Question 1

Which of the following statements best describes an isotope?

Accepted Answer

Atoms of the same element with the same number of protons but different numbers of neutrons.

Question 2

Which of the following equations correctly represents the reaction between hydrochloric acid and sodium hydroxide, including state symbols?

Accepted Answer

$$\mathrm{HCl}(aq) + \mathrm{NaOH}(aq) \rightarrow \mathrm{NaCl}(aq) + \mathrm{H_2O}(l)$$

Question 3

A student mixes aqueous solutions of barium chloride and sodium sulfate. What observation and chemical principle explain the result?

Accepted Answer

A white precipitate forms due to the formation of insoluble barium sulfate.

Question 4

Which of the following best explains why ionic compounds conduct electricity when molten but not when solid?

Accepted Answer

Ions are free to move and carry charge only in the molten state.

Question 5

Calculate the number of moles in 44 grams of $$\mathrm{CO_2$}$$ ($$M_r = 44).$$

Accepted Answer

$$1$$ mole

Question 6

Which of the following is the correct electronic configuration for a calcium atom ($$Z=20$$)?

Accepted Answer

$$1s^2$$\ $$2s^2$$\ $$2p^6$$\ $$3s^2$$\ $$3p^6$$\ $$4s^2$$

Question 7

Which of the following best describes the trend in atomic radius across a period in the periodic table?

Accepted Answer

Atomic radius decreases due to increased nuclear charge.

Question 8

Which of the following is a correct statement about the bond in $$\mathrm{HCl}$$?

Accepted Answer

It is a polar covalent bond with Cl being partially negative.

Question 9

Which of the following is the empirical formula for hexane ($$\mathrm{C_6H_{14}}$$)?

Accepted Answer

$$\mathrm{C_3H_7}$$

Question 10

Which of the following best explains why graphite conducts electricity but diamond does not?

Accepted Answer

Graphite has delocalized electrons, while diamond does not.

Question 11

A sample contains $$3.01 	imes 10$$^{23}$$ molecules of $$\mathrm{$$CO_2$$}$$. How many moles of $$\mathrm{$$CO_2$$}$$ are present?

Accepted Answer

$$0.5$$ moles

Question 12

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

Accepted Answer

$$\mathrm{H^+} + \mathrm{OH^-} \rightarrow \mathrm{H_2O}$$

Question 13

Which of the following is a correct statement about the reaction of magnesium with hydrochloric acid?

Accepted Answer

It is a displacement reaction producing magnesium chloride and hydrogen gas.

Question 14

Which of the following is the correct formula for the percentage yield of a reaction?

Accepted Answer

$$\frac{	ext{actual yield}}{	ext{theoretical yield}} 	imes 100$$

Question 15

Which of the following best describes the process of fractional distillation of crude oil?

Accepted Answer

Separation of hydrocarbons based on their boiling points.

Question 16

Which of the following is a correct statement about the addition reaction of ethene with bromine?

Accepted Answer

The solution decolorizes as a dibromoethane is formed.

Question 17

Which of the following is the correct order of stability for carbocations?

Accepted Answer

Primary \u003c Secondary \u003c Tertiary

Question 18

Which of the following best describes the difference between chain isomerism and position isomerism?

Accepted Answer

Chain isomers have different chain lengths; position isomers differ in the position of functional groups.

Question 19

Which of the following is a property of giant covalent lattices such as diamond?

Accepted Answer

Very high melting point due to strong covalent bonds.

Comprehensive Study Notes: Foundations and Early Chapters of Organic Chemistry

Guida di studio - Domande di pratica