Question 1

Which of the following best describes a chemical change, as opposed to a physical change?

Accepted Answer

Iron rusting when exposed to air

Question 2

A sample of ethanol has a mass of 46.0 g and a volume of 58.0 mL. What is its density in $$\mathrm{g/mL}$$? (Round to the correct number of significant digits.)

Accepted Answer

$$0.793\ \mathrm{g/mL}$$

Question 3

Which of the following statements about the scientific method is CORRECT?

Accepted Answer

Experiments are used to test hypotheses.

Question 4

Which of the following is the correct electron configuration for a neutral atom of sodium ($$\mathrm{Na}$$, atomic number 11)?

Accepted Answer

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

Question 5

A solution is prepared by dissolving $$15.0\ \mathrm{g} of $$NaCl in enough water to make $$250.0\ \mathrm{mL} of $$solution. What is the percent (m/v) concentration of NaCl in the solution?

Accepted Answer

$$6.0\%$$

Question 6

Which of the following best explains why water has a relatively high boiling point compared to other molecules of similar size?

Accepted Answer

Water molecules form hydrogen bonds with each other.

Question 7

Which of the following compounds is an electrolyte when dissolved in water?

Accepted Answer

NaCl

Question 8

A sample of gas occupies $$4.00\ \mathrm{L} at$$ $$1.00\ \mathrm{atm}$$ and $$300\ \mathrm{K}. If $$the pressure is increased to $$2.00\ \mathrm{atm}$$ and the temperature is decreased to $$150\ \mathrm{K}$$, what is the new volume? (Assume ideal gas behavior.)

Accepted Answer

$$1.00\ \mathrm{L}$$

Question 9

Which of the following is the correct formula for calcium phosphate, given that calcium forms $$\mathrm{Ca$$^{2+}$$}$$ ions and phosphate is $$\mathrm{PO_4$^{3-}}$$?

Accepted Answer

$$\mathrm{Ca_3$(PO_4$)_2}$$

Question 10

Which of the following statements about acids and bases is TRUE?

Accepted Answer

A base decreases the concentration of $$\mathrm{H^+} in $$solution.

Question 11

Which of the following is a correct balanced equation for the neutralization of hydrochloric acid with sodium hydroxide?

Accepted Answer

$$\mathrm{HCl\ +\ NaOH\ \rightarrow\ NaCl\ +\ H_2O}$$

Question 12

Which of the following best describes the role of a buffer in a biological system?

Accepted Answer

A buffer maintains a relatively constant pH when small amounts of acid or base are added.

Question 13

Which of the following is the correct IUPAC name for $$\mathrm{CO_2$}$$?

Accepted Answer

Carbon dioxide

Question 14

How many moles are present in $$18.0\ \mathrm{g} of $$water ($$\mathrm{H_2O}$$)? (Molar mass of $$\mathrm{H_2O} is$$ $$18.0\ \mathrm{g/mol})$$

Accepted Answer

$$1.00\ \mathrm{mol}$$

Question 15

Which of the following is a characteristic of an alkene?

Accepted Answer

Contains at least one carbon-carbon double bond

Question 16

Which of the following best describes osmosis?

Accepted Answer

The movement of water across a semipermeable membrane from low solute concentration to high solute concentration

Question 17

Which of the following is the correct formula for the compound formed between aluminum and oxygen?

Accepted Answer

$$\mathrm{Al_2O_3}$$

Question 18

A patient receives an intravenous solution containing $$0.90\% (m/v) $$NaCl. What is the mass of NaCl in $$500.0\ \mathrm{mL} of $$this solution?

Accepted Answer

$$4.5\ \mathrm{g}$$

Question 19

Which of the following best explains why noble gases are generally unreactive?

Accepted Answer

They have a complete valence electron shell.

Question 20

Which of the following is a correct statement about the conservation of matter in a chemical reaction?

Accepted Answer

The total mass of reactants equals the total mass of products.

GOB Chemistry Study Guide: Key Topics and Concepts (Timberlake, 14th Edition)

Guida di studio - Domande di pratica

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