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Activity 63: Measuring Calories Warm up: What would be the energy released when melting an ice cube if you had a 30°C temperature change in 70 mL of water? Quiz There will be a quiz on the last 3 activities in this unit (Activities 61-63) on Wednesday. Please remember to study and make a notecard! Unit D Test and Project Next class we are reviewing for the test and working on our project. ◦ Bring any materials you would need to work on the project! Your test is on Friday and the project is due next Tuesday. Unit D Missing Work If you have any missing work from Unit D, it needs to be in by the date of the test, no exceptions. Any “M” in NetClassroom will remain an “M” after you take the test! Activity 62 Analysis Questions Activity 62 In Case You Missed It Thermal energy always moves from hot to cold, causing changes in temperatures of both the hotter object and cooler object. Thermal energy use can be quantified by using the formula: Luminol Light Demo Where did the light energy come from? How is this different than the melting ice activity in Act. 62? How can we release the energy in a Cheeto? Activity 63: Measuring Calories Please open your books to page D53. Units of Energy Joule (J)- the SI (International System of Units) unit of energy measurement. ◦ One joule is the amount of energy required to exert a 1-newton force over a distance of 1 meter. Units of Energy Energy has many units of measurement, and another one of them is the calorie (cal). One calorie is the amount of heat energy required to raise 1 gram of water 1°C. ◦ One calorie is the water’s specific heat capacity. ◦ So what is the definition of specific heat capacity? One calorie is equal to 4.2 joules. Units of Energy The calorie, more so than the joule, is easily measured using water and is simple to calculate. ◦ This formula is for the specific heat capacity of water. ◦ For example, it takes 2 calories to increase the temperature of 2 grams of water 1°C or to heat 1 gram of water 2°C Units of Energy The nutritional Calorie (C) is a unit commonly used when measuring the amount of potential heat energy contained in a food. ◦ One Calorie =1,000 calories =1 kilocalorie (kcal) ◦ It is easier to write that a can of pop has 150 Calories compared to 150,000 calories. Activity 63: Measuring Calories Using a calorimeter, we can measure how many Calories are in a Cheeto. Knowing the formula for specific heat capacity: how do you think we will figure out the amount of Calories are in a Cheeto? Activity 63: Measuring Calories Each lab table has a calorimeter at it. This has: ◦ ◦ ◦ ◦ ◦ A hanger Aluminum foil A pop can A thermometer A fuel (Cheeto) stand Activity 63: Measuring Calories From the nutrition facts, we know that one Cheeto has about 7 Calories. What can account for the lower value of your result? Tonight’s homework Analysis questions #1-3 and #6. Study and prepare notecard for the quiz on Wednesday.