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Question Video: Converting the Amount of Kilocalories in a Chocolate Bar to Kilojoules Chemistry • 10th Grade

A chocolate bar is found to contain 228 kcal. What value is this in units of kilojoules? Give your answer to the nearest whole number.

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Video Transcript

A chocolate bar is found to contain 228 kilocalories. What value is this in units of kilojoules? Give your answer to the nearest whole number.

There are two common units used to measure energy: the joule, represented by uppercase J, and the calorie, represented by C-A-L. A joule is defined as the quantity of energy needed to raise the temperature of one gram of water by one divided by 4.184 degrees Celsius. A calorie is defined as the quantity of energy needed to raise the temperature of one gram of water by one degree Celsius. One calorie is equivalent to exactly 4.184 joules. In order to convert between calories and joules, we can use the following cycle. To convert from calories to joules, we multiply by 4.184. To convert from joules to calories, we divide by 4.184.

In this problem, we are given a measurement in kilocalories and must convert it to kilojoules. One kilojoule is 1000 joules, and one kilocalorie is 1000 calories.

Now we have all the information we need to perform our calculation. First, let’s multiply 228 kilocalories by 1000 calories per one kilocalorie. The units of kilocalories cancel, and the result is 228000 calories. Next, let’s convert calories to joules by multiplying by 4.184 joules per one calorie. The units calories cancel, and the result is 953952 joules. Finally , we can convert from joules to kilojoules by multiplying by one kilojoule per 1000 joules. The units joules cancel, and the answer is 953.952 kilojoules. Finally, after rounding our answer to the nearest whole number, we get 954 kilojoules.

In conclusion, 228 kilocalories is equivalent to 954 kilojoules.

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