The specific heat capacity, or simply specific heat #(C)# of a substance is the amount of heat energy required to raise the temperature of one gram of the substance by one degree Celsius. Heat energy is usually measured in Joules #("J")# or calories #("cal")#.
The variables in the equation #q = mCDeltaT# mean the following:
#" let:"# #q="heat energy gained or lost by a substance"# #m="mass (grams)"# #C="specific heat"# #DeltaT="change in temperature"#
Note that #DeltaT# is always calculated as #"final temperature "-" initial temperature"#, not the other way around.
Therefore, you can look at that equation like this if it helps:
#"heat energy gained or lost by a substance"=("mass")("specific heat")(DeltaT)#
Example
How much heat energy is required to raise the temperature of #"55.0g"# of water from #"25.0"^@"C"# to #"28.6"^@"C"#? The specific heat of water is #"4.18""J"#/#"g"^@"C"#. This is a very well known specific heat value and will frequently show up in specific heat questions.
Unknown: #q# in Joules #("J")#
Known/Given:
specific heat of water #(C)# = #"4.18""J"#/#"g"^@"C"#
mass of water = #"55.0g"# #DeltaT# = #"28.6"^@"C"-"25.0"^@"C"# = #"3.6"^@"C"#
Equation: #q =mcDeltaT#
Solution: #q="55.0g" xx "4.18""J"#/#"g"^@"C"xx"3.6"^@"C"# #q# = #"827.64""J"#, which rounds to #8.28xx10^2"J"# due to significant figures.
