Q: What is the correct formula for calculating mass percent of an element in a compound?

$$\text{Mass percent} = \frac{\text{(# of element) x (AW of element)}}{\text{FW of molecule}} \times 100\%$$

Q: A sample contains 2.0 g of NaCl (molar mass = 58.44 g/mol). How many moles of NaCl are present?

$$\text{Moles} = \frac{2.0}{58.44} = 0.034\ \text{mol}$$

Q: What is the wavelength (in nm) of light with a frequency of $$6.0 \times 10$$^{14}$$\ \text{s}^{-1}$$? (Speed of light $$c = 3.0 \times 10^8$\ \text{m/s})$$

$$\lambda = \frac{c}{\nu} = \frac{3.0 \times 10^8$}{6.0 \times 10$$^{14}$$} = 5.0 \times 10$$^{-7}$$\ \text{m} = 500\ \text{nm}$$

Q: What is the correct formula for the compound formed between aluminum and sulfate ions?

$$\text{Al}_2\left(\text{SO}_4\right)_3$$

Q: Which of the following is the correct net ionic equation for the reaction between NaCl(aq) and AgNO3(aq)?

$$\text{Ag}^+ (aq) + \text{Cl}^- (aq) \rightarrow \text{AgCl} (s)$$

Q: A gas occupies 2.0 L at 1.0 atm and 300 K. What volume will it occupy at 2.0 atm and 300 K? (Assume ideal gas behavior)

$$V_2$$ = \frac{$$P_1$$ $$V_1$$}{$$P_2$$} = \frac{1.0 \times 2.0}{2.0} = 1.0\ \text{L}$$

Question 1

Which of the following statements best describes the difference between a physical and a chemical change?

Accepted Answer

A chemical change results in the formation of new substances, while a physical change does not.

Question 2

What is the correct formula for calculating mass percent of an element in a compound?

Accepted Answer

$$	ext{Mass percent} = \frac{	ext{(# of element) x (AW of element)}}{	ext{FW of molecule}} 	imes 100\%$$

Question 3

A sample contains 2.0 g of NaCl (molar mass = 58.44 g/mol). How many moles of NaCl are present?

Accepted Answer

$$	ext{Moles} = \frac{2.0}{58.44} = 0.034\ 	ext{mol}$$

Question 4

Which of the following is the correct electron configuration for magnesium (Mg, atomic number 12)?

Accepted Answer

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

Question 5

Which of the following compounds is expected to be insoluble in water according to the solubility rules?

Accepted Answer

BaSO4

Question 6

What is the wavelength (in nm) of light with a frequency of $$6.0 	imes 10$$^{14}$$\ 	ext{s}^{-1}$$? (Speed of light $$c = 3.0 	imes 10^8$\ 	ext{m/s})$$

Accepted Answer

$$\lambda = \frac{c}{
u} = \frac{3.0 	imes 10^8$}{6.0 	imes 10$$^{14}$$} = 5.0 	imes 10$$^{-7}$$\ 	ext{m} = 500\ 	ext{nm}$$

Question 7

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

Accepted Answer

Elements in the same group have similar chemical properties.

Question 8

What is the correct formula for the compound formed between aluminum and sulfate ions?

Accepted Answer

$$	ext{Al}_2\left(	ext{SO}_4ight)_3$$

Question 9

Which of the following is the correct net ionic equation for the reaction between NaCl(aq) and AgNO3(aq)?

Accepted Answer

$$	ext{Ag}^+ (aq) + 	ext{Cl}^- (aq) ightarrow 	ext{AgCl} (s)$$

Question 10

Which prefix is used in naming binary compounds to indicate the presence of seven atoms?

Accepted Answer

hepta-

Question 11

Which of the following statements about the first law of thermodynamics is correct?

Accepted Answer

The total energy of the universe remains constant.

Question 12

A gas occupies 2.0 L at 1.0 atm and 300 K. What volume will it occupy at 2.0 atm and 300 K? (Assume ideal gas behavior)

Accepted Answer

$$V_2$$ = \frac{$$P_1$$ $$V_1$$}{$$P_2$$} = \frac{1.0 	imes 2.0}{2.0} = 1.0\ 	ext{L}$$

Question 13

Which quantum number determines the shape of an atomic orbital?

Accepted Answer

Angular momentum quantum number ($$l)$$

Question 14

Which of the following elements has the highest first ionization energy?

Accepted Answer

Neon (Ne)

Question 15

Which of the following molecules is expected to be nonpolar based on its molecular geometry?

Accepted Answer

CO2

Question 16

What is the hybridization of the central atom in methane (CH4)?

Accepted Answer

sp3

Question 17

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

Accepted Answer

A triple bond consists of one $$\sigma$$ bond and two $$\pi$$ bonds.

Question 18

Which of the following is an exception to the octet rule?

Accepted Answer

BF3

Question 19

Which of the following is the correct formula for calculating the enthalpy change of a reaction using enthalpies of formation?

Accepted Answer

$$\Delta H_{rxn} = \sum \Delta H_f$$^{\circ}$$ (	ext{products}) - \sum \Delta H_f$$^{\circ}$$ (	ext{reactants})$$

General Chemistry I: Comprehensive Final Exam Study Guide

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