C4.6 - Expressing concentrations

Question 1

Chemists often carry out their concentration reactions in what?

Answer 1

Chemists often carry out their concentration reactions in solution

Question 2

Chemists often carry out their concentration reactions in solution.
What is the solvent usually?

Answer 2

The solvent is usually water

Question 3

To record, interpret and communicate their results, chemists need to express what?

Answer 3

To:
1. Record
2. Interpret
3. Communicate
their results, chemists need to express the concentration of the solutions they use

Question 4

To record, interpret and communicate their results, chemists need to express the concentration of the solutions they use.
What should other chemists be able to do?

Answer 4

Other chemists should be able to repeat published experiments to verify data

Question 5

To record, interpret and communicate their results, chemists need to express the concentration of the solutions they use.
Other chemists should be able to repeat published experiments to verify data.
So what do chemists do?

Answer 5

So chemists quote the amount of substance (solute) dissolved in a certain volume of the solution

Question 6

The units to express concentration

Answer 6

The units to express concentration is g/dm³

Question 7

How many cm³ is 1 dm³ equal to?

Answer 7

1 dm³ is equal to 1000 cm³

Question 8

Concentration equation

Answer 8

Concentration (g/dm³) = Amount of solute (g) ÷ Volume of solution (dm³)

Question 9

If you are working in cm³, what do you always do?

Answer 9

If you are working in cm³, you always convert the volume to dm³ by dividing it by 1000

Question 10

If you are working in cm³, you always convert the volume to dm³ by dividing it by 1000.
Alternatively, what is the equation for when the volume is in cm³?

Answer 10

The equation for when the volume is in cm³ is:

Concentration (g/dm³) = Amount of solute (g) ÷ Volume of solution (cm³) x 1000

Question 11

How can you increase the concentration of an aqueous solution?

Answer 11

You can increase the concentration of an aqueous solution by:

1. Adding more solute and dissolving it in the same volume of its solution
2. Evaporating off some of the water from the solution

Question 12

Chemists often carry out their concentration reactions in solution.
The solvent is usually water, but can be other liquids, such as what?

Answer 12

The solvent is usually water, but can be other liquids, such as ethanol

Question 13

You can increase the concentration of an aqueous solution by adding more solute and dissolving it in the same volume of its solution, or evaporating off some of the water from the solution so you have what?

Answer 13

You can increase the concentration of an aqueous solution by:
1. Adding more solute and dissolving it in the same volume of its solution
Or,
2. Evaporating off some of the water from the solution so you have the same mass of solute in a smaller volume of solution