Specific heat is the amount of heat required to raise the temperature of one gram of a substance one degree celsius. The equation for calculating the amount of heat required for a given temperature change in a given mass of substance is:
q = mc `Delta` T where:
q = heat
m = mass = 186g
c = specific heat = 4.186 Joules/gram-ºC
`Delta` T = change in temperaturge = 69ºC-29ºC = 4ºC
q =...
Specific heat is the amount of heat required to raise the temperature of one gram of a substance one degree celsius. The equation for calculating the amount of heat required for a given temperature change in a given mass of substance is:
q = mc `Delta` T where:
q = heat
m = mass = 186g
c = specific heat = 4.186 Joules/gram-ºC
`Delta` T = change in temperaturge = 69ºC-29ºC = 4ºC
q = (186 g)(4.186 J/g-ºC)(40ºC) = 31,099 J = 31,000 J rounded to 2 significant digits.
To change this value to kilojoules, multiply by the conversion factor 1kJ/1000 J:
(31,000 J)(1 kJ/1000 J) = 31 kJ
Another method of calculating the answer is kJ is to change the specific heat of water to kJ/g-ºC:
(4.186 J/g-ºC)(1 kJ/1000 J) = .004186 kJ/g-ºC
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