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VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Chemistry => Topic started by: Studyinghard on June 04, 2010, 05:22:14 pm

Title: Chemology 08
Post by: Studyinghard on June 04, 2010, 05:22:14 pm
Question 3
How many oxygen atoms are present in 0.0500 mol carbon dioxide?

a) 3.01 x 10^22

b) 6.02 x 10^22

c) 6.02 x 20^23

d) 1.20 x 10^24

Answer says C but im definite its B


Question 16
Acid X and acid Y are both monoprotic weak acids of equal concentration. Acid X is
a stronger acid than acid Y. Which statement about acid X and acid Y is correct?

A. Acid Y is completely ionised in solution.
B. The solution of acid X is less ionised than the solution of acid Y.
C. The solution of acid X has a lower pH than the solution of acid Y.
D. 1 mole of acid Y requires a greater volume of 1.0M NaOH for neutralisation than 1 mole of acid X.


Answer says C for that one but how can one have a lower pH than the other if their concentration is the same. Isnt PH depending on concentration? :S




Title: Re: Chemology 08
Post by: Transcendent on June 04, 2010, 05:23:53 pm
I encountered the same problem with question 3. I think it's an error with the answers. Although i'm unsure about question 16.
Title: Re: Chemology 08
Post by: Martoman on June 04, 2010, 05:25:09 pm
Ok.

They are high on 1. I think they are assuming 0.5 mol, then their answer makes sense.

You are certainly right.

16)

If it is a stronger acid it will ionise to a greater extent >> more H ions >> lower pH.
Title: Re: Chemology 08
Post by: Studyinghard on June 04, 2010, 05:27:26 pm
Ok.

They are high on 1. I think they are assuming 0.5 mol, then their answer makes sense.

You are certainly right.

16)

If it is a stronger acid it will ionise to a greater extent >> more H ions >> lower pH.

What defines "strongness" of an acid?
Title: Re: Chemology 08
Post by: Martoman on June 04, 2010, 05:28:09 pm
Its willingness to donate a proton (H ion).
Title: Re: Chemology 08
Post by: Studyinghard on June 04, 2010, 05:31:08 pm
oh yeah aha. ffffail mistake this close to an exam
Title: Re: Chemology 08
Post by: Potter on June 04, 2010, 08:38:07 pm
In the solutions, they used .5mol instead of .05mo so it's a mistake on their behalf. Imo, the chemology exam was crap anyway.
Title: Re: Chemology 08
Post by: Stroodle on June 05, 2010, 03:36:07 am
I didn't do this exam cause the name put me off. Sounds like an exam for chemtards.
Title: Re: Chemology 08
Post by: Martoman on June 06, 2010, 12:15:58 am
Hamlet sounds like an innocuous little village........ for inbred people....