Background Questions (5 points each = 10 points):
1. What happens to the molecules of the food that we eat during digestion?
2. What type of metabolism is this?
Background information:
In this lab we will attempt to set a variety of different types of food on fire and capture the heat energy that is given off. The heat energy from the burning comes form the energy stored in the chemical bonds of the food. The more energy in the bonds, the more heat the food will give off. We will capture the heat from the food in the water in a pop can by placing the burning food directly underneath the can. The basic premise of the lab is that the heat from the burning food will raise the temperature of the water in the …show more content…
By calculating the heat gained by the water we will figure out the energy stored in the food. Here’s how to calculate the energy gained by the water:
q = cm∆t
Where q is the heat gained by the water c is the specific heat of water (1 cal/g °c) m is the mass of the water in the can and ∆t is the change in temperature of the water
To calculate q, fill in the table below and multiply the values together.
DATA TABLE 2 (10 points)
Food
Specific heat of water
Mass of water in can
∆t of the water
Heat gained by water (cal) Divide by 1000
Kilocalories
(Calories)
1 cal/g °c
1000
1 cal/g °c
1000
1 cal/g °c
1000
1 cal/g °c
1000
1 cal/g °c
1000
1 cal/g °c
1000
1 cal/g °c …show more content…
Food scientists use the large calorie (Cal+ the energy needed to raise 1 liter of water one degree Celsius). To convert cal to Cal, just divide by 1,000.
Our next problem is that the food you burned did not have the same starting mass. That means that big pieces of food would release more energy than some of the smaller pieces of food even if they were really less energetic. To correct for this, we will calculate the energy per gram of each type of food. Fill out the table by dividing the kilocalories by the change in mass to calculate calories per gram:
Kilocalories ÷ ΔM
DATA TABLE 3 (10 points)
Food
Kilocalories
∆ mass
Calories per gram
Finally, you should calculate your percent error by comparing your value for the calories per gram with the experts. Look up at the board and use those calories per gram as the expected values and your calculated calories per gram as the observed value. Plug them into this formula and fill out the table below:
% error = (observed value – expected value) / expected value
DATA TABLE 4 (10 points)
Food
Observed
Expected
%