The number of particles in one mole, $$6.022 \times 10$$^{23}$$

$$8 \times 6.022 \times 10$$^{23}$$

Question 1

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

Accepted Answer

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

Question 2

What is the correct name for the compound $$\mathrm{$$FeCl_3$$}$$?

Accepted Answer

Iron(III) chloride

Question 3

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

Accepted Answer

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

Question 4

Calculate the formula mass of $$\mathrm{Mg(OH)_2}$$ given the atomic masses: Mg = 24, O = 16, H = 1.

Accepted Answer

$$\mathrm{24 + 2(16 + 1) = 58\ g/mol}$$

Question 5

Which of the following compounds contains a polyatomic ion?

Accepted Answer

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

Question 6

How many moles are present in $$18$$ grams of water ($$\mathrm{H_2O}$$)? (H = 1, O = 16)

Accepted Answer

$$1$$ mole

Question 7

What is the correct formula for ammonium phosphate?

Accepted Answer

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

Question 8

Which of the following best describes Avogadro's number?

Accepted Answer

The number of particles in one mole, $$6.022 	imes 10$$^{23}$$

Question 9

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

Accepted Answer

$$0.5$$ moles

Question 10

Which of the following is the correct name for $$\mathrm{Na_2SO_4}$$?

Accepted Answer

Sodium sulfate

Question 11

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

Accepted Answer

$$\mathrm{CH_2O}$$

Question 12

Which of the following is the correct formula for calcium nitrate?

Accepted Answer

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

Question 13

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

Accepted Answer

$$8 	imes 6.022 	imes 10$$^{23}$$

Question 14

Which of the following is the correct formula for the compound formed between potassium and dichromate ions?

Accepted Answer

$$\mathrm{K_2Cr_2O_7}$$

Question 15

A $$10.0 g $$sample of $$\mathrm{NaCl}$$ contains how many moles? (Na = 23, Cl = 35.5)

Accepted Answer

$$0.171$$ moles

Question 16

Which of the following is the correct name for $$\mathrm{H_2SO_4}$$?

Accepted Answer

Sulfuric acid

Question 17

What is the oxidation number of chromium in $$\mathrm{K_2Cr_2O_7}$$?

Accepted Answer

$$+6$$

Question 18

Which of the following compounds is a hydrate?

Accepted Answer

$$\mathrm{$$CuSO_4$$ \cdot 5H_2O}$$

Question 19

Which of the following is the correct formula for iron(II) sulfate?

Accepted Answer

$$\mathrm{$$FeSO_4$$}$$

Question 20

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

Accepted Answer

$$\mathrm{CO_2$}$$

Writing and Predicting Chemical Formulas, Nomenclature, and Composition Stoichiometry

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