A typical candy bar weights about 2 oz (1.00 oz = 28.4 g)?

Question

A typical candy bar weights about 2 oz (1.00 oz = 28.4 g)
(a) Assuming that a candy bar is 100% sugar and that 1.0 g of the sugar is equivalent to about 4.0 Calories of energy, calculate the energy (in kJ) contained in a typical candy bar.
in kJ?
(b) Assuming that your mass is 67 kg and you convert chemical potential energy to work with 100% efficiency, how high would you have to climb to work off the energy in a candy bar? (Potential energy = mass g height, where g = 9.8 m/s2.)
in m?

Answer 1

A 2oz candy bar made of 100% sugar has a mass of 56.8g.
Each gram of sugar = 4.0 Calories, so 56.8g of sugar = 227 Calories.

In chemistry, we typically use units of calories, however, the unit we use is 1000 times smaller than the nutritional unit of Calories. Therefore, 227 nutritional Calories = 227,000 calories.

Each calorie = 4.184 J, so there are 951,000 J = 951 kJ of energy in the candy bar.

Kinetic energy, E(J) = 1/2 x mass(kg) x acceleration due to gravity(m/s2) x height (meters).

951,000J = 1/2 x (67kg) x (9.8 m/s2) x height

height = 2900 meters to completely work off the candy bar