[lagoom]

what do you write in a n equation to represent 'heated'
for example, how would you represent heated hydrated calcium sulphate

CaSO4 + ??? --> calcium sulphate + water

and if its oxygen, how come theres hydrogen (in water) on the other side :s

thanks

[Achilles99]

CaSO4.xH2O____> with heat above it :P
Thats how I always do it anyway

[lagoom]

Originally Posted by Achilles99

CaSO4.xH2O____> with heat above it :P
Thats how I always do it anyway

thanks,
can you help me work out what 'x' would be if the mass of:
hydrated copper sulphate crystals was 2.49g
anhydrous copper sulphate crystals was 1.96g
the mass of water lost due to heating was 0.53g ??
can you also make sure i've worked out the above valuse correctly aswell:
crucible and lid: 36.12g
crucible, lid and crystals before heating: 38.61g
crucible, lid and crystals after heating: 38.08g

THANK YOU SO MUCH!!

[xSkyFire]

Originally Posted by lagoom

thanks,
can you help me work out what 'x' would be if the mass of:
hydrated copper sulphate crystals was 2.49g
anhydrous copper sulphate crystals was 1.96g
the mass of water lost due to heating was 0.53g ??
can you also make sure i've worked out the above valuse correctly aswell:
crucible and lid: 36.12g
crucible, lid and crystals before heating: 38.61g
crucible, lid and crystals after heating: 38.08g

THANK YOU SO MUCH!!

0.53/H2O RMM = moles of H20
1.96/CaSO4 RMM = moles of CaSO4

work out the ratio from that o_o

[lagoom]

Originally Posted by xSkyFire

0.53/H2O RMM = moles of H20
1.96/CuSO4 RMM = moles of H2O

work out the ratio from that o_o

i meant calcium sulphate not copper sulphate, sorry

0.53/(2+16)= 0.0294
1.96/(40.1+32.1+64)=0.0144
0.0144/0.0294= 0.5

x = 1/2 ?

[xSkyFire]

Originally Posted by lagoom

i meant calcium sulphate not copper sulphate, sorry

0.53/(2+16)= 0.0294
1.96/(40.1+32.1+64)=0.0144
0.0144/0.0294= 0.5

x = 1/2 ?

Sorry made 2 mistakes lol, dunno what I was typing

Anyway if you got 2 moles of water to 1 mole of CaSO4 then it's most likely CaSO4.2H2O

[Asparagus]

CaSO4.xH2O ----> CaSO4 + xH2O

2.49g CaSO4.xH2O and 1.96g CaSO4

1:1 mole ratio of hydrated CaSO4 to anhydrous CaSo4

moles of CaSO4 = 1.96/136
= 0.0144117647

Therefore you have 0.0144117647 moles of CaSO4.xH2O

0.0144117647 = 2.49/(136 + 18x)

Rearrange to get x = 2.043
So x = 2 and the hydrated CaSO4 is CaSO4.2H2O

(An alternative way)