Chemical Composition of the Cell Practice Quiz (6 questions)

1. Regarding the smallest particles of substances, which statements are correct?

A. The smallest particle of a substance, in this definition, is an atom.

B. A molecule is the chemically indivisible largest particle of a substance.

C. An atom is the chemically indivisible smallest particle of a substance.

D. An atom is considered chemically indivisible within a substance.

E. An atom is a group of particles joined by chemical bonds.

Answer: (A), (C), (D)

Explanation

An atom is defined as the chemically indivisible smallest particle of a substance, not the largest particle. A molecule consists of bonded atoms, not a single atom by definition; the description of a bonded group applies to molecules. An atom is not a group of particles joined by chemical bonds.

2. A particle consists of several atoms joined together by chemical bonds. Which statements describe molecules correctly?

A. A molecule consists of atoms joined by chemical bonds.

B. A molecule consists of atoms joined by nuclear bonds.

C. Chemical bonds joining atoms are characteristic of a molecule.

D. A bonded collection of atoms is described as a molecule.

E. A molecule consists of atoms held together by physical mixtures.

Answer: (A), (C), (D)

Explanation

A molecule is made of atoms joined by chemical bonds, so a bonded collection of atoms is a molecule. Physical mixtures and nuclear bonds do not match the definition of a molecule.

3. Molecules belonging to one particular substance share which characteristics?

A. Molecules of that substance have matching atom types and counts.

B. They contain the same kinds but different numbers of atoms.

C. Their atoms occur in the same kinds and quantities.

D. They contain different kinds but the same numbers of atoms.

E. They contain the same kinds and numbers of atoms.

Answer: (A), (C), (E)

Explanation

Molecules of a given substance have the same kinds and numbers of atoms, so their atom types and counts match. Changing either the kinds or the numbers would not describe the stated shared composition.

4. An element is distinguished by which composition?

A. An element consists of several kinds of bonded atoms.

B. An element consists of only one kind of atom.

C. An element consists of atoms from different elements.

D. An element is a substance containing different atom kinds.

E. An element is a substance made from one atom kind.

Answer: (B), (E)

Explanation

An element consists of only one kind of atom, as the correct statements describe. A substance made from atoms of different elements is a chemical compound, not an element.

5. Which descriptions correctly characterize a chemical compound?

A. A chemical compound consists of atoms from the same element.

B. A chemical compound is made from atoms of different elements.

C. Atoms from different elements make up a chemical compound.

D. A substance made from different elemental atoms is a compound.

E. A chemical compound consists of one kind of atom.

Answer: (B), (C), (D)

Explanation

A chemical compound is a substance made from atoms of different elements, as reflected by the correct descriptions. A substance consisting of one kind of atom is an element rather than a compound.

6. Which ingredient combinations match the stated compositions of familiar substances?

A. Table salt consists of sodium and chlorine.

B. Chalk consists of calcium, hydrogen, and oxygen.

C. Sugar consists of calcium, carbon, and oxygen.

D. Sugar consists of carbon, hydrogen, and nitrogen.

E. Table salt consists of sodium and oxygen.

Answer: (A)

Explanation

Table salt consists of sodium and chlorine. The other combinations substitute ingredients: sugar contains carbon, hydrogen, and oxygen, while chalk contains calcium, carbon, and oxygen.