1. The Specific Heat of Water

2. 1 g 1 o Specific Heat: The heat required to raise 1 g of water1 o C. The specific heat of water is 4.18 joules of heat per gram of water. We write: 4.18 J/g o C

3. How much energy is required to change 220g of water 1.0 o C? It would take 4.18 joules for every gram. It would take (4.18)(220) = 920 J It would take 920J of energy.

4. How much energy is required to change 1.0g of water by 25.0 o C? It would take 4.18 joules for every 1.0 o C. It would take (4.18)(25.0) = 105 J It would take 105J of energy.

5. How much energy is required to change 220.0g of water by 25 o C? It would take 4.18 joules for every 1.0g changing by 1.0 o C. It would take (220.0)(4.18)(25) = 23045 J It would take 23000J of energy.

6. Therefore, the formula for specific heat of water is … Q = mc  t Q = heat required (J) M = mass of the water (g) C = specific heat of water (J/g o C)  T = temperature ( o C)

7. Q = mc  t What mass of water absorbs 3050J of heat energy when it is heated from 10.0 o C to 30.0 o C? Q = 3050J C = 4.18J/g o C  t = 20.0 o C

8. 3050=m(4.18)(20.0) 3050=m(83.6) Cancel the 83.6 so the m will be alone. Do this by doing the opposite operation. Divide by 83.6 3050=m(83.6) 83.6 36.5 = m The mass is 36.5g

9. All substances have a specific heat. Specific Heat (g/J o C) Aluminum Copper Gold Lead Silver 0.900 0.386 0.126 0.128 0.233 Zinc Mercury Alcohol Granite Glass 0.387 0.140 2.40 0.790 0.840

10. How much heat is needed to raise the temperature of 10.0g of gold by 5.0 o C? Q = ? J m = 10.0 g c = 0.126 J/g o C  t = 5.0 o C Q = mc  t =(10.0)(0.126)(5.0) = 6.3 J of heat is needed to raise the temperature of 10.0g of gold by 5.0 o C.