1. Chapter 3: Matter & Energy
DE CHEMISTRY: King William High School
Chapter 3: Matter & Energy

2. 1. Classification of Matter
Pure substances (elements & compounds) have definite composition
Mixture is two or more different substances physically combined
Homogeneous mixtures – uniform throughout (solution)
Heterogeneous mixtures – NOT uniform

3. 2. States of Matter Solid – definite shape and volume
Liquid – definite volume; NOT shape
Gas – neither definite shape nor volume

4. Properties of Matter Physical properties – shape, color, MP, BP, FP
Chemical properties – describe a substance changing into something new (metal rusting)

5. Physical change – changes in state (melting, freezing, etc.)
Changes of Matter
Physical change – changes in state (melting, freezing, etc.)
Chemical change – changes into a new substance

6. 4. Energy Kinetic v. potential
Heat- energy associated with the motion of molecules
Units (Joule and calorie)
1 cal = J
1Cal = 1 kcal = 1000 cal
Convert 6.2 x 102 J to cal and Cal.

7. 5. Energy content for food
Carbohydrate = 4kcal/g
Fat = 9 kcal/g
Protein = 4 kcal/g
EX: You eat a meal that has 37 g of carbs, 19 g of fat and 23 g of protein. How many Calories did you intake?

8. 6. Specific Heat Q = cmDT Table 3.11 on page 74
How much heat is released when 7 g of copper is cooled from 20oC to 10oC?

9. 7. Changes in State Melting and freezing points
Heat of fusion – energy needed to melt a substance
Heat = mass x heat of fusion
How much heat will be absorbed from 26.0 g of ice in a soft drink at 0oC if the heat of fusion = 334 J/g?

10. More…
Heat of vaporization – energy required to turn a liquid to a gas at its BP
Heat = mass x heat of vap.

11. Heating Curves
Page 81

12. Cooling curves
Opposite of heating curves

13. Combining energy calculations
How much energy is needed to heat 100 g of diethyl ether from 5oC to its boiling point and boil it? The specific heat is 2.33 J/goC. The heat of vaporization is 357 J/g.