Question 1

A 100.0 g sample of a radioactive isotope decays with a half-life of 6 hours. How much of the sample remains after 18 hours?

Accepted Answer

$$12.5\ \mathrm{g}$$

Question 2

Which of the following best describes the molecular geometry of $$\mathrm{CO_2$}$$?

Accepted Answer

Linear

Question 3

A student measures the mass of a sample as $$12.30\ \mathrm{g}$$ and its volume as $$8.2\ \mathrm{mL}. $$What is the density of the sample, reported with the correct number of significant figures?

Accepted Answer

$$1.5\ \mathrm{g/mL}$$

Question 4

Which of the following compounds contains a polar covalent bond?

Accepted Answer

$$\mathrm{HCl}$$

Question 5

A solution is prepared by dissolving $$20.0\ \mathrm{g} of $$NaOH in enough water to make $$500.0\ \mathrm{mL} of $$solution. What is the molarity of the solution? $$(\mathrm{M_{NaOH}} = 40.0\ \mathrm{g/mol})$$

Accepted Answer

$$0.50\ \mathrm{M}$$

Question 6

Which of the following statements about isotopes is correct?

Accepted Answer

Isotopes have the same number of protons but different numbers of neutrons.

Question 7

Which of the following molecules can form hydrogen bonds with water?

Accepted Answer

$$\mathrm{NH_3$}$$

Question 8

A gas occupies $$2.50\ \mathrm{L} at$$ $$1.00\ \mathrm{atm}$$ and $$25^\circ\mathrm{C}. $$What volume will it occupy at $$2.00\ \mathrm{atm}$$ and $$25^\circ\mathrm{C}$$, assuming ideal behavior?

Accepted Answer

$$1.25\ \mathrm{L}$$

Question 9

Which of the following is a double replacement (metathesis) reaction?

Accepted Answer

$$\mathrm{$$AgNO_3$$ + NaCl \rightarrow AgCl + $$NaNO_3$$}$$

Question 10

Which of the following best explains why ice floats on water?

Accepted Answer

Ice is less dense than liquid water due to hydrogen bonding.

Question 11

What is the empirical formula for a compound containing $$52.2\%$$ carbon, $$13.0\%$$ hydrogen, and $$34.8\%$$ oxygen by mass?

Accepted Answer

$$\mathrm{C_2H_6O}$$

Question 12

Which of the following solutions has the highest concentration of hydronium ions?

Accepted Answer

$$\mathrm{pH} = 2.0$$

Question 13

Which of the following is a physical change?

Accepted Answer

Melting of ice

Question 14

How many moles of $$\mathrm{CO_2$}$$ are produced when $$10.0\ \mathrm{g} of$$ $$\mathrm{C_2H_5OH} ($$ethanol, $$M = 46.0\ \mathrm{g/mol}) is $$completely combusted? $$\mathrm{C_2H_5OH} + 3O_2 \rightarrow 2CO_2 + 3H_2O$$

Accepted Answer

$$0.435\ \mathrm{mol}$$

Question 15

Which of the following best describes the electron configuration of $$\mathrm{Na^+}$$?

Accepted Answer

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

Question 16

A $$50.0\ \mathrm{mL}$$ sample of $$6.00\ \mathrm{M}$$ HCl is diluted to a final volume of $$300.0\ \mathrm{mL}. $$What is the final concentration?

Accepted Answer

$$1.00\ \mathrm{M}$$

Question 17

Which of the following is the correct name for $$\mathrm{K_2SO_4}$$?

Accepted Answer

Potassium sulfate

Question 18

Which of the following best describes the functional group present in acetic acid?

Accepted Answer

Carboxylic acid

Question 19

Which of the following statements about gases is TRUE?

Accepted Answer

The pressure of a gas is due to collisions of the gas molecules.

Question 20

A $$2.00\ \mathrm{mol}$$ sample of $$\mathrm{O_2$}$$ gas is at $$27^\circ\mathrm{C}$$ and $$2.00\ \mathrm{atm}. $$What is its volume? $$(R = 0.0821\ \mathrm{L\ atm\ $$mol^{-1}$$\ K$$^{-1}$$})$$

Accepted Answer

$$24.6\ \mathrm{L}$$

Chem 1120 Final Exam Study Guide – Step-by-Step Guidance

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