Rabu, 09 Februari 2011

Heat


* Heat type 
Formulas :

\!Q=\!m\times\!c\times\Delta\!t

with the following provisions:
Q = Heat received a substance (Joule, kilojoules, calories, kilocalories)
= Mass of substance (Gram, Kilogram)
 C
= Heat type (Joule / kilogram ° C, Joule / gram ° C, Calories / gram ° C)
 \Delta\!t 
= Changes in temperature (° C) → (t2 - t1)

* To find the heat type, the formula is:
\!c=\frac{Q}{\!m\times\Delta\!t}

* To find the mass of substance, the formula is:
\!m=\frac{Q}{\!c\times\Delta\!t}


* Heat Capacity
Heat capacity is the amount of heat needed by the body to raise its temperature 1 ° C.

* The formula for heat capacity:
 rovided that:

Q 
= Heat received a substance (Joule, kilojoules, calories, kilocalories)
 H
= Heat capacity (Joules / ° C)
 M
= Mass of substance (Gram, Kilogram)
 C
= Heat type (Joule / kilogram ° C, Joule / gram ° C, Calories / gram ° C)
\Delta\!t  
= Changes in temperature (° C) → (t2 - t1) 
\!H=\frac{Q}{\Delta\!t}

\!H=\frac{\!m\times\!c\times\Delta\!t}{\Delta\!t}

\!H=\!m\times\!c

*  Heat melting 

     Formulas:

\!Q=\!m\times\!L

    with the following provisions:

= Heat received a substance (Joule, kilojoules, calories, kilocalories)
= Mass of substance (Gram, Kilogram)
= Heat melting substances (Joule / kg, kilojoules / kilogram, joule / gram)

* Steam Heat  
   Formulas:

\!Q=\!m\times\!U

with the following provisions:
= Heat received a substance (Joule, kilojoules, calories, kilocalories)
= Mass of substance (Gram, Kilogram)
= Heat steam substances (Joule / kg, kilojoules / kilogram, joule / gram)

* Principle Black  Formulas:
\!Q_{terima}=\!Q_{lepas}


 
The principle of Black: The amount of heat received equal to the amount of heat released
*Example Problem:

1.How much heat energy needed to vaporize 5 Kg of water at its boiling point, if the steam heat 2.26 million Joules / Kilogram? Answer: Given: m = 5 kg
             
U = 2,260,000 J / Kg Asked: Q =..... ?
Answer Q = m x U
        
= 5 kg x 2.26 million J / Kg
        
= 11,300,000 J         = 11.3 x 106 J








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