Calories from food Chapter 12

Calories Measurement of the energy content in a substance = heat Calorie = E require to raise the temperature of 1 gram of water 1*C Calorimeter is a device that measure the heat produced or absorbed during a process such as chemical reactions or combustion

calories calorie (small calorie) is the approximate amount of energy needed to raise the temperature of one gram of water by one degree Celsius Calorie (large calorie) kilogram calorie, dietary calorie, nutritionist's calorie or food calorie (symbol: Cal), 1 Cal equal to 1000 small calories This is a small unit so kcal is used 1000 cal = 1 kcal

calories q=(specific heat capacity) (mass) Δ T Δ T = change in T -q surrounding = q system why q surrounding + q system = q universe =0

Calories The SI unit for energy is Joule One small calorie is about 4.2 joules, and one large calorie is therefore 4.2 kilojoules. Sp Heat of water in calories is 1.00 cal/g*C Density of water =1

Experiment Going to burn a food product and measure the heat given off by measuring the temperature of water using a calorimeter Under the condition of the experiment the combustion is incomplete so the only part that burns is the fat The heat of the oil burning is all you are measuring

Heat Basically How many Calories (Kcal) from fat of the food. Ie.. 200ml of water in the soda can. Weight of chip is 0.882g before burning Weight of chip after 0.102g Temperature initial 27.8* C final 37.1*C

Calculations SmDT =q surrounding Calculte of q water = SmDT q=1.00cal/g*C)(200ml *1g/ml)( ) q=2004 kcal + because the water is gaining e and is endothermic. q surrounding =-q system q food= -q water or -2004kcal or Cal exothermic releases heat to system

Calculations Kcal or Cal in food, serving size is 20g Cal serving / 20 g = 2.00 Cal/ 0.790g Doing the math 50.7 Cal in the food per serving

Calculations % Error Label says 180 (50-180/180)*100 =72.2 %