Q: A sample of copper metal is heated from $$25\ ^\circ\mathrm{C} to$$ $$75\ ^\circ\mathrm{C}. If $$the specific heat of copper is $$0.385\ \mathrm{J/g\cdot ^\circ C}$$ and the sample has a mass of $$50\ \mathrm{g}$$, how much heat ($$q) is $$absorbed?

$$q = 0.385 \times 50 \times (75 - 25) = 962.5\ \mathrm{J}$$

Q: A sample contains $$80\%$$ $$^{35}\mathrm{Cl}$$ and $$20\%$$ $$^{37}\mathrm{Cl}. $$What is the average atomic mass of chlorine?

$$(0.80 \times 35) + (0.20 \times 37) = 35.4$$

Question 1

Which of the following is an example of a physical change?

Accepted Answer

Dissolving table salt in water

Question 2

A sample of copper metal is heated from $$25\ ^\circ\mathrm{C} to$$ $$75\ ^\circ\mathrm{C}. If $$the specific heat of copper is $$0.385\ \mathrm{J/g\cdot ^\circ C}$$ and the sample has a mass of $$50\ \mathrm{g}$$, how much heat ($$q) is $$absorbed?

Accepted Answer

$$q = 0.385 	imes 50 	imes (75 - 25) = 962.5\ \mathrm{J}$$

Question 3

Which statement best describes a heterogeneous mixture?

Accepted Answer

A mixture in which the components are not evenly distributed and can be visually distinguished

Question 4

Which element listed below is a metalloid?

Accepted Answer

Silicon (Si)

Question 5

Which of the following best describes the process of sublimation?

Accepted Answer

A solid changing directly into a gas

Question 6

An atom of phosphorus ($$^{31}_{15}\mathrm{P}) $$has:

Accepted Answer

15 protons, 16 neutrons, 15 electrons

Question 7

Which of the following elements is most likely to be a good conductor of electricity?

Accepted Answer

Gold (Au)

Question 8

Which of the following statements about isotopes is correct?

Accepted Answer

Isotopes of an element have the same number of protons but different numbers of neutrons

Question 9

Which electron configuration represents a neutral atom of magnesium (Mg)?

Accepted Answer

$$1s^2$$\ $$2s^2$$\ $$2p^6$$\ $$3s^2$$

Question 10

Which of the following best explains why metals tend to have high electrical conductivity?

Accepted Answer

Metals have delocalized electrons that can move freely throughout the structure

Question 11

A sample contains $$80\%$$ $$^{35}\mathrm{Cl}$$ and $$20\%$$ $$^{37}\mathrm{Cl}. $$What is the average atomic mass of chlorine?

Accepted Answer

$$(0.80 	imes 35) + (0.20 	imes 37) = 35.4$$

Question 12

Which of the following changes is an example of a chemical change?

Accepted Answer

Burning propane in a grill

Question 13

Which of the following statements about the periodic table is correct?

Accepted Answer

Elements in the same group have similar chemical properties

Question 14

Which element is a nonmetal and is essential for respiration in humans?

Accepted Answer

Oxygen (O)

Question 15

Which of the following best describes the atomic theory?

Accepted Answer

Atoms are the smallest units of matter that retain the properties of an element

Question 16

Which of the following elements is most likely to form a positive ion (cation) in chemical reactions?

Accepted Answer

Potassium (K)

Question 17

Which of the following best describes the trend in atomic size across a period from left to right?

Accepted Answer

Atomic size decreases

Question 18

Which of the following is the correct order of electromagnetic radiation from lowest to highest energy?

Accepted Answer

Visible light, ultraviolet, X-rays

Question 19

Which of the following best describes the electron configuration of a noble gas?

Accepted Answer

Completely filled valence shell

GOB Chemistry Study Guide: Matter, Energy, Elements, and Atomic Structure

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