Mod 10

Question 1

What is the definition of solute and solvent?

Answer 1

Solute is the substance in lesser quantity; solvent is in greater quantity.

Question 2

What distinguishes strong electrolytes from weak electrolytes?

Answer 2

Strong electrolytes fully dissociate in water, while weak electrolytes only partially dissociate.

Question 3

Name three examples of strong electrolytes.

Answer 3

• NaCl
• CaBr₂
• HCl

Question 4

What is the definition of solubility?

Answer 4

Solubility is the amount of solute that can dissolve in a given amount of solvent at a specified temperature.

Question 5

How does temperature affect the solubility of solids and gases?

Answer 5

For solids, solubility increases with temperature; for gases, solubility decreases with temperature.

Question 6

What are the three types of percent concentrations?

Answer 6

• mass/mass (m/m)
• mass/volume (m/v)
• volume/volume (v/v)

Question 7

How do you calculate molarity (M)?

Answer 7

Molarity (M) = moles of solute per liter of solution.

Question 8

What is the relationship in the dilution formula?

Answer 8

M₁V₁ = M₂V₂, where moles of solute remain constant.

Question 9

What are colligative properties?

Answer 9

Properties that depend on the number of solute particles in a solution, such as freezing point depression and boiling point elevation.

Question 10

Define isotonic, hypotonic, and hypertonic solutions.

Answer 10

• Isotonic: equal osmotic pressure
• Hypotonic: lower osmotic pressure, may cause hemolysis
• Hypertonic: higher osmotic pressure, may cause crenation

Question 11

What is the formula for calculating freezing point depression?

Answer 11

ΔTf = i·Kf·m, where Kf is the freezing point depression constant.

Question 12

What does the kinetic molecular theory state about gas particles?

Answer 12

Gas particles move randomly at high speeds and are far apart, making their volume negligible.

Question 13

What is Boyle’s Law?

Answer 13

At constant temperature and amount of gas, pressure is inversely proportional to volume (P₁V₁ = P₂V₂).

Question 14

What is Charles’s Law?

Answer 14

At constant pressure, volume is directly proportional to absolute temperature (V₁/T₁ = V₂/T₂).

Question 15

What does Gay-Lussac’s Law describe?

Answer 15

The pressure of a gas is directly proportional to its absolute temperature at constant volume (P₁/T₁ = P₂/T₂).

Question 16

What is the combined gas law?

Answer 16

P₁V₁/T₁ = P₂V₂/T₂, relating pressure, volume, and temperature when the amount of gas is constant.

Question 17

What is the ideal gas law equation?

Answer 17

PV = nRT, where R is the ideal gas constant.

Question 18

What does Dalton’s law of partial pressures state?

Answer 18

The total pressure of a gas mixture equals the sum of the partial pressures of each individual gas (Pₜ = ΣPᵢ).

Question 19

Fill in the blank: The solubility of gases ______ with increasing temperature.

Answer 19

decreases

Question 20

True or False: An unsaturated solution contains less solute than can be dissolved at a given temperature.

Answer 20

True

Question 21

What is the molar volume of a gas at standard temperature and pressure (STP)?

Answer 21

22.4 L/mol

Question 22

What is the effect of temperature on the solubility of solids?

Answer 22

Solubility increases with temperature.

Question 23

What is the dissociation of CaCl₂ in water?

Answer 23

CaCl₂ → Ca²⁺ + 2 Cl⁻

Question 24

What are the units for pressure in gas laws?

Answer 24

atm, mmHg, kPa

Question 25

What happens to aerosol cans when heated?

Answer 25

They may burst due to increased pressure.

Question 26

What is the effect of a hypotonic solution on red blood cells?

Answer 26

It can cause hemolysis.

Question 27

What is the relationship described by Boyle’s Law regarding pressure and volume?

Answer 27

Pressure ↓ ⇒ Volume ↑; Pressure ↑ ⇒ Volume ↓ ## Footnote Boyle’s Law states that for a given mass of gas at constant temperature, the volume of the gas is inversely proportional to its pressure.

Question 28

What is the new volume of a helium balloon that starts at 2.50 L, 25 °C, and 1.02 atm, and ascends to 650 mmHg and –15 °C?

Answer 28

3.1 L ## Footnote This calculation involves using the Combined Gas Law.

Question 29

How much NH₃ is formed from 12.0 L of N₂ reacting with excess H₂ at 348 K and 1.20 atm?

Answer 29

9.0 g NH₃ ## Footnote This is an application of Ideal Gas Stoichiometry.

Question 30

What is the formula to calculate the total pressure (Pₜ) when dealing with a mixture of gases?

Answer 30

Pₜ = P_He + P_N₂ + P_Ne ## Footnote This formula is used to find the total pressure in a gas mixture.

Question 31

What is the dry pressure of H₂ when 250 mL of wet H₂ is collected at 24 °C with a total pressure of 755 mmHg, given the vapor pressure of water is 22 mmHg?

Answer 31

733 mmHg ## Footnote The dry pressure is calculated by subtracting the vapor pressure of water from the total pressure.

Question 32

What is the number of moles of H₂ calculated from a dry H₂ pressure of 733 mmHg?

Answer 32

0.0099 mol ## Footnote This calculation requires the use of the Ideal Gas Law.

Question 33

Complete the statement: Over water requires subtracting _______.

Answer 33

vapor pressure ## Footnote This is important for accurate pressure calculations in gas mixtures.

Question 34

In the context of gas laws, what does 'Pₜ' represent?

Answer 34

Total pressure ## Footnote Pₜ is the sum of the partial pressures of all gases in a mixture.

Question 35

What was the pressure of helium in the worksheet tank example?

Answer 35

0.644 atm ## Footnote This is one of the components used to calculate the total pressure in the gas mixture.

Question 36

What is the ideal gas constant (R) value used in gas law calculations?

Answer 36

0.0821 L·atm/(K·mol) ## Footnote This value is commonly used in the Ideal Gas Law calculations.