2.5grams of pecan nut was turned to heat up 100grams of water at 24 degrees Celsius. The final temperature after all the pecan oil in the nut was completely consumed was 70 degrees Celsius. Calculate the (a) energy released by the 2.5 gram pecan in calories and (b) the food calories present in 1gram of pecan.
Lorena -- Please learn the difference between a school subject and a school!!
There is a difference between turning and burning pecans.
The water heats up by 46 degrees due to the burning. Heat added to the water is 100*46 = 4600 calories or 4.6 "food" Calories. That is 1.8 food Calories per gram. That number is much too low.
To calculate the energy released by the 2.5 grams of pecan in calories, we need to use the formula:
Q = mcΔT
Where:
Q = energy released (in calories)
m = mass of water (in grams)
c = specific heat capacity of water (1 calorie/gram °C)
ΔT = change in temperature (final temperature - initial temperature)
In this case:
m = 100 grams (mass of water)
c = 1 calorie/gram °C (specific heat capacity of water)
ΔT = 70°C - 24°C = 46°C
Substituting these values into the formula, we have:
Q = 100 grams * 1 calorie/gram °C * 46°C
Q = 4600 calories
Therefore, the energy released by the 2.5 grams of pecan is 4600 calories.
To calculate the food calories present in 1 gram of pecan, we need to divide the energy released by the mass of the pecan:
Food calories per gram = energy released (in calories) / mass of pecan (in grams)
In this case:
Energy released = 4600 calories
Mass of pecan = 2.5 grams
Substituting these values into the formula, we have:
Food calories per gram = 4600 calories / 2.5 grams
Food calories per gram = 1840 calories/gram
Therefore, there are 1840 food calories in 1 gram of pecan.