Ex. 1)How much heat is required to raise 400.0grams of water from 11.3?C to 91.7?C?
Ex. 2)What mass of iron would increase 34?C if 3970 joules of energy is added?
q= m?TCp…m= q/?TCp
m= 3970J/(34?C)(.449J/g?C) = 260g!
Ex. 3)If 202 grams of water at 70.0?C gains 2010 calories of heat, what will its FINAL temperature (Tf) be?
q= m?TCp…substitue ?T to…q= m(Tf – Ti)Cp…[q/mCp] = (Tf – Ti)…Tf = q/mCp + Ti (formula needed)
Tf = 2010calories/(202g)(1cal/g?C) + 70?C…10?C + 70?C = 80?C = Final Temperture!
*note: always round answer to nearest whole number!
Ex.4)2.5lb of water at 48?C will be at what temperature after 15,000 joules of heat are added?
convert lb to grams…2.5lb x (1kg/2.2lb) x (1000g/1kg) = 1.136grams
48?C + [15000J/(1136g)(4.18J/g?C)…48?C + 3.15?C = 51?C = Answer
Ex. 4)8750J of heat are applied to a piece of aluminum, causing a 56?C increase in its temperature. What is the mass of the aluminum?
(look up in chemistry reference table to find the specific heat of aluminum)
8750J/(36?C)(.897J/g?C) = 174g!