g. Explain the relationship between temperature and the solubility of NH4Cl (solid).

As temperature increases, the solubility of NH4Cl increases.