Question 1

Which of the following best defines a molecule?

Accepted Answer

A group of atoms chemically bonded together.

Question 2

Given the formula $$\mathrm{H_2SO_4}$$, how many atoms are present in one molecule?

Accepted Answer

$$7$$

Question 3

How many oxygen atoms are present in $$2$$ molecules of $$\mathrm{H_2SO_4}$$?

Accepted Answer

$$8$$

Question 4

Which of the following is an example of a pure substance?

Accepted Answer

$$\mathrm{H_2O}$$

Question 5

What distinguishes a mixture from a pure substance?

Accepted Answer

A mixture has variable composition and properties.

Question 6

How many atoms of calcium are present in $$3$$ molecules of $$\mathrm{Ca_3$(PO_4$)_2}$$?

Accepted Answer

$$6$$

Question 7

Which of the following is a correct statement about metallic bonding?

Accepted Answer

It involves a 'sea of electrons' shared among metal atoms.

Question 8

If you have $$2$$ molecules of $$\mathrm{H_2SO_4}$$, how many hydrogen atoms are present?

Accepted Answer

$$4$$

Question 9

Which of the following is a mixture?

Accepted Answer

Steel

Question 10

How many total atoms are present in one molecule of $$\mathrm{C_6H_{12}O_6$}$$?

Accepted Answer

$$18$$

Question 11

Which of the following best describes a eutectic mixture?

Accepted Answer

A mixture with a fixed melting point lower than its components.

Question 12

Which of the following is a simple substance?

Accepted Answer

$$\mathrm{O_2$}$$

Question 13

What is the total number of phosphorus atoms in $$3$$ molecules of $$\mathrm{Ca_3$(PO_4$)_2}$$?

Accepted Answer

$$6$$

Question 14

Which property is constant for a pure substance?

Accepted Answer

Boiling point

Question 15

Which of the following is NOT a characteristic of a mixture?

Accepted Answer

Has a fixed melting point

Question 16

How many oxygen atoms are present in $$3$$ molecules of $$\mathrm{Ca_3$(PO_4$)_2}$$?

Accepted Answer

$$24$$

Question 17

Which of the following is an example of a system with different physical states?

Accepted Answer

A glass of water with ice cubes

Question 18

Which statement is true about the atomicity of $$\mathrm{H_2SO_4}$$?

Accepted Answer

It contains 7 atoms per molecule.

Question 19

Which of the following is a characteristic of a pure substance?

Accepted Answer

Fixed composition

Question 20

If you have $$2$$ molecules of $$\mathrm{C_6H_{12}O_6$}$$, how many hydrogen atoms are present?

Accepted Answer

$$24$$

Atoms, Molecules, Atomicity, and Pure Substances vs. Mixtures

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