Q: A student needs to convert $$5.00\ \mathrm{km} to$$ $$\mathrm{cm}. $$Which of the following is the correct answer?

$$5.00 \times 10^5$\ \mathrm{cm}$$

Question 1

Which of the following is an example of a chemical change?

Accepted Answer

Iron rusting when exposed to air

Question 2

A student measures the mass of a metal block as $$45.67\ \mathrm{g}$$ and its volume as $$16.2\ \mathrm{cm}^3. $$What is the density of the block, reported with the correct number of significant figures?

Accepted Answer

$$2.8\ \mathrm{g/cm}^3$$

Question 3

Which of the following statements best describes an extensive property?

Accepted Answer

It depends on the amount of substance present.

Question 4

Which of the following is the correct formula and charge for the permanganate ion?

Accepted Answer

$$\mathrm{MnO}_4^-$$

Question 5

A sample contains $$60\%$$ $$^{63}\mathrm{Cu} ($$atomic mass $$62.93\ \mathrm{u}) $$and $$40\%$$ $$^{65}\mathrm{Cu} ($$atomic mass $$64.93\ \mathrm{u}). $$What is the average atomic mass of copper in this sample?

Accepted Answer

$$63.33\ \mathrm{u}$$

Question 6

Which of the following best describes the difference between a homogeneous and a heterogeneous mixture?

Accepted Answer

A homogeneous mixture has a uniform composition throughout, while a heterogeneous mixture does not.

Question 7

What is the correct name for the compound $$\mathrm{Na}_2\mathrm{SO}_4$$?

Accepted Answer

Sodium sulfate

Question 8

Which of the following ions has a $$2+$$ charge and is found in Group 2A of the periodic table?

Accepted Answer

$$\mathrm{Ca}^{2+}$$

Question 9

A student needs to convert $$5.00\ \mathrm{km} to$$ $$\mathrm{cm}. $$Which of the following is the correct answer?

Accepted Answer

$$5.00 	imes 10^5$\ \mathrm{cm}$$

Question 10

Which of the following is the correct electron configuration for a neutral atom of magnesium ($$\mathrm{Mg}$$, atomic number 12)?

Accepted Answer

$$1s^2$$\ $$2s^2$$\ $$2p^6$$\ $$3s^2$$

Question 11

Which of the following compounds is an example of a molecular (covalent) compound?

Accepted Answer

$$\mathrm{CO}_2$$

Question 12

How many significant figures are in the measurement $$0.00450\ \mathrm{g}$$?

Accepted Answer

3

Question 13

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

Accepted Answer

$$\mathrm{(NH}_4)_2\mathrm{SO}_4$$

Question 14

A compound is found to contain $$40.0\%$$ carbon, $$6.7\%$$ hydrogen, and $$53.3\%$$ oxygen by mass. What is its empirical formula?

Accepted Answer

$$\mathrm{CH}_2\mathrm{O}$$

Question 15

Which of the following best describes the law of definite proportions?

Accepted Answer

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

Question 16

What is the correct name for $$\mathrm{Fe}_2\mathrm{O}_3$$?

Accepted Answer

Iron(III) oxide

Question 17

A reaction has a theoretical yield of $$10.0\ \mathrm{g}$$, but only $$7.5\ \mathrm{g} of $$product is actually obtained. What is the percent yield?

Accepted Answer

$$75\%$$

Question 18

Which of the following is the correct formula for the thiosulfate ion?

Accepted Answer

$$\mathrm{S}_2\mathrm{O}_3$$^{2-}$$

Question 19

Which of the following best describes the difference between an atom and an ion?

Accepted Answer

An ion has a net electrical charge due to the loss or gain of electrons, while an atom is neutral.

Question 20

A solution is prepared by dissolving $$5.00\ \mathrm{g} of $$NaCl in enough water to make $$250.0\ \mathrm{mL} of $$solution. What is the molarity of the solution? ($$\mathrm{Molar\ mass\ of\ NaCl} = 58.44\ \mathrm{g/mol})$$

Accepted Answer

$$0.342\ \mathrm{M}$$

General Chemistry I: Matter, Measurements, Atoms, and Chemical Formulas

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