So say I was doing your bog-standard magnesium and HCl reaction...

I'm measuring the temperature change of the HCl which would increase right? And what things apart from heat escaping to the environment and measuring errors could cause the result to not be quite right??

XShmalX

I'm measuring the temperature change of the HCl which would increase right? And what things apart from heat escaping to the environment and measuring errors could cause the result to not be quite right??

You are going to calculate the value of ΔH from the equation:

ΔH = mcΔT

and then divide by the number of moles reacted:

ΔH/mol = mcΔT/mol

so look for errors in every part of the equation..

Heating up the thermometer
Heating up the reaction vessel
Evaporation
Thermometer inaccuracy
Volume inaccuracy (or mass of liquids)
Hydrochloric acid/magnesium chloride solution SHC varying from that of water.
Gas escaping with heat energy
Mass of magnesium measured
Concentration of the HCl

Reply 2

XShmalX

OP

1

charco

You are going to calculate the value of ΔH from the equation:

ΔH = mcΔT

and then divide by the number of moles reacted:

ΔH/mol = mcΔT/mol

so look for errors in every part of the equation..

Heating up the thermometer
Heating up the reaction vessel
Evaporation
Thermometer inaccuracy
Volume inaccuracy (or mass of liquids)
Hydrochloric acid/magnesium chloride solution SHC varying from that of water.
Gas escaping with heat energy
Mass of magnesium measured
Concentration of the HCl

And its exothermic so ΔH for HCl would be negative whilst q would be positive right?