Question 1

Which of the following best describes a compound?

Accepted Answer

A substance formed when two or more different elements chemically combine in fixed proportions.

Question 2

Which equation correctly represents the reaction between magnesium and hydrochloric acid?

Accepted Answer

$$\mathrm{Mg} + 2\mathrm{HCl} \rightarrow \mathrm{MgCl}_2 + \mathrm{H}_2$$

Question 3

A student bubbles carbon dioxide through limewater. What observation and chemical equation best describe this test?

Accepted Answer

The limewater turns milky; $$\mathrm{Ca(OH)_2(aq)} + \mathrm{CO_2$(g)} \rightarrow \mathrm{$$CaCO_3$$(s)} + \mathrm{H_2O(l)}$$

Question 4

Which of the following is the correct ionic equation for the reaction between hydrochloric acid and sodium hydroxide?

Accepted Answer

$$\mathrm{H^+(aq)} + \mathrm{OH^-(aq)} \rightarrow \mathrm{H_2O(l)}$$

Question 5

A sample contains $$1.25\ \mathrm{g} of $$water. How many molecules of water are present? ($$M_r of$$ $$\mathrm{H_2O} = 18.0)$$

Accepted Answer

$$4.18 	imes 10$$^{22}$$

Question 6

Which of the following best describes a displacement reaction?

Accepted Answer

A reaction in which one element replaces another, less reactive element in a compound.

Question 7

Calculate the empirical formula for a compound containing 34.3% Na, 17.9% C, and 47.8% O by mass. (Ar: Na = 23.0, C = 12.0, O = 16.0)

Accepted Answer

$$\mathrm{Na_2CO_3}$$

Question 8

Which of the following is the correct balanced equation for the reaction of zinc with hydrochloric acid?

Accepted Answer

$$\mathrm{Zn} + 2\mathrm{HCl} \rightarrow \mathrm{ZnCl}_2 + \mathrm{H}_2$$

Question 9

Which of the following is the correct formula for calculating the number of moles from mass and molar mass?

Accepted Answer

$$n = \frac{m}{M}$$

Question 10

A reaction produces $$5.0\ \mathrm{g} of $$product, but the theoretical yield is $$6.0\ \mathrm{g}. $$What is the percentage yield?

Accepted Answer

$$83.3\%$$

Question 11

Which of the following statements about atom economy is correct?

Accepted Answer

Addition reactions have 100% atom economy.

Question 12

What is the molar volume of a gas at room temperature and pressure (r.t.p.)?

Accepted Answer

$$24\ \mathrm{dm}^3$$

Question 13

Which of the following is the correct ionic equation for the test for a sulfate ion?

Accepted Answer

$$\mathrm{Ba$$^{2+}$$(aq)} + \mathrm{SO_4$^{2-}(aq)} \rightarrow \mathrm{$$BaSO_4$$(s)}$$

Question 14

A gas occupies $$600\ \mathrm{cm}^3 at r.t.p. $$How many moles of the gas are present? (Molar volume at r.t.p. = $$24,000\ \mathrm{cm}^3)$$

Accepted Answer

$$0.025$$ moles

Question 15

Which of the following is the correct empirical formula for a compound with $$3.43\ \mathrm{g} of Cu $$and $$0.85\ \mathrm{g} of O$$? (Ar: Cu = 63.5, O = 16.0)

Accepted Answer

$$\mathrm{CuO}$$

Question 16

Which of the following is the correct balanced equation for the reaction of lead nitrate with potassium iodide?

Accepted Answer

$$\mathrm{Pb(NO_3$)_2(aq)} + 2\mathrm{KI(aq)} \rightarrow \mathrm{$$PbI_2$$(s)} + 2\mathrm{$$KNO_3$$(aq)}$$

Question 17

Which of the following is the correct formula for the ideal gas equation?

Accepted Answer

$$pV = nRT$$

Question 18

Which of the following is a correct conversion from $$\mathrm{cm}^3 to$$ $$\mathrm{m}^3$$?

Accepted Answer

Divide by $$10^6$$

Formulae, Equations, and Amount of Substances: Introductory Chemistry Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard