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# Chemistry unit 3 calculations gcse aqa Watch

1. DOES ANYONE KNOW HOW TO DO THIS QUESTION omg I know how to do it but I'm getting it wrong?

When 5.6g of iron fillings reacted completely with 200cm3 of copper(II) sulfate solution the temperature of the solution increased by 17 degrees Celsius. Calculate the energy change in kJ/mol of iron. Relative atomic mass of iron = 56

I had added 5.6g with 200cm3 (because we assume that 1cm3 = 1g, so its basically 200g) which equals 205.6g. Then I did Q = m x c x T ---> 205.6 x 4.2 x 17 = 14.7 kJ x 56 =823.2 kJ/moles

Ahhhhh help
2. (Original post by rm_27)
DOES ANYONE KNOW HOW TO DO THIS QUESTION omg I know how to do it but I'm getting it wrong?

When 5.6g of iron fillings reacted completely with 200cm3 of copper(II) sulfate solution the temperature of the solution increased by 17 degrees Celsius. Calculate the energy change in kJ/mol of iron. Relative atomic mass of iron = 56

I had added 5.6g with 200cm3 (because we assume that 1cm3 = 1g, so its basically 200g) which equals 205.6g. Then I did Q = m x c x T ---> 205.6 x 4.2 x 17 = 14.7 kJ x 56 =823.2 kJ/moles

Ahhhhh help
Just use the volume of solution don't add the mass of the solid iron

Then after that work out the moles of iron you have, then do Q/moles which will give you the enthalpy change.
3. So 200 x 4.2 x 17 =14.28 kJ/mol Then what? Confused with the mole thing you're talking about
4. (Original post by rm_27)
So 200 x 4.2 x 17 =14.28 kJ/mol Then what? Confused with the mole thing you're talking about
Take the 5.6g of iron you have, divide it by its Mr (56), then do the Q/whatever mole number you get

Is this for GCSE because im assuming you know what a mole is?, sorry
5. Yeah I do lol, and yes it GCSE. Ah, I understand it now, thank you
6. (Original post by rm_27)
Yeah I do lol, and yes it GCSE. Ah, I understand it now, thank you
You're welcome

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