1 Chapter 2Energy and Matter 2.2 Energy and Nutrition

2 Calorimeters A calorimeter is used to measure heat transfer. can be made with a coffee cup and a thermometer. indicates the heat lost by a sample indicates the heat gained by water.

3 Energy and Nutrition On food labels, energy is shown as the nutritional Calorie, written with a capital C. In countries other than the U.S., energy is shown in kilojoules (kJ). 1 Cal = 1000 calories 1 Cal = 1 kcal 1 Cal = 1000 cal 1 Cal = 4184 J 1 Cal = kJ

4 Caloric Food Values The caloric or energy values for foods indicate the number of kcal(Cal) provided by 1 g of each type of food. Carbohydrate: 4 kcal 1 g Fat (lipid): 9 kcal 1 g Protein: 4 kcal 1 g

5 Energy Values for Some Foods TABLE 2.2

6 Energy Requirements The amount of energy needed each day depends on age, sex, and physical activity. TABLE 2.3

7 A cup of whole milk contains 12 g of carbohydrate, 9.0 g of fat, and 5.0 g of protein. How many kcal (Cal) does a cup of milk contain? 1) 48 kcal (or Cal) 2) 81 kcal (or Cal) 3) 150 kcal (or Cal) Learning Check

8 A cup of whole milk contains 12 g of carbohydrate, 9.0 g of fat, and 5.0 g of protein. How many kcal (Cal) does a cup of milk contain? 3) 150 kcal (or Cal) 12 g carbohydrates x 4 kcal/g = 50 kcal (1 SF) 9.0 g fat x 9 kcal/g = 80 kcal (1 SF) 5.0 g protein x 4 kcal/g = 20 kcal (1 SF) 150 kcal Solution