qn help (1 Viewer)

Masaken

Unknown Member
Joined
May 8, 2021
Messages
1,689
Location
in your walls
Gender
Female
HSC
2023
1663584389735.png
1663584489984.png

how would you go about solving this? not sure what to do with either of these questions, was completely lost when i saw these
thanks in advance, answers are: 11 - B, 19 - D
 

carrotsss

New Member
Joined
May 7, 2022
Messages
4,653
Gender
Male
HSC
2023
For question 19 I believe the answer is wrong, I did that paper and I had no idea where I went wrong so I sent it to my friend who is godly at chem and even he had no idea.
 

Masaken

Unknown Member
Joined
May 8, 2021
Messages
1,689
Location
in your walls
Gender
Female
HSC
2023
For question 19 I believe the answer is wrong, I did that paper and I had no idea where I went wrong so I sent it to my friend who is godly at chem and even he had no idea.
What would the answer be? I have no idea how to get either of these qns ;-;
 

carrotsss

New Member
Joined
May 7, 2022
Messages
4,653
Gender
Male
HSC
2023
What would the answer be? I have no idea how to get either of these qns ;-;
For question 19:
- Find the number of moles of barium hydroxide
- Find the concentration of barium hydroxide in solution A using the moles found and c=n/v
- Then use c1v1=c2v2 to find v2 (the answer)
(You should get B)
 

someth1ng

Retired Nov '14
Joined
Sep 18, 2010
Messages
5,558
Location
Adelaide, Australia
Gender
Male
HSC
2012
Uni Grad
2021
Q11. It's a sealed reaction vessel so none of the details matter apart from the total mass of the starting materials.
m(Hg) = 10 mL * 13.546 (g/mL)
m(O2) = 150 mL * 0.001429 (g/mL)

m(total) = m(Hg) + m(O2) = 135.67 g (i.e. B)
 

someth1ng

Retired Nov '14
Joined
Sep 18, 2010
Messages
5,558
Location
Adelaide, Australia
Gender
Male
HSC
2012
Uni Grad
2021
Q19.

M(Ba(OH)2) = 171.23 g/mol
n(Ba(OH)2) = (17.1 g)/(171.23 g/mol) = 0.100 mol
c(Ba(OH)2) = 0.100 mol/0.100 L = 1.00 M

c1v1=c2v2
1.00 M * 0.00500 L = 0.04 M * v2
v2 = 0.125 L = 125 mL

As a sanity check, you can see that from 1.00 M to 0.04 M is 25x dilution. So the new volume is 5*25 mL = 125 mL.
 

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Top