Question 1

Which of the following statements about isotopes is correct?

Accepted Answer

Isotopes of an element have the same number of protons but different numbers of neutrons.

Question 2

A student measures the mass of a metal as 45.42 g and the volume as 5.10 mL. What is the density of the metal?

Accepted Answer

$$8.91\,\mathrm{g/cm^3$}$$

Question 3

Which of the following is the correct empirical formula for a compound containing 10.15 g P and 34.85 g Cl?

Accepted Answer

$$\mathrm{$$PCl_3$$}$$

Question 4

Which of the following is NOT a physical change?

Accepted Answer

Burning gasoline in a car engine

Question 5

A sample contains $$2.50 	imes 10$$^{24}$$ atoms of aluminum. How many moles of aluminum are present?

Accepted Answer

$$4.15$$ mol

Question 6

Which of the following pairs are isotopes of the same element?

Accepted Answer

$$^{12}\mathrm{C}$$ and $$^{13}\mathrm{C}$$

Question 7

Which of the following statements about atomic structure is true?

Accepted Answer

A neutral atom contains the same number of protons and electrons.

Question 8

What is the molar mass of $$\mathrm{Ca_3$(PO_4$)_2}$$?

Accepted Answer

$$310.17\,\mathrm{g/mol}$$

Question 9

Which of the following is a heterogeneous mixture?

Accepted Answer

A mixture of sand and water

Question 10

Which of the following is the correct balanced equation for the reaction of aluminum with aqueous ammonium phosphate to form solid aluminum phosphate and aqueous ammonium chloride?

Accepted Answer

$$\mathrm{$$AlCl_3$$(aq) + (NH_4$)_3PO_4(aq) \rightarrow $$AlPO_4$$(s) + 3 NH_4Cl(aq)}$$

Question 11

Which of the following is the correct empirical formula for glucose ($$\mathrm{C_6H_{12}O_6$}$$)?

Accepted Answer

$$\mathrm{CH_2O}$$

Question 12

A compound contains 40.0% carbon, 6.7% hydrogen, and 53.3% oxygen by mass. What is its empirical formula?

Accepted Answer

$$\mathrm{CH_2O}$$

Question 13

Which of the following is a chemical property?

Accepted Answer

Iron rusts when exposed to oxygen.

Question 14

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

Accepted Answer

$$\mathrm{Ca_3$(PO_4$)_2}$$

Question 15

Which of the following statements about precision and accuracy is correct?

Accepted Answer

Precision refers to how close repeated measurements are to each other.

Question 16

Which of the following compounds is ionic?

Accepted Answer

$$\mathrm{KCl}$$

Question 17

Which of the following is the correct molar mass for $$\mathrm{Li_3PO_4}$$?

Accepted Answer

$$115.79\,\mathrm{g/mol}$$

Question 18

Which of the following elements will most likely form ionic cations in compounds?

Accepted Answer

Calcium

Question 19

A student mixes 50.0 g of sulfur and 105.0 g of fluorine to react completely to form sulfur hexafluoride ($$\mathrm{SF_6$}). $$What mass of excess reactant remains after the reaction?

Accepted Answer

$$20.5\,\mathrm{g}$$

General Chemistry I: Study Guide and Key Concepts (Chapters 1–4)

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