Lab Analysis: Calorimetry

Heat is either released or absorbed during any chemical reaction. Calorimetry is the process of measuring this heat. In a calorimeter, a reaction occurs either directly in water or surrounded by a sealed water container. Changes in energy caused by the reaction are measured by measuring the change in temperature of the water in the calorimeter.

To measure the amount of energy in food, it can be burned in a calorimeter. When food is burned, it changes its mass and the water temperature in the calorimeter is raised as stored chemical energy in the food is converted to heat energy, thereby raising the temperature of the water.

Use the data provided in the table and the formulas shown in the equations below to complete the table and determine the energy content of the following foods.

Equations:

Calculations

• Heat calories = mass of water (g) change in temperature of the water (C) [Units = cal/(g)(C)]
• Kilocalories = Heat calories (cal)/1000 [Units = kcal]
• Energy yield = Kilocalories (kcal)/Grams of food (g) [Units = kcal/g]

Food tested	Starting Temperature (degrees Celsius)	Final Temperature (degrees Celsius)	Change in Temperature (degrees Celsius)	Mass of Water (g)	Heat Calories	Kcal	Mass of food	Energy yield
Marshmallow	23	60		100			1.0
Peanuts	23	67		100			1.0
Almonds	23	65		100			1.0
Chips	23	94		100			1.0
Popcorn	23	60		100			1.0

Compare the energy yield for the different foods you burned. (Complete sentences - compare and contrast based on the calculations...you must refer to data).

Why is the energy yield so much higher for peanuts and cheese puffs than it is for popcorn and marshmallows?