Self assessment
Question 1 of 8
For a sample of 50 cm3 calcium hydroxide (limewater) which of the following statements is true?
A
It contains more hydrogen ions than hydroxide ions in solution.
B
It contains equal numbers of hydrogen ions and hydroxide ions.
C
It contains the same number of hydroxide ions as 50 cm3 of pure water.
D
It contains more hydroxide ions than 50 cm3 of pure water.
What is the pH of 10 mol dm–3 hydrochloric acid?
A
1
B
–1
C
2
D
–2
How would you rearrange the equation pH = – log10 [H+] in order to calculate the concentration from a measured pH value?
A
[H+] = pH/–log10
B
[H+] = –log10 pH
C
[H+] = 10–pH
D
pH = 10pH
Work out the pH of a solution that is prepared by diluting 15 cm3 of 0.20 mol dm–3 nitric acid with water up to a total volume of 150 cm3.
A
2.5
B
0.7
C
pH 1.4
D
1.7
The pH reading for a dilute solution of sulfuric acid, H2SO4, is 2.7. What is the concentration of hydrogen ions, and what is the concentration of the acid?
A
2.0 x 10–3 mol dm–3 and 1.0 x 10–3 mol dm–3.
B
2.0 x 10–3 mol dm–3 and 4.0 x 10–3 mol dm–3.
C
2.0 x 10–3 mol dm–3 and 2.0 x 10–3 mol dm–3.
D
2.0 mol dm–3 and 1.0 mol dm–3.
What might you say to a student who was convinced that mixing 50 cm3 of water with a 50 cm3 sample of dilute sulfuric acid would increase its pH number by one unit?
A
I would show the student this scenario practically and demonstrate the actual pH value obtained.
B
I would ask the student to read their notes from class again.
C
We would do this practical example and take a pH reading if time permits, and I'd explain to the student where pH numbers come from, why each pH unit actually represents a 10-fold change in concentration and follow up with some practice questions.
D
I would tell the student that I am so disappointed that he/she did not listen in class today.
What is the concentration of H+ ions in a solution of pH 12.7?
A
2.0 x 10–13 mol dm–3
B
5.0 x 1012 mol dm–3
C
1.0 x 10–13 mol dm–3
D
2.0 x 10–12 mol dm–3
A solution of diluted acid has a pH of –0.3. What is the concentration of H+ ions?
A
2.0 mol dm–3
B
0.5 mol dm–3
C
2.0 x 10–2 mol dm–3
D
1 mol dm–3