DON'TTHINK THAT WAY because I'm about to prove you wrong.

Enthalpy calculations=the usage of MOLES -insert dramatic scream-

And the return of the mole also means the return of sig figs, btdubs. -insert double dramatic scream-

That my friends was a double double, double double combo. (:

Let's get started:

ΔH--> change in energy of a reaction; expressed in kJ/mol

Here is an example:

C10H8+12O2-->10CO2+4H20+436kJ

Hence, ΔH=

1)

__-436kJ__

1 mol C10H8

2)

__-436kJ__

12 mol O2

3)

__-436kJ__

10 mol CO2

4)

__-436kJ__

4 mol H2O

Once you've identified these, it will be easy to do conversions.

eg. Calculate how many grams of O2 would be needed to produce 1500kJ of energy.

-1500kJ x

__12 mol O2__x

__32g__= 1321.1 kJ

-436kJ 1 mol

**SIG FIGS!!** So, the answer is 1300 kJ.

Watch this video if you're still confused!!

GOOD LUCK WITH THIS CONFUSING SECTION!! :D

Written by Jialynn.

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