$$2.11 \times 10$$^{24}$$ atoms

Question 1

Which statement best describes the Law of Constant Composition?

Accepted Answer

A compound always contains the same elements in the same proportion by mass.

Question 2

How many total atoms are present in one formula unit of $$\mathrm{Mg_3$(PO_4$)_2}$$?

Accepted Answer

13

Question 3

Which of the following is an example of an ionic compound?

Accepted Answer

$$\mathrm{NaCl}$$

Question 4

What is the correct name for $$\mathrm{Fe_2O_3}$$?

Accepted Answer

Iron(III) oxide

Question 5

Which of the following is a molecular compound?

Accepted Answer

$$\mathrm{H_2O}$$

Question 6

Calculate the molar mass of $$\mathrm{C_6H_{12}O_6$} ($$glucose). Use the following atomic masses: C = 12.01 g/mol, H = 1.01 g/mol, O = 16.00 g/mol.

Accepted Answer

$$180.16\ \mathrm{g/mol}$$

Question 7

How many atoms are present in 3.5 moles of $$\mathrm{Mg}$$? (Avogadro's number $$= 6.022 	imes 10$$^{23}$$ atoms/mol)

Accepted Answer

$$2.11 	imes 10$$^{24}$$ atoms

Question 8

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

Accepted Answer

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

Question 9

What is the mass percent of oxygen in $$\mathrm{H_2O}$$? (H = 1.01 g/mol, O = 16.00 g/mol)

Accepted Answer

$$88.81\%$$

Question 10

Which type of reaction is represented by the following equation? $$\mathrm{2H_2 + O_2$ \rightarrow 2H_2O}$$

Accepted Answer

Synthesis reaction

Question 11

What is the correct name for $$\mathrm{Al_2$(SO_4$)_3}$$?

Accepted Answer

Aluminum sulfate

Question 12

Which of the following is evidence for a chemical reaction?

Accepted Answer

Formation of a precipitate

Question 13

Balance the following equation: $$\mathrm{C_2H_6 + O_2$ \rightarrow CO_2$ + H_2O}$$

Accepted Answer

$$2\mathrm{C_2H_6} + 7\mathrm{O_2$} \rightarrow 4\mathrm{CO_2$} + 6\mathrm{H_2O}$$

Question 14

Which of the following is an example of a precipitation reaction?

Accepted Answer

$$\mathrm{$$AgNO_3$$ + NaCl \rightarrow AgCl + $$NaNO_3$$}$$

Question 15

What is the molar mass of $$\mathrm{Ba_3$(PO_4$)_2}$$? (Ba = 137.33 g/mol, P = 30.97 g/mol, O = 16.00 g/mol)

Accepted Answer

$$601.89\ \mathrm{g/mol}$$

Question 16

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

Accepted Answer

$$\mathrm{$$CaCO_3$$}$$

Question 17

Which of the following is an example of an oxidation-reduction (redox) reaction?

Accepted Answer

$$\mathrm{Zn + $$CuSO_4$$ \rightarrow $$ZnSO_4$$ + Cu}$$

Question 18

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

Accepted Answer

Sulfuric acid

Question 19

Which compound contains only nonmetals?

Accepted Answer

$$\mathrm{Cl_2$}$$

Fundamental Concepts in Introduction to Chemistry: Composition, Nomenclature, Moles, and Chemical Reactions

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