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Calories and Calorimetry. What is a calorie?. The calorie is an old term (Nicholas Clement in 1824) that was originally used as a unit of heat. It is used in some countries as a measure of food energy, however was replaced by the SI Unit, the Joule in 1867. Different definitions.
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What is a calorie? • The calorie is an old term (Nicholas Clement in 1824) that was originally used as a unit of heat. • It is used in some countries as a measure of food energy, however was replaced by the SI Unit, the Joule in 1867.
Different definitions • In chemistry the calorie (or gram calorie, unit cal) is the amount of energy required to raise the temperature of one gram of water by one degree Celsius. (4.184 Joules) • In food energy terms, the calorie (or kilogram calorie, unit c) is the amount of energy required to raise the temperature of one kilogram of water by one degree Celsius. (4 184 Joules or 4.184 kJ)
Calorimetry • Calorimetry is the science of measuring the heat of chemical reactions. • It was founded by Joseph Black, a Scottish physician, who was the first to distinguish between heat and temperature.
Bomb Calorimetry • A type of calorimetry where no work is done by the heat, so it equals the change in energy of the system. • The heat simply raises (or lowers) the temperature of the surroundings based on the reaction that is happening. • Next class, we will be burning a food item to see how many calories it has. • The best food items to bring in are carbohydrates since they burn the quickest usually.
Comparison of Calorimeters Scientific Ones Ones we will be using