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.
