Chapter 3 Lecture Basic Chemistry Fourth Edition Chapter 3 Matter and Energy 3.6 Energy and Nutrition Learning Goal Use the energy values to calculate the kilojoules (kJ) or kilocalories (kcal) in a food. © 2014 Pearson Education, Inc.

Energy and Nutrition Carbohydrates are the body’s primary source of energy; however, when carbohydrate reserves are exhausted, fats and then proteins are used for energy. Primary Fuel Carbohydrates Fats Proteins

© 2014 Pearson Education, Inc. Energy and Nutrition On food labels, energy is shown as the nutritional Calorie, written with a capital C. In countries other than the United States, energy is shown in kilojoules (kJ). 1 Cal = 1000 cal 1 Cal = 1 kcal 1 Cal = 4184 J 1 Cal = kJ

© 2014 Pearson Education, Inc. Energy Food Values Foods are burned in a calorimeter to determine their energy values (kJ/g or kcal/g).

© 2014 Pearson Education, Inc. Energy values for the three food types are in kJ/g and kcal/g. Energy Food Values

© 2014 Pearson Education, Inc. Energy Food Values We can use energy values in Table 3.9 to calculate the energy from a food type when its mass is known.

© 2014 Pearson Education, Inc. Energy Content of Some Foods On the labels of packaged foods, the nutrition facts include the total Calories and kilojoules, and the grams of carbohydrate, fat, and protein per serving.

© 2014 Pearson Education, Inc. Guide to Calculating Energy from a Food

© 2014 Pearson Education, Inc. Sample Problem, Energy from a Food A hamburger sandwich contains 37 g of carbohydrate, 19 g of fat, and 23 g of protein. What is the total energy (kcal) from this food? Step 1Given37 g carbohydrate 19 g fat 23 g protein Needtotal kilojoules from hamburger

© 2014 Pearson Education, Inc. Sample Problem, Energy from a Food A hamburger sandwich contains 37 g of carbohydrate, 19 g of fat, and 23 g of protein. What is the total energy (kcal) from this food? Step 2Use the energy value for each food type and calculate.

© 2014 Pearson Education, Inc. Sample Problem, Energy from a Food A hamburger sandwich contains 37 g of carbohydrate, 19 g of fat, and 23 g of protein. What is the total energy (kcal) from this food? Step 3Add the energy from each food type to get total energy. Total energy = 150 kcal kcal + 90 kcal = 410 kcal

© 2014 Pearson Education, Inc. Chemistry Link to Health The amount of energy needed by a human each day depends on age, gender, and physical activity.

© 2014 Pearson Education, Inc. Chemistry Link to Health A person loses weight when his or her intake of calories is less than the calories used in a given day. Kilocalories burned per hour of walking are 200 swimming are 500 running are 750

© 2014 Pearson Education, Inc. Using the energy values per food type in Table 3.9, calculate the total energy (kcal) obtained from a diet that includes 52 g of carbohydrates, 6 g of fat, and 130 g protein. Learning Check

© 2014 Pearson Education, Inc. Solution Using the energy values per food type in Table 3.9, calculate the total energy (kcal) obtained from a diet that includes 52 g of carbohydrates, 6 g of fat, and 130 g protein. Step 1Given52 g carbohydrate 6 g fat 130 g protein Needtotal energy (kJ)

© 2014 Pearson Education, Inc. Solution Calculate the total energy (kcal) obtained from a diet that includes 52 g of carbohydrates, 6 g of fat, and 130 g protein. Step 2Use the energy value for each food type and calculate.

© 2014 Pearson Education, Inc. Solution Calculate the total energy (kcal) obtained from a diet that includes 52 g of carbohydrates, 6 g of fat and 130 g protein. Step 3Add the energy from each food type to calculate the total energy (kcal). Total energy value = 210 kcal + 40 kcal kcal = 770 kcal

© 2014 Pearson Education, Inc. Concept Map, Matter and Energy