Latest CHEM 120 Week 1 to

Latest / | CHEM 120 Week 1 to Week 7 Quizzes

1. Question : (TCO 2) The atomic number of an atom is equal to the number of

Student Answer:

electrons plus protons.

nuclei.

neutrons plus protons.protons.neutrons.Instructor Chapter 3; The atomic number = number of protons

Explanation:

1921547766 MultipleChoice 2 True

• 1921547766 MultipleChoice 2
• Question : (TCO 2) Consider a neutral atom with 30 protons and 34 neutrons. The

atomic number of the element is

Student

Answer: 94.

30.

64.

32.

34.Instructor Chapter 3; Atomic number = number of protons. Therefore, in this case, the atomic

Explanation: number = 30.

1921547767 MultipleChoice 5

• 1921547767 MultipleChoice 5

3. Question : (TCO 2) No matter how much extra oxygen is available, 12 grams of

carbon always combines with 32 grams of oxygen. This best illustrates the law of

Student Answer:

conservation of mass. 1 / 4

multiple proportions.definite proportions.All of the above None of the above

Instructor Explanation: Chapter 2

MultipleChoice 8 False

1921547768 8

4. Question : (TCO 2) Which type of radioactivity has a negative charge?

Student Answer:

Alpha

Beta Gamma All of the above

None of the above

Instructor Explanation: Chapter 3

1921547769 MultipleChoice 11 True

• 1921547769 MultipleChoice 11

5. Question : (TCO 2) The proton has

Student Answer:

the same mass and charge as the electron.

a smaller mass and the same charge as the electron.a smaller mass and opposite charge as the electron.a larger mass and opposite charge as the electron.None of the above

Instructor Explanation: Chapter 3

1921547770 MultipleChoice 18 True

• / 4

• 1921547770 MultipleChoice 18

6. Question : (TCO 2) Isotopes are atoms of the same element with

Student Answer:

a different number of neutrons.

a different number of electrons.a different number of protons.different atomic numbers.None of the above

Instructor Explanation: Chapter 3

1921547771 MultipleChoice 22 False

• 1921547771 MultipleChoice 22

7. Question : (TCO 2) The atomic number of an element is

Student Answer:

the number of protons in an atom.

equal to the positive charge of an atom’s nucleus.equal to the number of electrons in a neutral atom.All of the above are valid definitions.None of the above

Instructor Explanation: Chapter 3

1921547772 MultipleChoice 21 False

• 1921547772 MultipleChoice 21

8. Question : (TCO 1) How many meters are in 7 yards? Show your work.

Student Answer: x meters = 7 yd x (0.914 m/1 yd) = 6.4 m

Instructor x meters = 7 yd x (0.914 m/1 yd) = 6.4 m (Chapter 1; 1 point for units, 1 point

Explanation: for conversion factor, 1 point for answer)

1921547773 Short 3 False

• 1921547773 Short 3

9. Question : (TCO 1) How many quarts are in 12.5 liters? Show your work.

• / 4

Student Answer: x qts = 12.5 L x (1 qt/0.946 L) = 13.2 L

Instructor x qts = 12.5 L x (1 qt/0.946 L) = 13.2 L (Chapter 1; 1 point for units, 1 point for

Explanation: conversion factor, 1 point for answer)

1921547774 Short 8 False

• 1921547774 Short 8

10. Question : (TCO 1) What is the mass of 53 mL of ethyl alcohol, which has a

density of 0.79 g/mL? Show your work.

Student Answer: x g = 53 mL x (0.79 g/mL) = 42 g

Instructor x g = 53 mL x (0.79 g/mL) = 42 g (Chapter 1; 1 point for units, 1 point for

Explanation: conversion factor, 1 point for answer)

1921547775 Short 10 False

• 1921547775 Short 10

11. Question : (TCO 1) What is the mass of 74 mL of ethyl alcohol, which has a

density of 0.79 g/mL? Show your work.

Student Answer: x g = 74 mL x (0.79 g/mL) = 58.5 g

Instructor x g = 74 mL x (0.79 g/mL) = 58.5 g (Chapter 1; 1 point for units, 1 point for

Explanation: conversion factor, 1 point for answer)

1921547777 Short 14 False

• 1921547777 Short 14
• Question : (TCO 2) Determine the number of protons, neutrons, and electron for

the element shown below. The mass number for the isotope of this element is 90. You must show your work for each determination to receive credit (2 points per determination).

40 Zr 91.22

Student Answer: Atomic # 40

Protons 40 Electron 40 Electron mass number 90- 40 protons = 50 electrons Instructor Chapter 3; The atomic number from the periodic table of elements = 40.Explanation: Therefore, the # of protons = 40 (2 points). The # of protons = number of electron; thus = 40 electrons (2 points). If the mass number is 90, then there are 50 neutrons (# neutrons = mass number - # protons).

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