Q=mc∆T

[Taledin]

I do not understand. It is an equasion in Physical Science. Would anyone be willing to give me a hand?

 

[Atown]

context???? if i remember, Q = metamorphisis (c i dont remember) change of temperature?

 

[Stc95]

mass X speed of light X change in temp???

 

[Hescominsoon]

google is your friend..

http://www.google.com/search?q=Q=mc...s=org.mozilla:en-US:official&client=firefox-a

 

[Odale]

Found this on Google:

Q = m*c*(delta T)
Q = heat energy
m = mass
c = specific heat
delta t = change in temperature (= final - initial temp)

Remember, in a closed system, heat gained by one thing equals the heat lost by another.

Heat is a form of energy, meausred in Joules (sometimes calories, but the official SI unit is Joules), depending on the value you use for the specific heat, it is common to use grams or kilograms for the mass measurement. Again, depending on the value of the specific heat, most commonly, you'll use temperature in terms of degrees C (or perhaps K, a change of 1 degree C = change of 1 K).

 

[Whon]

The best way I could help on the equation is to put it into an example:

Let's say you take a pot of tap water and put it on the stove on high. You heat it til it boils and want to know how much energy (heat) you added to it to raise the temp. Let's look at it:

If we used a pound of water.
Initial water temp for tap water: about 50 degrees F
Water boils at 212 degrees F
The specific heat of water is 4.186 joules/gram(degrees Centigrade)

Now most therodynamic equations work best in Metric units so I would convert

1 lb water = 453.59 grams of water
Temp conversion F=C(1.8)+32
so C=(F-32)/1.8

That give you tap water at 10 degrees C and boiling water at 100 degrees C

Now we have all our variables lets put them into the Q=Mc(deltaT)

M= 453.59 grams
c= 4.186 joules/gram(degrees Centigrade)
deltaT= final temp minus initial temp = 100 degrees C - 10 degrees C = 90 degress C

You multiply through and notice that the Mass and temp units cancel each other out (ALWAYS CHECK YOUR UNITS) and end up with

Q= 170885.4966 Joules or 170.89 Kilojoules of energy was added to the water by the stove to bring it to a boil.

on a side note be careful on your deltaT if something is cooling off (aka losing energy) the deltaT will be a negative making the whole equation negative. A negative Q means that the energy is lost not gained.

Hope that helps (and yes I did take college thermodynamics I was a mechanical engineer after all )

 

[Icthus]

42!

 

[Taledin]

I was a mechanical engineer after all

Nice. Thanks for all of your help and the example was killer.

 

[Stc95]

ahh i was so close... only my c was off...

curse you speed of light!!!! /fistshake