Question 1

Which of the following best describes a scientific hypothesis?

Accepted Answer

A tentative explanation for a set of observations that can be tested experimentally.

Question 2

A 5.77 g sample of calcium carbonate completely decomposes into calcium oxide and carbon dioxide when heated. If $$2.23\ \mathrm{g} of $$calcium oxide is produced, what mass of carbon dioxide must have been formed?

Accepted Answer

$$3.54\ \mathrm{g}$$

Question 3

Which of the following is a homogeneous mixture?

Accepted Answer

Salt water

Question 4

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

Accepted Answer

Precision refers to the reproducibility of measurements, while accuracy refers to how close a measurement is to the true value.

Question 5

How many significant figures are in the number $$0.007070 	imes 10^4$?

Accepted Answer

4

Question 6

Express $$0.000460 in $$scientific notation.

Accepted Answer

$$4.60 	imes 10$$^{-4}$$

Question 7

A sample of an element contains $$5.062 	imes 10$$^{21}$$ atoms and has a mass of 1.067$$\ \mathrm{g}$$. What is the element?

Accepted Answer

Silver ($$\mathrm{Ag})$$

Question 8

Which of the following pairs of compounds can be used to illustrate the law of multiple proportions?

Accepted Answer

NO and NO$$_2$$

Question 9

How many electrons does the ion $$^{35}_{17}\mathrm{Cl}^-$$ have?

Accepted Answer

18

Question 10

Which of the following statements is true concerning the two nuclides $$^{3}_{1}\mathrm{H}$$ and $$^{4}_{2}\mathrm{He}$$?

Accepted Answer

They have different chemical properties.

Question 11

Lithium has two naturally occurring isotopes, $$^6\mathrm{Li}$$ and $$^7\mathrm{Li}. $$The average atomic mass of lithium is $$6.941. $$Which statement about the relative abundance of each isotope is correct?

Accepted Answer

The abundance of $$^7\mathrm{Li} is $$greater than $$^6\mathrm{Li}.$$

Question 12

What is the empirical formula for a compound with $$64.3\%$$ carbon, $$7.2\%$$ hydrogen, and $$28.5\%$$ oxygen by mass?

Accepted Answer

$$\mathrm{C}_3\mathrm{H}_4\mathrm{O}$$

Question 13

A $$20.0\ \mathrm{g}$$ sample of $$\mathrm{C}_2\mathrm{H}_4$$ and $$60.0\ \mathrm{g} of$$ $$\mathrm{O}_2$$ react to form $$\mathrm{CO}_2$$ and $$\mathrm{H}_2\mathrm{O}. $$How many grams of water are formed? (Balanced equation: $$2\mathrm{C}_2\mathrm{H}_4 + 7\mathrm{O}_2 \rightarrow 4\mathrm{CO}_2 + 4\mathrm{H}_2\mathrm{O})$$

Accepted Answer

$$28.8\ \mathrm{g}$$

Question 14

If $$0.630\ \mathrm{kg} of $$copper(I) sulfide reacts with excess oxygen to produce $$0.190\ \mathrm{kg} of $$copper metal, what is the percent yield? (Balanced equation: $$\mathrm{Cu}_2\mathrm{S} + \mathrm{O}_2 \rightarrow 2\mathrm{Cu} + \mathrm{SO}_2)$$

Accepted Answer

$$37.8\%$$

Question 15

Which of the following statements about limiting reactants is correct?

Accepted Answer

The theoretical yield depends on the amount of limiting reactant.

Question 16

What is the molar mass of ammonium sulfate, $$(\mathrm{NH}_4)_2\mathrm{SO}_4$$?

Accepted Answer

$$132\ \mathrm{g/mol}$$

Question 17

Which of the following is the correct formula for iron(III) sulfide?

Accepted Answer

$$\mathrm{Fe}_2\mathrm{S}_3$$

Question 18

Which of the following best describes the type of chemical bond formed between sodium and chlorine in sodium chloride?

Accepted Answer

Ionic bond

Question 19

What is the percentage by mass of hydrogen in ammonium phosphate, $$(\mathrm{NH}_4)_3\mathrm{PO}_4$$?

Accepted Answer

$$8.11\%$$

Question 20

Which of the following is the empirical formula for a molecule with the formula $$\mathrm{C}_2\mathrm{O}_2\mathrm{H}_4$$?

Accepted Answer

$$\mathrm{CHO}$$

General Chemistry Exam Study Guide: Fundamental Concepts, Calculations, and Problem Solving

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