Year 11 Chemistry Module 2.3

Concentration and molarity

What is concentration?

A measure of how much solute is dissolved in a given amount of solven or solution

What is molarity?

The measure of a concentration of a solution

What is dilution?

The process of lowering the concentration of a solute in a solution by adding more solvent (like water).

What is a solute

The substance that is dissolved in a solution

What is a solvent?

The substance that dissolved the solute

What is a solution?

A homogenous mixture formed when a solute dissolves in a solvent

What is a stock/standard solution?

A concentrated solution that is used to prepare more dilute solutions

What is a concentrated solution?

A solution that contains a large amount of solute relative to solvent.

What is a dilute solution?

A solution that has a small amount of solute compared to solvent.

What is a saturated solution?

A chemical solution containing the maximum concentration of a dissolved substance (solute) for a given solvent and temperature

What is an unsaturated solution?

A chemical mixture in which the concentration of the dissolved solute is lower than the solvents maximum solubility limit. Essentially, it does not contain the maximum amount of a dissolved solute.

How can different types of solutions be categorised?

Based on physical state, based on concentration, based on solvent

What are different physical states that can classify solutions?

Gas, liquid, solid.

What are different concentrations that can classify solutions?

Dilute, concentrated, saturated, unsaturated

What are different are the names for the different solutions that are classified off of their solvent?

Aqueous solution (water is solvent), non-aqueous solution (water is not solvent)

What unit is commonly given to the concentration of the solute

M - molarity

What does molarity measure?

The number of moles of solute in one litre of solution

True or false: Molarity only measures one litre of the final solution

True: It measures one litre of the final solution

What are ways to measure concentration?

Grams per litre, percentage by mass, percentage by volume, percentage mass/volume, parts per million.

What does concentration in grams per litre indicate?

The mass, in grams, of sulte dissolved in one litre of the solution.

What is the formula for concentration in grams per litre?

Mass of solute(g)/volume of solution

What does the percentage by mass of concentration indicate?

The mass of solute, measured in grams, present in 100g of the solution.

What is the formula for concentration in percentage by mass?

Mass of solute/mass of solution x 100

When measuring concentration in percentage by volume, what does the v/v mean?

Indicates that the percentage is based on volumes of both solute and solution. Records both volumes.

What does percentage by volume of concnetration indicate?

Measures the volumes of both solute and solution per 100ml of a solution.

What is the formula for concentration percentage by volume?

(volume of solute/volume of solution) x 100

What is percentage by mass/volume of a concentration?

Describes the mass of solute, measured in grams, present in 100ml of the solution

What is the formula for concentration percentage by mass/volume?

(Mass of solute (g) / volume of solution (ml)) x 100

When very small quantities of solute are dissolved to form a solution, it is usually measured using this type of measurement.

Concentration in parts per million

What is concentration in parts per million?

Expressed as the mass in grams of solution dissolved in 1,000,000g of solution, or, the mass in milligrams of solute dissolved in 1kg of solution.

What are the two formulas used to calculate the concentration of a solution in parts per million?

(Mass of solute (mg) / mass of solution (kg)) x 10^6

How do you dilute solutions from one concentration to a lower value?

Adding more solvent

How do you dilute solutions?

A definite volume of the concentration solution is measured out with a pipette and placed into a volumetric flask.

Then, sufficient solvent is then added to the flask to make the solution up to the calibrated mark.

True or false: Dilution alters the number of moles of solute present.

False: Dilution does not alter the number of moles of solute present.

What is the formula for dilution?

N1 = c1v1 = n2 = c2v2 OR c1v1=c2v2