$$2 \times 1.01 \text{ g/mol} + 16.00 \text{ g/mol}$$

$$\frac{16.00}{18.02} \times 100 \approx 88.8\%$$

Question 1

Which of the following is the correct abbreviation for the metric unit used to measure mass?

Accepted Answer

kg

Question 2

A student measures the length of a desk as 1.230 meters. How many significant figures are in this measurement?

Accepted Answer

4

Question 3

Which of the following best describes a mixture?

Accepted Answer

A combination of two or more substances that retain their individual properties

Question 4

Which process is an example of a physical change?

Accepted Answer

Melting ice

Question 5

Given the element chlorine (Cl), which group and period does it belong to on the periodic table?

Accepted Answer

Group 17, Period 3

Question 6

Which of the following electron configurations represents a noble gas?

Accepted Answer

$$1s^2$$ $$2s^2$$ $$2p^6$$

Question 7

Which statement best explains why sodium (Na) reacts vigorously with water?

Accepted Answer

Sodium easily loses one electron to achieve a stable configuration

Question 8

What is the correct formula for calculating the molar mass of water ($$H_2O$$)?

Accepted Answer

$$2 	imes 1.01 	ext{ g/mol} + 16.00 	ext{ g/mol}$$

Question 9

A compound contains 40% carbon, 6.7% hydrogen, and 53.3% oxygen by mass. What is its empirical formula?

Accepted Answer

$$CH_2O$$

Question 10

Which of the following is a balanced chemical equation for the combustion of methane ($$CH_4$$)?

Accepted Answer

$$CH_4 + 2O_2$$ \rightarrow $$CO_2 + 2H_2O$

Question 11

If 2.0 moles of $$H_2$$ react with excess $$O_2 to $$produce water, how many grams of $$H_2O$$ are formed? ($$H_2O$$ molar mass = 18.0 g/mol)

Accepted Answer

36.0 g

Question 12

Which type of radiation is the most penetrating and requires lead shielding for protection?

Accepted Answer

Gamma radiation

Question 13

Which equation represents the nuclear reaction for beta decay?

Accepted Answer

$$^{14}_{6}C \$$rightarrow ^{14}$$_{7}N + \$$beta^{-}$$

Question 14

Which of the following best describes the difference between fission and fusion?

Accepted Answer

Fission splits a heavy nucleus; fusion combines light nuclei

Question 15

A solution contains 0.5 moles of NaCl dissolved in 500 mL of water. What is the molarity of the solution?

Accepted Answer

1.0 M

Question 16

Which of the following is a binary ionic compound?

Accepted Answer

NaCl

Question 17

Which of the following best explains why noble gases are chemically inert?

Accepted Answer

They have a full valence electron shell

Question 18

What is the percent composition of oxygen in $$H_2O$$?

Accepted Answer

$$\frac{16.00}{18.02} 	imes 100 \approx 88.8\%$$

Question 19

Which of the following best describes a covalent bond?

Accepted Answer

A bond formed by the sharing of electrons

Question 20

Which of the following is the correct electron configuration for an atom of oxygen?

Accepted Answer

$$1s^2$$ $$2s^2$$ $$2p^4$$

Introduction to Chemistry: 1st Semester Midterm Review Study Notes

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