Molarity: is the number of moles of solute per liter of solution, providing a direct measure
of
the concentration
of a solution.
Molality: is the number of moles of solute per kilogram of solvent, making
it independent of
temperature changes.
Mole fraction:is the ratio of the number of moles of a component to
the total number of moles
in a solution, crucial for multi-component solutions.
These units play a vital role in accurately
expressing the
concentration of solutions in various scientific contexts.
What is molality and how is it calculated?
Molality is the number of moles of solute in 1000 g (1 kg) of the solvent. It is calculated by dividing the mass of the solute by the molar mass of the solute and the mass of the solvent in kg.
Explain the difference between molality and molarity.
Molality is based on the mass of the solvent, while molarity is based on the volume of the solution. Molality doesn't change with temperature, but molarity does.
Define mole fraction and its significance in solutions.
Mole fraction is the ratio of the number of moles of a component to the total number of moles in a solution. It is important for determining the proportion of each component in a mixture.
How is mole fraction calculated for a solution with multiple components?
For a solution with components A, B, and C, the mole fraction of each component is calculated by dividing the number of moles of the component by the total number of moles in the solution.
Explain the concept of parts per million (ppm) in concentration units.
Parts per million (ppm) is a unit of concentration used for very small concentrations, indicating one part of solute per million parts of solution.
What is the sum of mole fractions of all components in a solution?
a) Less than one
b) Equal to one
c) Greater than one
d) Variable
Answer: b) Equal to one
Which solution type does not obey Raoult’s law?
a) Ideal solutions
b) Non-ideal solutions
c) Dilute solutions
d) Saturated solutions
Answer: b) Non-ideal solutions
What is the concentration unit for a gas in a liquid solution?
a) Molarity
b) Molality
c) Mole fraction
d) Percentage composition
Answer: c) Mole fraction
Which type of solution has a freezing point independent of the amount of solute?
a) Dilute solution
b) Concentrated solution
c) Saturated solution
d) Ideal solution
Answer: d) Ideal solution
What is the concentration unit based on weight of solute in a liquid solution?
a) Percentage weight/weight
b) Percentage volume/volume
c) Molality
d) Molarity
Answer: a) Percentage weight/weight