Department of Chemistry
Lab 3 Caloric Content of Food
Submitted by
Juan C. Delgado Román
Student # 0439722
Date Submitted: October 26, 2014
Date Performed: October 25, 2015
Lab Section: Chem-180
Course Instructor: Lea Stage Purpose
On this experiment we will learn how measure the energy content of 3 food items and become familiar with energy units: joules, and calories.
Procedure
For this laboratory exercise we use the following materials: Lighter, aluminum tray, metal fork, a piece of marshmallow, a walnut, and a potato chip, water, 100 ml beaker, burner stand, burner, digital scale, test tube clamp holder, thermometer.
I first weighted empty beaker, then beaker filled with 50ml of water. Recorded each weight and the difference was the water mass.
I placed the burner stand inside aluminum tray, then the beaker filled with water on top of burner stand. Measured the initial water temperature. I left the thermometer inside the beaker to measure water heat later.
I started with a marshmallow. I weighted alone first the marshmallow and the fork. Later weighted both together. I subtracted the total weight of fork + marshmallow to obtain the food item weight. I lit the marshmallow and once on fire, I placed it under the beaker and waited until burned completely. Then measured the final water temperature, weighted fork with remaining of the burnt marshmallow.
I repeated the same steps with a piece of walnut and a potato chip. Each time I would use fresh water, clean, dry out and allow the equipment to cool down.
A. Marshmallow: 7g
Metal Fork: 44.9g
Together: 56.2g
B. Walnut: 1.7g
Clamp: 26.1g
Together: 27.9g
C. Potato chip: 1.8g
Clamp: 26.1g
Together: 27.9g
I calculated with each food item: the change in temperature, ∆t= t final – t initial, mass of water in beaker, the heat energy gained by water, Q= ∆*m*cp, given the specific
References: & Pictures 1. Timberlake & Timberlake (2014), Basic Chemistry. Los Angeles: Pearson