Chemistry 30: Module 8: Lesson 2 1 Assignment Booklet
MODULE 8: LESSON 2 ASSIGNMENT
Fatima Raza
This Assignment is worth 13 marks. The value of each question is stated in the left
margin.
Use the following informati
...
Chemistry 30: Module 8: Lesson 2 1 Assignment Booklet
MODULE 8: LESSON 2 ASSIGNMENT
Fatima Raza
This Assignment is worth 13 marks. The value of each question is stated in the left
margin.
Use the following information to answer the first question.
Acid pH of 0.10 mol/L solution
HNO3(aq) 1.0
HNO2(aq) 2.2
1. Nitric acid and nitrous acid are two acids associated with acid deposition.
(2 marks) a. Use the information above to identify which of the acids is a strong acid, and
which is a weak acid. Support your reasoning without the use of a calculation.
Answer:
The pH scale is logarithmic, which means that an increase or decrease of an
integer value changes the concentration by a tenfold. For example the Ph of
1.0 is 10 times more acidic than the ph of 2.2, or the Ph of 11 ten times more
basic than the Ph of 10. On the Ph scale as we move from 1 to 7 the acidity
of the solution starts to decrease and from 7 to 14 the solution starts to
become more basic. Since up there HNO3 pH is 1.0 and HNO2's pH is 2.2
this shows that the pH of HNO3 is higher which makes it the stronger acid.
(2 marks) b. Support your answer to questions 1a using a calculation.
Answer:
Concentration of [H+] in HNO3 --> 10-pH
0.1/0,1 X 100 = 0.1 mol/l
Therefore HNO3 has 100% dissociation and is a strong acid.
Conc of H+ in HNO3 --> 10-pH
= 10-22
= 6.309 x 10-3mol/l
6.309 x 10-3/0.1 X 100
= 6.31%
Therefore it is a weaker acid compared to HNo3 because ions do not fully
dissociate
(2 marks) c. Identify one other difference that you would expect if you tested these two
solutions. Include the name of the test, the expected results for each solution,
and the reasoning for the expected difference.
Answer:
Chemistry 30: Module 8: Lesson 2 2 Assignment Booklet
Another result which I would expect is proton exchange the weaker on will be less
stable and will easily give off its proton while the stronger acids will hold on to its
protons more firmly.
(3 marks) 2. Complete “Section 16.1” question 10 on page 721 of the textbook.
Answer:
pH 1.57= [H+] of 0.0269
0.0269 x .25L= 0.00672 moles
0.00672 moles x 36.5 g/mole HCl= 0.245 g HCl
(4 marks) 3. Complete “Section 16.1” question 13 on page 721 of the textbook.
Answer:
Molarity ;
60.0 kg = 60000 g
60000 g / 60.0 g/mol = 1000 moles
1000 moles / 1250 L = 0.800 M
Hhydrogen ion concentration:
0.800 M times 0.0048 = 0.00384 M (this is the [H+])
Now, we can do the pH:
pH = -log 0.00384 = 2.416
pOH = 14 minus 2.416 = 11.584
More Basic.
Once you have completed all of the questions, submit your work to your teacher.
[Show More]
