Question 1

Which of the following best describes a homogeneous mixture?

Accepted Answer

A mixture in which the composition is uniform throughout, such as salt dissolved in water.

Question 2

A student measures the mass of a metal sample as 12.34 g, 12.36 g, and 12.35 g in three trials. The true mass is 12.50 g. Which statement best describes the measurements?

Accepted Answer

The measurements are precise but not accurate.

Question 3

Which of the following statements about significant figures is correct?

Accepted Answer

Zeros between nonzero digits are always significant.

Question 4

A sample of ethanol has a mass of 46.0 g and a volume of 58.0 mL. What is its density, reported with the correct number of significant figures?

Accepted Answer

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

Question 5

Which of the following best illustrates the Law of Constant Composition?

Accepted Answer

Water from any source always contains hydrogen and oxygen in a 2:1 ratio by atoms.

Question 6

An atom of $$^{35}_{17}\mathrm{Cl}$$ has how many neutrons?

Accepted Answer

$$18$$

Question 7

Which group in the periodic table contains elements that are all highly reactive metals?

Accepted Answer

Group IA (Alkali metals)

Question 8

A neutral atom of magnesium has an atomic number of $$12$$ and a mass number of $$24. $$How many electrons does it have?

Accepted Answer

$$12$$

Question 9

Which of the following best explains why sodium forms a $$+1$$ ion and chlorine forms a $$-1$$ ion when they react?

Accepted Answer

Sodium loses one electron to achieve an octet, while chlorine gains one electron to achieve an octet.

Question 10

Which of the following is the correct electron configuration shorthand for a neutral atom of calcium ($$Z=20$$)?

Accepted Answer

$$[\mathrm{Ar}]\ 4s^2$

Question 11

A calorimeter contains $$100.0\ \mathrm{g} of $$water at $$25.0^\circ\mathrm{C}. If$$ $$500.0\ \mathrm{J} of $$heat is added, what is the final temperature of the water? (Specific heat of water $$= 4.18\ \mathrm{J/g\cdot ^\circ C})$$

Accepted Answer

$$26.2^\circ\mathrm{C}$$

Question 12

Which of the following statements about the Bohr model of the atom is correct?

Accepted Answer

Electrons orbit the nucleus in fixed energy levels without radiating energy.

Question 13

Which of the following best describes the difference between a compound and a mixture?

Accepted Answer

A compound has a fixed composition and can only be separated by chemical means, while a mixture can have variable composition and can be separated by physical means.

Question 14

Which of the following is the correct scientific notation for the number $$0.000456$$?

Accepted Answer

$$4.56 	imes 10$$^{-4}$$

Question 15

A sample of an unknown metal has a mass of $$31.5\ \mathrm{g}$$ and displaces $$4.50\ \mathrm{mL} of $$water in a graduated cylinder. What is the density of the metal?

Accepted Answer

$$7.00\ \mathrm{g/mL}$$

Question 16

Which of the following best describes the Law of Conservation of Matter?

Accepted Answer

Matter is neither created nor destroyed in a chemical reaction.

Question 17

Which of the following ions has 10 electrons?

Accepted Answer

$$\mathrm{Na}^+$$

Question 18

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

Accepted Answer

Elements in the same group have similar chemical properties.

Question 19

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

Accepted Answer

They have a complete valence shell, satisfying the octet rule.

Question 20

A student is asked to predict the formula of the compound formed between aluminum and oxygen. What is the correct formula?

Accepted Answer

$$\mathrm{Al}_2\mathrm{O}_3$$

CHE 111: General Chemistry I – Study Guide (Chapters 1–4)

Study Guide - Practice Questions

Study Guide - Flashcards