Q: Calculate the formula mass of $$\mathrm{Ca(OH)_2} ($$calcium hydroxide). (Atomic masses: Ca = 40, O = 16, H = 1)

$$40 + (2 \times 16) + (2 \times 1) = 74$$

Q: Which of the following best describes the relationship between the mole, Avogadro's number, and mass?

One mole of any substance contains $$6.022 \times 10$$^{23}$$ particles and has a mass equal to its molar mass in grams.

Q: How many oxygen atoms are present in $$2.5$$ moles of $$\mathrm{H_2SO_4}$$?

$$2.5 \times 4 \times 6.022 \times 10$$^{23}$$

Q: What is the molar mass of $$\mathrm{Na_2CO_3}$$? (Atomic masses: Na = 23, C = 12, O = 16)

$$2 \times 23 + 12 + 3 \times 16 = 106 g/$$mol

Question 1

Which of the following is the correct formula for the compound formed between magnesium and phosphate ions?

Accepted Answer

$$\mathrm{Mg_3$(PO_4$)_2}$$

Question 2

What is the correct name for the compound $$\mathrm{Fe_2$(SO_4$)_3}$$?

Accepted Answer

Iron(III) sulfate

Question 3

Which of the following compounds contains a polyatomic ion?

Accepted Answer

$$\mathrm{$$KNO_3$$}$$

Question 4

Calculate the formula mass of $$\mathrm{Ca(OH)_2} ($$calcium hydroxide). (Atomic masses: Ca = 40, O = 16, H = 1)

Accepted Answer

$$40 + (2 	imes 16) + (2 	imes 1) = 74$$

Question 5

Which of the following ions has a $$-2$$ charge?

Accepted Answer

$$\mathrm{SO_4$^{2-}}$$

Question 6

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

Accepted Answer

$$0.5$$ mol

Question 7

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

Accepted Answer

$$\mathrm{Al_2$(SO_4$)_3}$$

Question 8

What is the empirical formula for a compound containing $$40\%$$ carbon, $$6.7\%$$ hydrogen, and $$53.3\%$$ oxygen by mass?

Accepted Answer

$$\mathrm{CH_2O}$$

Question 9

Which of the following best describes the relationship between the mole, Avogadro's number, and mass?

Accepted Answer

One mole of any substance contains $$6.022 	imes 10$$^{23}$$ particles and has a mass equal to its molar mass in grams.

Question 10

What is the correct name for $$\mathrm{K_2Cr_2O_7}$$?

Accepted Answer

Potassium dichromate

Question 11

Which of the following compounds is an acid anion?

Accepted Answer

$$\mathrm{$$HSO_4$$^-}$$

Question 12

How many oxygen atoms are present in $$2.5$$ moles of $$\mathrm{H_2SO_4}$$?

Accepted Answer

$$2.5 	imes 4 	imes 6.022 	imes 10$$^{23}$$

Question 13

Which of the following is the correct formula for ammonium phosphate?

Accepted Answer

$$\mathrm{(NH_4$)_3PO_4}$$

Question 14

A compound contains $$27.3\%$$ carbon and $$72.7\%$$ oxygen by mass. What is its empirical formula?

Accepted Answer

$$\mathrm{CO_2$}$$

Question 15

Which of the following is the correct formula for the compound formed between calcium and nitrate ions?

Accepted Answer

$$\mathrm{Ca(NO_3$)_2}$$

Question 16

What is the molar mass of $$\mathrm{Na_2CO_3}$$? (Atomic masses: Na = 23, C = 12, O = 16)

Accepted Answer

$$2 	imes 23 + 12 + 3 	imes 16 = 106 g/$$mol

Question 17

Which of the following is the correct name for $$\mathrm{$$CuSO_4$$}$$?

Accepted Answer

Copper(II) sulfate

Question 18

A sample of $$\mathrm{C_2H_6O}$$ weighs $$46 g. $$How many moles are present? (Atomic masses: C = 12, H = 1, O = 16)

Accepted Answer

$$1$$ mol

Question 19

Which of the following is the correct formula for the compound formed between barium and sulfate ions?

Accepted Answer

$$\mathrm{$$BaSO_4$$}$$

Question 20

Which of the following best describes the Law of Conservation of Mass as applied to chemical reactions?

Accepted Answer

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

Writing and Predicting Chemical Formulas, Stoichiometry, and Nomenclature: Study Notes for Introductory Chemistry

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