Question 1

Which of the following best describes the difference between a physical change and a chemical change?

Accepted Answer

A chemical change results in the formation of new substances, while a physical change does not alter the chemical identity.

Question 2

A sample of gas occupies $$2.50\ \mathrm{L} at$$ $$1.00\ \mathrm{atm}$$ and $$300\ \mathrm{K}. $$What will be its volume at $$2.00\ \mathrm{atm}$$ and $$400\ \mathrm{K}$$? (Assume ideal gas behavior.)

Accepted Answer

$$1.67\ \mathrm{L}$$

Question 3

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 4

A student mixes $$50.0\ \mathrm{g} of $$water at $$80.0\ ^\circ\mathrm{C}$$ with $$50.0\ \mathrm{g} of $$water at $$20.0\ ^\circ\mathrm{C}. $$What is the final temperature of the mixture? (Assume no heat loss to the surroundings.)

Accepted Answer

$$50.0\ ^\circ\mathrm{C}$$

Question 5

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

Accepted Answer

Ice is less dense than liquid water because its molecules are arranged in a crystalline structure with more open space.

Question 6

Which of the following is the correct electron configuration for a neutral atom of sodium ($$Z=11$$)?

Accepted Answer

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

Question 7

A balloon filled with helium has a volume of $$4.00\ \mathrm{L} at$$ $$25.0\ ^\circ\mathrm{C}$$ and $$1.00\ \mathrm{atm}. If $$the temperature is increased to $$50.0\ ^\circ\mathrm{C} at $$constant pressure, what is the new volume?

Accepted Answer

$$4.33\ \mathrm{L}$$

Question 8

Which of the following best describes the relationship between temperature and kinetic energy of gas particles?

Accepted Answer

As temperature increases, the average kinetic energy of gas particles increases.

Question 9

Which of the following is a chemical property?

Accepted Answer

Reactivity with oxygen

Question 10

A $$10.0\ \mathrm{g}$$ sample of a compound contains $$4.0\ \mathrm{g} of $$carbon, $$1.0\ \mathrm{g} of $$hydrogen, and $$5.0\ \mathrm{g} of $$oxygen. What is the percent by mass of hydrogen in the compound?

Accepted Answer

$$10\%$$

Question 11

Which of the following statements about ionic and covalent compounds is correct?

Accepted Answer

Ionic compounds conduct electricity when dissolved in water, while covalent compounds generally do not.

Question 12

Which of the following is the correct formula for aluminum sulfate?

Accepted Answer

$$\mathrm{Al}_2\left(\mathrm{SO}_4\right)_3$$

Question 13

A $$2.00\ \mathrm{mol}$$ sample of an ideal gas is at $$1.00\ \mathrm{atm}$$ and $$273\ \mathrm{K}. $$What is its volume? ($$R = 0.0821\ \mathrm{L\cdot atm\cdot $$mol^{-1}$$\cdot K$$^{-1}$$})$$

Accepted Answer

$$44.8\ \mathrm{L}$$

Question 14

Which of the following best describes the trend in atomic radius across a period in the periodic table?

Accepted Answer

Atomic radius decreases from left to right.

Question 15

Which of the following is a correct statement about the law of conservation of mass?

Accepted Answer

The total mass of reactants equals the total mass of products in a chemical reaction.

Question 16

Which of the following is the correct balanced equation for the combustion of methane ($$\mathrm{CH}_4$$)?

Accepted Answer

$$\mathrm{CH}_4 + 2\mathrm{O}_2 \rightarrow \mathrm{CO}_2 + 2\mathrm{H}_2\mathrm{O}$$

Question 17

Which of the following best explains why salt (NaCl) dissolves in water?

Accepted Answer

The positive and negative ions in NaCl are attracted to the partial charges on the polar water molecules.

Question 18

Which of the following is the correct name for $$\mathrm{Fe}_2\mathrm{O}_3$$?

Accepted Answer

Iron(III) oxide

Question 19

A solution is prepared by dissolving $$10.0\ \mathrm{g} of $$NaCl in enough water to make $$500.0\ \mathrm{mL} of $$solution. What is the molarity of the solution? ($$\mathrm{NaCl}$$ molar mass $$= 58.44\ \mathrm{g/mol})$$

Accepted Answer

$$0.342\ \mathrm{M}$$

Question 20

Which of the following best describes the difference between an endothermic and an exothermic reaction?

Accepted Answer

Endothermic reactions absorb heat, while exothermic reactions release heat.

Introduction to Chemistry: Final Exam Review Guide Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard