General Chemistry 2 - Nonelectrolyte & Electrolyte Solutions

Questions and Answers

Which substance will cause the greatest boiling point elevation in a solution at a 1m concentration?

1m CaCl2

1m C6H12O6

1m AlCl3 (correct)

1m NaCl

What is the primary factor affecting colligative properties of solutions?

Concentration of solute particles (correct)

Molar mass of the solute

Identity of the solute

Type of solvent used

Which of the following correctly classifies NaCl and C6H12O6 in terms of their impact on colligative properties?

NaCl is a strong electrolyte; C6H12O6 is a strong electrolyte

Both are non-electrolytes

NaCl is a strong electrolyte; C6H12O6 is a non-electrolyte (correct)

NaCl is a non-electrolyte; C6H12O6 is a strong electrolyte

How do ionic compounds like CaCl2 affect the number of solute particles in a solution compared to molecular compounds?

They increase the number of solute particles Signup and view all the answers

If 1m solutions of NaCl and C6H12O6 are compared, which property will be more affected by NaCl's dissociation?

All of the above Signup and view all the answers

Which of the following statements about colligative properties is true?

They depend on the total number of solute particles in solution Signup and view all the answers

Which pair of substances, when dissolved in water, will exhibit the least freezing point depression at the same molality?

1m C6H12O6 and 1m NaCl Signup and view all the answers

In assessing the effects of solutes on colligative properties, how are electrolytes different from non-electrolytes?

Electrolytes dissociate into ions, increasing particle count Signup and view all the answers

What mainly determines the colligative properties of a solution?

The total concentration of solute particles Signup and view all the answers

What is the formula for calculating molality?

m = mole solute / kg solvent Signup and view all the answers

Which statement correctly describes why adding salt to boiling water increases its temperature?

Salt increases the number of particles, requiring more energy to reach the boiling point. Signup and view all the answers

How much does the boiling point of water increase when 5 g of C12H22O11 is added?

0.041 °C Signup and view all the answers

What happens to the melting point of water when salts are added?

The melting point decreases, allowing water to freeze at lower temperatures. Signup and view all the answers

What is the boiling point of the solution when 85.0 g of Sodium acetate is dissolved in 356 mL of water?

102.2124 °C Signup and view all the answers

What type of solution does NOT dissociate into ions when dissolved in a solvent?

Nonelectrolyte solutions Signup and view all the answers

What is the effect of colligative properties on boiling point elevation?

It increases the boiling point based solely on the number of solute particles. Signup and view all the answers

What is the change in temperature (ΔTb) when 85.0 g of Sodium acetate is added to the solution?

2.124 °C Signup and view all the answers

What condition is required for freezing point depression to occur?

The solvent must be pure. Signup and view all the answers

In the context of nonelectrolyte and electrolyte solutions, the presence of more solute particles generally leads to which result?

Increased boiling point and decreased freezing point Signup and view all the answers

What relationship exists between molality and the freezing point depression?

They are directly proportional. Signup and view all the answers

Why do ice vendors add salt to the ice used in ice cream containers?

To lower the freezing point of the ice, keeping the temperature low. Signup and view all the answers

If 100 g of NaCl were added to 1 kg of water, what effect would it have on the boiling point of water?

It would slightly increase the boiling point. Signup and view all the answers

The calculation of molar mass from colligative properties is primarily affected by which factor?

The boiling point elevation and freezing point depression values Signup and view all the answers

What is the boiling point constant (Kb) for water used in these calculations?

0.512 °C/m Signup and view all the answers

What is the change in boiling point (ΔTb) when 15.0 g of an organic compound is dissolved in carbon tetrachloride resulting in a boiling point of 84.36°C?

7.64°C Signup and view all the answers

Using the boiling point elevation equation, if Kb for carbon tetrachloride is 5.02°C/m and the observed boiling point elevation is 7.64°C, what is the molality of the solution?

1.52 m Signup and view all the answers

How many moles of solute are present when 220 g of carbon tetrachloride is dissolved with a molality of 1.522 mol/kg?

0.3348 mol Signup and view all the answers

What is the molar mass of a solute if 15.00 g of it corresponds to 0.3348 moles?

44.80 g/mol Signup and view all the answers

How many grams of Pyrazine (C4H4N2) are needed to lower the freezing point of carbon tetrachloride by 5.6°C?

29.633 g Signup and view all the answers

Given a molar mass of 80.0896 g/mol for Pyrazine, what is the total mass if 0.37 mol is to be dissolved?

29.633 g Signup and view all the answers

If the freezing point depression constant (Kf) for carbon tetrachloride is 30.0°C/m, what is the relationship between freezing point depression and molality?

Δt = Kf x m Signup and view all the answers

What substance is being dissolved in carbon tetrachloride in Sample Problem 2 to achieve freezing point depression?

Pyrazine Signup and view all the answers

What is the boiling point of the solution when 0.20 grams of eugenol is dissolved in 12.0 grams of benzene?

80.70 °C Signup and view all the answers

How does the freezing point of a solution containing benzoic acid compare to that of pure benzene?

It will be lower than 5.50 °C Signup and view all the answers

What formula is used to calculate the boiling point elevation of a solution?

ΔT = i * Kb * m Signup and view all the answers

What is the molal freezing point depression constant (Kf) of water used for calculations?

1.86 °C/m Signup and view all the answers

In the freezing point depression calculations, which component is affected by the addition of the solute?

The freezing point of the solvent Signup and view all the answers

When calculating the molecular weight of a solute using freezing point depression, what information is required?

Mass of solute and Kf of solvent Signup and view all the answers

What would be the effect on the boiling point of a solution when more solute is dissolved?

The boiling point increases Signup and view all the answers

If 12g of glucose is dissolved in 200g of water, how much does the boiling point increase?

0.5120 °C Signup and view all the answers

Study Notes

Solutions Overview

Solutions consist of solute (substance dissolved) and solvent (substance doing the dissolving).
Properties of solutions, including colligative properties, depend on the amount of solute present.
Colligative properties are influenced by the number of solute particles, not their identity.

Colligative Properties

Colligative properties include boiling point elevation and freezing point depression.
These properties demonstrate how adding a solute (like salt) changes boiling and freezing points of solvents.
Example: Salt added to water raises its boiling point and lowers its freezing point.

Electrolyte vs. Nonelectrolyte

Electrolytes (e.g., NaCl) dissociate into ions, increasing the number of particles in solution.
Nonelectrolytes (e.g., sucrose) do not dissociate, resulting in fewer particles in the solution.
The effect on boiling and freezing points is greater with electrolytes due to increased particle count.

Calculating Colligative Properties

Molality (m) is calculated as the number of moles of solute per kilogram of solvent.
- Formula: Molality = moles of solute / kg of solvent
Boiling point elevation (ΔTb) can be calculated using ΔTb = Kb x m.
Freezing point depression and its relationship to the colligative properties are similar to boiling point calculations.

Example Calculations

Boiling Point Elevation Example:
- For a solution with 5 g of sucrose in 180 g of water:
  - Molality = 0.081 m, Kb for water = 0.512 °C/m
  - ΔTb = Kb x m = 0.041 °C, resulting in a new boiling point of 100.041 °C.
Freezing Point Depression Example:
- Adding a non-volatile solute lowers the vapor pressure and the freezing point.
- For a 15 g compound in 220 g carbon tetrachloride:
  - ΔTb = 7.64 °C, leading to a molar mass of 44.80 g/mol after calculations.

Exercise Problems

Practice involves solving for boiling points and freezing points with given constants and solute quantities.
Activities include calculating specific scenarios such as the effects of different solutes on boiling and freezing points.

Assessments

Students are tasked with determining molecular weights, boiling point elevations, and freezing point depressions through problem-solving scenarios.
These problems reinforce understanding of colligative properties and their dependence on solute concentrations.

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Description

This quiz focuses on the concepts of nonelectrolyte and electrolyte solutions covered in General Chemistry 2 for grades 11 and 12. It is based on Module 5 from Quarter 3, helping students to understand the distinctions and applications of these types of solutions. Test your knowledge and prepare for your examinations!