1. Specific Heat Capacity Weather Unit – Science 10

2. Specific Heat Capacity can be thought of as a measure of how much energy (in the form of heat) is needed to warm the substance up. Consider This: Water has a relatively large heat capacity. It takes a lot of energy to raise the temperature of water. This means that unlike other substances, water can absorb a lot of the sun’s energy and it will not change it’s temperature dramatically. This also means that it loses energy relatively slow as well. Water’s high heat capacity allows it to moderate temperature. (Think about the graphing activity you did)

3. Specific Heat Capacity (C) of a substance is the amount of heat required to raise the temperature of 1g of the substance by 1 o C. The units of specific heat capacity are J o C -1 g -1. Sometimes the mass is expressed in kg so the units could also be J o C -1 g -1 or J C -1 kg -1 J = Joules, kJ = Kilojoules C = Degrees Celsius g/Kg = Grams or Kilograms

4. The amount of heat energy (Q) gained or lost by a substance = mass of substance (m) X specific heat capacity (C) X change in temperature (ΔT, T 2 – T 1 ) Q = m x C x ΔT The Equation

5. The table shows how much energy it takes to heat up some different substances. The small values show that not a lot of energy is needed to produce a temperature change, whereas the large values indicate a lot more energy is needed.

6. How much energy would be needed to heat 450 grams of copper metal from a temperature of 25.0ºC to a temperature of 75.0ºC? (The specific heat of copper at 25.0ºC is 0.385 J/g ºC.) Example #1

7. Solution: The change in temperature (ΔT) is: 75ºC - 25ºC = 50ºC Given mass, two temperatures, and a specific heat capacity, you have enough values to plug into the specific heat equation Q = m x C x ΔT and plugging in your values you get Q = (450 g) x (0.385 J/g ºC) x (50.0ºC) = 8700 J

8. Examples 1.What quantity of heat is required to raise the temperature of 450 grams of water from 15°C to 85°C? 2.Calculate the specific heat capacity of copper given that 204.75J of energy raises the temperature of 15g of copper from 25°C to 60°C 3.216J of energy is required to raise the temperature of aluminum from 15°C to 35°C. Calculate the mass of aluminum. (C = 0.90 J/°C x g)

9. Websites For Practice http://www.algebralab.org/practice/practice.aspx?file=A lgebra_SpecificHeatCapacity.xml http://www.algebralab.org/practice/practice.aspx?file=A lgebra_SpecificHeatCapacity.xml http://www.kentchemistry.com/links/Energy/SpecificHea t.htm http://www.kentchemistry.com/links/Energy/SpecificHea t.htm