• We need your support!

    We are currently struggling to cover the operational costs of Xtremepapers, as a result we might have to shut this website down. Please donate if we have helped you and help make a difference in other students' lives!
    Click here to Donate Now (View Announcement)

Chemistry: Post your doubts here!

Messages
70
Reaction score
171
Points
43
Last edited:
Messages
6,392
Reaction score
27,000
Points
698
q9
upload_2014-6-1_17-31-40-png.44475


q 11 assume the moles used up were x.
upload_2014-6-1_17-33-28-png.44476

so u have equation

4= x^2/(1-x)^2

taking square roots on both sides we have

2=x/(1-x)

2-2x=x

2/3 =x


since volume is not mentioned you can assume it to be 1 dm^3
where the square come from :eek: in ques 11
 
Messages
8,477
Reaction score
34,837
Points
698
Messages
639
Reaction score
3,684
Points
253
q.1
moles = (V × M)/1000

mole ratio of KOH to CaSO₄ = 2 : 1
moles of KOH = (25 × 0.01)/1000
moles of KOH = 2.5 × 10⁻⁴

hence moles of CaSO₄ = (1/2) × 2.5 × 10⁻⁴ = 1.25 × 10⁻⁴

Concentration of CaSO₄ = (1.25 × 10⁻⁴ × 1000)/50
Concentration of CaSO₄ = 2.5 × 10⁻³ mol/dm³
Answer: A
 
Messages
70
Reaction score
171
Points
43
Messages
1,764
Reaction score
3,472
Points
273
q.1
moles = (V × M)/1000

mole ratio of KOH to CaSO₄ = 2 : 1
moles of KOH = (25 × 0.01)/1000
moles of KOH = 2.5 × 10⁻⁴

hence moles of CaSO₄ = (1/2) × 2.5 × 10⁻⁴ = 1.25 × 10⁻⁴

Concentration of CaSO₄ = (1.25 × 10⁻⁴ × 1000)/50
Concentration of CaSO₄ = 2.5 × 10⁻³ mol/dm³
Answer: A
how did you know the volume for CaSO4 was 1000 dm^3?
 
Top