Pls help Chem Questions (1 Viewer)

[ebbygoo]

Hey.
Im stuck pls help.

Q1: Combustion of C to CO2 gives 393kJ per mol. 1kg burnt. How much ice at 273 could be melted to give water at 100degrees celcius?

Q2: Calculate internal energy change of CaCO3 -> CaO + CO2 at 25 degrees celsius.

I have the answers but no working and struggling bad ey.
Help much appreciated.

 

[ThreeSciences]

Hey.
Im stuck pls help.

Q1: Combustion of C to CO2 gives 393kJ per mol. 1kg burnt. How much ice at 273 could be melted to give water at 100degrees celcius?

Q2: Calculate internal energy change of CaCO3 -> CaO + CO2 at 25 degrees celsius.

I have the answers but no working and struggling bad ey.
Help much appreciated.

C + O2 -> CO2 + 393kJ (exothermic reaction)

ΔH = mCΔT (we can neglect the "-" as we already know that this is an exothermic reaction; we simply need to know the magnitude)
m = ΔH/CΔT

Mass of Carbon = 1kg (1000g)

Number of moles = M/MM (mass/molar mass)
= 1000g / 12.01
= ~83.264 moles

Energy released = 83.264moles * 393kJ/mol
= 32,722,752J.

Initial temperature = -273C
Final temperature = 100C
ΔT = 100C - (-273C) = 373C

m = 32,722,752J / (4.18)(373)
= ~20987.6kg of water that can be boiled from burning 1kg of Carbon

Is that right?