$$2.41 \times 10$$^{24}$$ molecules

$$3.01 \times 10$$^{24}$$ atoms

One mole of any substance contains $$6.02 \times 10$$^{23}$$ particles.

Question 1

Which of the following best describes a mole in chemistry?

Accepted Answer

A unit that defines 6.02 x $$10^{23}$$ items, known as Avogadro's number.

Question 2

How many molecules are present in 4.0 moles of water ($$H_2O$$)?

Accepted Answer

$$2.41 	imes 10$$^{24}$$ molecules

Question 3

Which group in the periodic table does a metal X belong to if it forms an ionic compound with fluorine with the formula $$XF_3$$?

Accepted Answer

Group 3A

Question 4

Calculate the number of atoms in 5.0 moles of carbon ($$C).$$

Accepted Answer

$$3.01 	imes 10$$^{24}$$ atoms

Question 5

How many moles are present in $$1.204 	imes 10$$^{24}$$ atoms of silver (Ag$)?

Accepted Answer

2.00 moles

Question 6

What is the molar mass of $$CaCl_2$$?

Accepted Answer

110.98 g/mol

Question 7

How many hydrogen atoms are present in one formula unit of $$(NH_4$)_2SO_4$$?

Accepted Answer

8

Question 8

Which of the following is the correct chemical formula for dihydrogen sulfide?

Accepted Answer

$$H_2S$$

Question 9

Calculate the molar mass of ethanol ($$C_2H_5OH). ($$Atomic masses: C = 12.01, H = 1.01, O = 16.00)

Accepted Answer

46.08 g/mol

Question 10

A sample contains $$3.01 	imes 10$$^{23}$$ molecules of CO_2$. How many moles of CO_2$ are present?

Accepted Answer

0.50 mol

Question 11

Which of the following statements about the mole is TRUE?

Accepted Answer

One mole of any substance contains $$6.02 	imes 10$$^{23}$$ particles.

Question 12

What is the formula mass of $$MgSO_4$$? (Atomic masses: Mg = 24.31, S = 32.06, O = 16.00)

Accepted Answer

120.37 amu

Question 13

Which of the following best describes the relationship between formula mass and molar mass?

Accepted Answer

The formula mass in amu is numerically equal to the molar mass in g/mol.

Question 14

How many oxygen atoms are present in one formula unit of $$Al_2$$($$CO_3)_3$?

Accepted Answer

9

Question 15

A box contains a dozen donuts. If you have 3 boxes, how many donuts do you have? (Relate this to the mole concept.)

Accepted Answer

36 donuts

Question 16

Which of the following is the correct molar mass for ammonium chloride ($$NH_4Cl$$)?

Accepted Answer

53.50 g/mol

Question 17

If you have $$2.11 	imes 10$$^{24}$$ atoms of H_2$, how many moles do you have?

Accepted Answer

3.50 mol

Question 18

Which of the following is NOT a correct chemical formula?

Accepted Answer

$$NaCl_2$$

Question 19

What is the total number of atoms in one molecule of $$C_2H_5OH$$?

Accepted Answer

9

Question 20

Which of the following best explains why the mole is a useful unit in chemistry?

Accepted Answer

It allows chemists to count atoms and molecules by weighing them.

Chemical Quantities, The Mole, and Molar Mass: Study Notes for General Chemistry

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