# Enthalpy Changes??

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#1
2.78g of potassium carbonate
30 ml of 2.00 mol dm-3 of HCl
temperature change= +6 degrees

Can someone explain each step of calculating the enthalpy change? Thanks
0
6 years ago
#2
Q=mc(deltaT)
(deltaH)=Q/n
0
6 years ago
#3
I prefer delta H = minus Q/n

That way, if you define delta T = final temp. - initial temp., then exothermic reactions automatically get a negative sign.
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#4
(Original post by Infraspecies)
Q=mc(deltaT)
(deltaH)=Q/n
I know the equation but when I have it I seem to struggle- I don't understand when you use the measurements of the reactants
0
#5
2.78g of potassium carbonate
30 ml of 2.00 mol dm-3 of HCl
temperature change= +6 degrees

Can someone explain each step of calculating the enthalpy change? Thanks
0
6 years ago
#6
What do all the letters refer to?

Q = ?
m = ?
c = ?
T = ?
n = ?
0
6 years ago
#7
(Original post by Pigster)
What do all the letters refer to?

Q = ?
m = ?
c = ?
T = ?
n = ?
Q = Energy Transferred (J)
m =Mass (kg)
c= Specific Latent Heat
Delta T= Temperature change
n= I don't have any clue,that not in my formula
0
6 years ago
#8
n = amount i.e. n = m/Mr (or n = m/RFM, et.al. depending on what you're taught)

You're trying to work out delta H, enthalpy change PER MOLE. To work that out, you work out the energy change, then divide that by the number of moles you have.

Also, mass is in g in chemistry. They tend to use kg in physics.
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