Textbook Question
A 70.0-kg person had a quarter-pound cheeseburger, french fries, and a chocolate shake. (3.5) d. Using TABLE3.10, determine the number of hours of running needed to burn off the kilocalories in this meal.
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3. Matter and Energy
Nature of Energy
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An energy efficient refrigerator uses 780 kWh of electrical energy per year. How many kilocalories of electricity does it use in three years?
A
2.0 x 105 kcal
B
8.3 x 105 kcal
C
2.0 x 106 kcal
D
8.3 x 106 kcal
Verified step by step guidance1
Understand the conversion factor: 1 kilowatt-hour (kWh) is equivalent to 860 kilocalories (kcal).
Calculate the total energy consumption in kilowatt-hours for three years by multiplying the annual consumption by three: 780 kWh/year * 3 years.
Convert the total energy consumption from kilowatt-hours to kilocalories using the conversion factor: Total kWh * 860 kcal/kWh.
Express the result in scientific notation to match the options provided.
Compare the calculated value with the given options to determine the correct answer.
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