Q: Calculate the number of molecules in 32.11 g of NH\_3. (Molar mass of NH\_3 = 17.03 g/mol, Avogadro's number = $$6.022 \times 10$$^{23}$$ mol$$^{-1}$$)

$$1.13 \times 10$$^{24}$$ molecules

Question 1

Which of the following best describes the type of intermolecular force present between molecules of ammonia (NH\_3)?

Accepted Answer

Hydrogen bonding

Question 2

Calculate the number of molecules in 32.11 g of NH\_3. (Molar mass of NH\_3 = 17.03 g/mol, Avogadro's number = $$6.022 	imes 10$$^{23}$$ mol$$^{-1}$$)

Accepted Answer

$$1.13 	imes 10$$^{24}$$ molecules

Question 3

Which of the following is the correct molar mass for Pb(NO\_3)\_2?

Accepted Answer

$$331.2 g/$$mol

Question 4

A balloon filled with air at 13°C has a volume of 3.0 L. If the temperature increases to 25°C and the pressure remains constant, what is the new volume of the balloon? (Use Charles' Law: $$\frac{V_1$}{T_1$} = \frac{V_2$}{T_2$})$$

Accepted Answer

$$3.27 L$$

Question 5

Which of the following best describes the type of attraction between NaCl molecules in the solid state?

Accepted Answer

Ionic bonding

Question 6

What is the molarity, $$M$$, of a solution that contains 8.45 g of KI in 0.250 L of solution? (Molar mass of KI = 166.0 g/mol)

Accepted Answer

$$0.204 M$$

Question 7

If 23.2 L of neon gas at 2.1 atm is compressed to 18.1 L at constant temperature, what is the new pressure? (Use Boyle's Law: $$P_1V_1 = P_2V_2)$$

Accepted Answer

$$2.70$$ atm

Question 8

Which of the following molecules would exhibit only London dispersion forces as the primary intermolecular force?

Accepted Answer

CH\_4

Question 9

Calculate the mass of KOH required to prepare 355 mL of 0.22 M KOH solution. (Molar mass of KOH = 56.11 g/mol)

Accepted Answer

$$4.37 g$$

Question 10

Which of the following statements about Avogadro's Law is correct?

Accepted Answer

At constant temperature and pressure, equal volumes of gases contain equal numbers of molecules.

Question 11

A sample of nitrogen gas occupies 0.600 mol at 3.00 atm and 30°C. What is the volume occupied by the gas? (Use $$PV = nRT$$, $$R = 0.0821 L$$·atm·K$$^{-1}$$·mol$$^{-1})$$

Accepted Answer

$$4.92 L$$

Question 12

Which of the following is NOT a requirement for hydrogen bonding?

Accepted Answer

Hydrogen bonded to Cl

Question 13

Which of the following is the correct value for Avogadro's number?

Accepted Answer

$$6.022 	imes 10$$^{23}$$

Question 14

Which of the following best explains why water (H\_2O) has a higher boiling point than methane (CH\_4)?

Accepted Answer

Water molecules have stronger hydrogen bonding than methane

Question 15

A chemical reaction produces water according to the equation: $$2H_2 + O_2$ \rightarrow 2H_2O. If 19.3 g of $$hydrogen is reacted, what mass of water will be formed? (Molar mass H\_2 = 2.02 g/mol, H\_2O = 18.02 g/mol)

Accepted Answer

$$172 g$$

Question 16

Which of the following is the correct formula for converting Celsius to Kelvin?

Accepted Answer

$$K = ^\circ C + 273.15$$

Question 17

Which of the following pairs of molecules will exhibit dipole-dipole interactions?

Accepted Answer

CO and CO

Question 18

Which of the following is the correct expression for density?

Accepted Answer

$$d = \frac{m}{V}$$

Question 19

At STP, what volume does 1 mole of any ideal gas occupy?

Accepted Answer

$$22.4 L$$

Question 20

Which of the following is true about London dispersion forces?

Accepted Answer

They are present in all molecules, but are the only force in nonpolar molecules.

General Chemistry: Mole Calculations, Solutions, Gas Laws, and Intermolecular Forces

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