Q: A sample contains 3.00 g of carbon-12. How many atoms of carbon-12 are present in the sample? (Atomic mass of C = 12.01 g/mol, Avogadro's number $$= 6.022 \times 10$$^{23}$$)

$$1.51 \times 10$$^{23}$$ atoms

Q: Which of the following is the correct formula for calculating the percent yield in a chemical reaction?

$$\text{Percent yield} = \dfrac{\text{Actual Yield}}{\text{Theoretical Yield}} \times 100$$

Q: Which of the following is the correct formula for calculating the atomic mass of an element with multiple isotopes?

$$\text{Atomic Mass} = \sum (\text{fraction of isotope n} \times \text{mass of isotope n})$$

Q: Which of the following is the correct relationship for molarity ($$M$$)?

$$M = \dfrac{\text{amount of solute (in mol)}}{\text{volume of solution (in L)}}$$

Question 1

Which of the following statements best describes a chemical change?

Accepted Answer

Atoms rearrange, transforming the original substances into different substances.

Question 2

A sample contains 3.00 g of carbon-12. How many atoms of carbon-12 are present in the sample? (Atomic mass of C = 12.01 g/mol, Avogadro's number $$= 6.022 	imes 10$$^{23}$$)

Accepted Answer

$$1.51 	imes 10$$^{23}$$ atoms

Question 3

Which of the following is the correct formula for calculating the percent yield in a chemical reaction?

Accepted Answer

$$	ext{Percent yield} = \dfrac{	ext{Actual Yield}}{	ext{Theoretical Yield}} 	imes 100$$

Question 4

A solution is prepared by diluting 50.0 mL of 2.00 M NaCl to a final volume of 200.0 mL. What is the final concentration of NaCl?

Accepted Answer

0.50 M

Question 5

Which of the following best describes a strong electrolyte?

Accepted Answer

A solute that completely dissociates in solution and strongly conducts electricity.

Question 6

Which of the following is the correct balanced net ionic equation for the reaction between $$\mathrm{KOH}(aq)$$ and $$\mathrm{Mg(NO_3$)_2}(aq)$$?

Accepted Answer

$$2\mathrm{OH}^-(aq) + \mathrm{Mg}^{2+}(aq) \rightarrow \mathrm{Mg(OH)_2}(s)$$

Question 7

A gas sample has a volume of 2.50 L at 1.00 atm and 300 K. What will its volume be at 2.00 atm and 300 K? (Assume ideal gas behavior.)

Accepted Answer

1.25 L

Question 8

Which of the following is the correct expression for the ideal gas law?

Accepted Answer

$$PV = nRT$$

Question 9

Which statement about atomic structure is correct?

Accepted Answer

Protons and neutrons have nearly identical masses.

Question 10

A compound contains 40.0% carbon, 6.7% hydrogen, and 53.3% oxygen by mass. What is the empirical formula of the compound?

Accepted Answer

$$\mathrm{CH_2O}$$

Question 11

Which of the following is true about resonance structures?

Accepted Answer

Resonance structures differ only by the movement of electrons.

Question 12

Which of the following is the correct formula for calculating the atomic mass of an element with multiple isotopes?

Accepted Answer

$$	ext{Atomic Mass} = \sum (	ext{fraction of isotope n} 	imes 	ext{mass of isotope n})$$

Question 13

Which of the following statements about the periodic table is correct?

Accepted Answer

Elements in the same group have similar chemical properties.

Question 14

Which of the following is the correct relationship for molarity ($$M$$)?

Accepted Answer

$$M = \dfrac{	ext{amount of solute (in mol)}}{	ext{volume of solution (in L)}}$$

Question 15

Which of the following is a correct statement about redox reactions?

Accepted Answer

The oxidizing agent is reduced and the reducing agent is oxidized.

Question 16

A balloon contains 0.50 mol of helium gas at 1.00 atm and 273 K. What is the volume of the balloon? ($$R = 0.08206 \dfrac{L \cdot atm}{mol \cdot K})$$

Accepted Answer

11.0 L

Question 17

Which of the following is true about sigma ($$\sigma) $$and pi ($$\pi) $$bonds?

Accepted Answer

A $$\sigma$$ bond results from orbitals pointing along the axis connecting two nuclei.

Question 18

Which of the following is the correct formula for calculating the change in enthalpy ($$\Delta H) $$using bond energies?

Accepted Answer

$$\Delta H = \sum 	ext{(bond energies of bonds broken)} - \sum 	ext{(bond energies of bonds formed)}$$

Question 19

Which of the following statements about molecular geometry is correct?

Accepted Answer

Molecular geometry considers only the arrangement of atoms (bonds), not lone pairs.

General Chemistry I Final Exam Review: Key Concepts and Formulas

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