Q: A chemical reaction has a theoretical yield of 10.0 g and an actual yield of 8.0 g. What is the percent yield?

$$\frac{8.0}{10.0} \times 100\% = 80\%$$

Question 1

Which of the following best describes a heterogeneous mixture?

Accepted Answer

A mixture in which the components are not uniformly distributed, such as sand in water.

Question 2

Which statement correctly distinguishes between physical and chemical changes?

Accepted Answer

Physical changes do not alter the chemical composition of a substance, while chemical changes do.

Question 3

A student measures the mass of a sample as 12.30 g and its volume as 4.10 mL. What is the density of the sample?

Accepted Answer

$$\frac{12.30}{4.10} = 3.00\ \mathrm{g/mL}$$

Question 4

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

Accepted Answer

Reactivity with oxygen

Question 5

Which scientist is credited with the discovery of the electron using the cathode ray tube experiment?

Accepted Answer

J.J. Thomson

Question 6

What is the empirical formula for a compound containing 40.0% carbon, 6.7% hydrogen, and 53.3% oxygen by mass?

Accepted Answer

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

Question 7

Which of the following best describes the difference between an ionic and a covalent compound?

Accepted Answer

Ionic compounds are formed by transferring electrons, while covalent compounds are formed by sharing electrons.

Question 8

A chemical reaction has a theoretical yield of 10.0 g and an actual yield of 8.0 g. What is the percent yield?

Accepted Answer

$$\frac{8.0}{10.0} 	imes 100\% = 80\%$$

Question 9

Which of the following is a correct balanced chemical equation for the reaction of sodium with chlorine to form sodium chloride?

Accepted Answer

$$2\mathrm{Na} + \mathrm{Cl}_2 \rightarrow 2\mathrm{NaCl}$$

Question 10

Which statement about the periodic table is correct?

Accepted Answer

Elements in the same group have the same number of valence electrons.

Question 11

Which of the following is the correct electron configuration for a neutral oxygen atom?

Accepted Answer

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

Question 12

Which of the following best explains why water is a polar molecule?

Accepted Answer

Water has a bent molecular shape and a difference in electronegativity between oxygen and hydrogen.

Question 13

A solution is prepared by dissolving 5.00 g of NaCl in enough water to make 250 mL of solution. What is the molarity of the solution? (Molar mass of NaCl = 58.44 g/mol)

Accepted Answer

$$\frac{5.00\ \mathrm{g}}{58.44\ \mathrm{g/mol}} = 0.0856\ \mathrm{mol}$$; $$\frac{0.0856\ \mathrm{mol}}{0.250\ \mathrm{L}} = 0.342\ \mathrm{M}$$

Question 14

Which of the following is a double displacement reaction?

Accepted Answer

$$\mathrm{AgNO}_3 + \mathrm{NaCl} \rightarrow \mathrm{AgCl} + \mathrm{NaNO}_3$$

Question 15

Which of the following best describes the octet rule?

Accepted Answer

Atoms tend to gain, lose, or share electrons to achieve eight electrons in their outermost shell.

Question 16

Which of the following is the correct formula for calculating the molar mass of glucose ($$\mathrm{C}_6\mathrm{H}_{12}\mathrm{O}_6$$)?

Accepted Answer

$$6 	imes \mathrm{M}_\mathrm{C} + 12 	imes \mathrm{M}_\mathrm{H} + 6 	imes \mathrm{M}_\mathrm{O}$$

Question 17

Which of the following statements about acids and bases is correct?

Accepted Answer

Acids increase the concentration of hydrogen ions ($$\mathrm{H}^+) in $$solution.

Question 18

Which of the following is the correct formula for calculating the energy of a photon?

Accepted Answer

$$E = h 
u$$

Question 19

Which of the following best describes a limiting reactant in a chemical reaction?

Accepted Answer

The reactant that determines the amount of product formed.

Question 20

Which of the following is the correct formula for calculating molarity?

Accepted Answer

$$M = \frac{	ext{moles of solute}}{	ext{liters of solution}}$$

CHEM 1025 Final Exam Review Topics (Ch 2-10 & 13): Structured Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard