Multiple Choice
Which type of energy is primarily stored in a battery?
145
views
8. Thermochemistry
Nature of Energy
Multiple Choice
An energy efficient refrigerator uses 780 kWh of electrical energy per year. How many kilocalories of electricity does it use in three years?
A
2 x 105 kcal
B
8.3 x 105 kcal
C
2 x 106 kcal
D
8.3 x 106 kcal
Verified step by step guidance1
Identify the given information: the refrigerator uses 780 kWh of electrical energy per year, and we want to find the energy used in kilocalories over three years.
Calculate the total electrical energy used in three years by multiplying the yearly energy consumption by 3: \(\text{Total energy (kWh)} = 780 \times 3\).
Use the conversion factor between kilowatt-hours and kilocalories. Recall that 1 kWh is equivalent to approximately 860 kilocalories. Write this as: \(1 \text{ kWh} = 860 \text{ kcal}\).
Convert the total energy from kWh to kilocalories by multiplying the total kWh by the conversion factor: \(\text{Total energy (kcal)} = \text{Total energy (kWh)} \times 860\).
Express the final answer in scientific notation to match the format of the provided options.
Related Videos
Related Practice
