Questions and Answers
What is the molarity of a solution containing 5 g of NaOH in 450 mL?
How is molality defined?
Why is molarity considered a function of temperature?
What mass of KCl corresponds to a 1.00 mol kg solution?
Signup and view all the answers
What is the molality of 2.5 g of ethanoic acid in 75 g of benzene?
Signup and view all the answers
How does total vapor pressure over a solution relate to the mole fraction of one component?
Signup and view all the answers
What happens to the total vapor pressure over the solution as the mole fraction of component 2 increases?
Signup and view all the answers
Which statement correctly describes the graphical representation of vapor pressure vs. mole fraction?
Signup and view all the answers
What could be concluded if the total vapor pressure has a maximum value of $p_2$?
Signup and view all the answers
In the context of the solution described, what is indicated by a minimum value of total vapor pressure at $p_1$?
Signup and view all the answers
What does Dalton conclude about the concentration of dissolved gas in a solution?
Signup and view all the answers
In the equation p = KH x, what does KH represent?
Signup and view all the answers
What relationship does Henry's law illustrate?
Signup and view all the answers
Why do different gases have different KH values at the same temperature?
Signup and view all the answers
If you were to plot partial pressure versus mole fraction of a gas in solution, what type of graph would you expect?
Signup and view all the answers
What causes the decrease in the vapour pressure of a solution compared to that of the pure solvent?
Signup and view all the answers
How does the addition of non-volatile solutes, like sucrose or urea, affect the vapour pressure of water?
Signup and view all the answers
According to Raoult's law, the partial vapour pressure of each component in a binary solution is proportional to what?
Signup and view all the answers
What is the relationship between the amount of non-volatile solute and the decrease in vapour pressure?
Signup and view all the answers
Which statement accurately describes the effect of solute on the solvent's vapour pressure?
Signup and view all the answers
What does it indicate when the enthalpy of mixing of two pure components is zero?
Signup and view all the answers
What characterizes a solution that behaves ideally?
Signup and view all the answers
Which of the following pairs of substances is likely to form an ideal solution?
Signup and view all the answers
What is the result of a non-ideal solution exhibiting positive deviation from Raoult’s law?
Signup and view all the answers
In terms of volume, what happens when two ideal components are mixed?
Signup and view all the answers
Which condition defines a non-ideal solution?
Signup and view all the answers
What kind of deviation occurs when the vapor pressure of a solution is lower than predicted?
Signup and view all the answers
Which of the following statements is true regarding ideal solutions?
Signup and view all the answers
Study Notes
Molarity Calculation
- Molarity (M) is calculated as moles of solute per liter of solution.
- For NaOH, with a mass of 5 g, the number of moles is 0.125 mol using the molar mass of 40 g/mol.
- The volume of the solution is converted from 450 mL to 0.450 L.
- Molarity of the NaOH solution is calculated as 0.125 mol × 1000 mL/L ÷ 450 mL, yielding 0.278 M.
Molality Definition
- Molality (m) is defined as the number of moles of solute per kilogram of solvent.
- A 1.00 mol/kg solution of KCl indicates that 1 mol (74.5 g) of KCl is dissolved in 1 kg of water.
- Molality is independent of temperature, unlike molarity, which is temperature-dependent due to volume change.
Example of Molality Calculation
- For 2.5 g of ethanoic acid (CH3COOH) in 75 g of benzene, the calculation of molality involves determining moles of ethanoic acid and converting the mass of benzene to kg (0.075 kg).
Henry's Law
- Henry’s Law states that the partial pressure of a gas in vapor phase is proportional to its mole fraction in solution, expressed as p = KH x, where KH is the Henry’s law constant.
- The relationship between solubility of gas and partial pressure highlights that different gases have distinct KH values at a given temperature.
Vapor Pressure and Mole Fractions
- Total vapor pressure over a solution is influenced by the mole fraction of components.
- It varies linearly, indicating that as the mole fraction of one component increases, the vapor pressure changes correspondingly.
- The minimal and maximal vapor pressures in a binary solution depend on the volatility of the components.
Raoult's Law
- Raoult’s Law states that the partial vapor pressure of each volatile component is directly proportional to its mole fraction in the solution.
- For ideal solutions, the mixing process leads to no heat absorption or evolution (ΔmixH = 0) and the volume of mixing is negligible (ΔmixV = 0).
- Ideal behavior is observed when intermolecular forces are consistent among A-A, B-B, and A-B types.
Non-Ideal Solutions
- Non-ideal solutions deviate from Raoult’s law under certain concentrations, exhibiting either positive or negative deviations.
- Positive deviation results in higher vapor pressure than predicted by Raoult's law, while negative deviation results in lower vapor pressure.
- Vapor pressure vs. mole fraction plots illustrate these deviations for non-ideal solutions.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Test your understanding of molarity calculations with this quiz focused on a specific example involving NaOH. You'll work through the process of calculating moles and converting volume to find molarity. Perfect for chemistry students looking to reinforce their knowledge.
