H=mc(triangle)T (1 Viewer)

[nsbrando]

Can you guys explain what the use of this formula and an example of the use of the formula.

 

[qwerty44]

Don't know chemistry, but that 'triangle' is delta. Δ

 

[Alkenes]

what the.... what topic is this??? :S

 

[soloooooo]

It is to do with the energy required to heat water by 1 degree Celsius isn't it?

 

[Alkenes]

ohhh you mean molar heat of combustion...
You use this to calculate the molar heat of combustion of alkanols.

So you use it in three steps.
1. calculate delta H
2. find no of moles (n=m/MM)
3. Molar heat of combustion = delta H/ n

 

[Alkenes]

no that is 'c' specific heat capacity of water

It is to do with the energy required to heat water by 1 degree Celsius isn't it?

 

[D94]

This is the formula used to determine the thermal energy of an object. It can be used to determine the amount of energy needed to raise the temperature of (say) water, or it can be used with the Latent Heat formula to determine the amount of energy needed to change the state of the object. You will need to know the mass of the object, the specific heat of the object, and the change in temperature (which can be measured in C or K), in order to determine Q (or as you have it, H).

 

[Aesytic]

isn't there meant to be a negative sign?

 

[RealiseNothing]

isn't there meant to be a negative sign?

There is meant to be.

 

[Alkenes]

yes

isn't there meant to be a negative sign?

 

[teeah]

Just a super quick summary of what everybody else said above:

H = -mCT, where:
H = amount of energy needed
m = mass of what the energy is being applied to (water)
C = specific heat capacity of water (to raise the temperature of water by 1 degree Celsius)
T = change in temperature (final – initial)
If the value of H is negative then the reaction is exothermic (releases heat), which is what happens with the combustion of alkanols, i.e. ethanol.

um, replace the squares with the triange (for delta)..evidently i cant just copy and paste it in, lol.

hope this helps.