Explanation:

1 calorie is equal to 4.18 joules.

Conversion Factors:
To understand why 1 calorie is equal to 4.18 joules, we need to understand the conversion factors between these units.

1 calorie:
A calorie is a unit of energy commonly used in nutrition and chemistry. It is defined as the amount of energy required to raise the temperature of 1 gram of water by 1 degree Celsius.

1 joule:
A joule is the SI unit of energy. It is defined as the amount of work done when a force of 1 newton is applied over a distance of 1 meter.

Conversion:
To convert between calories and joules, we can use the following conversion factor:

1 calorie = 4.18 joules

This conversion factor is derived from the specific heat capacity of water, which is approximately 4.18 joules/gram·°C.

When we multiply a value in calories by the conversion factor, we get the equivalent value in joules. Similarly, when we divide a value in joules by the conversion factor, we get the equivalent value in calories.

Example:
Let's say we have 100 calories and we want to convert it to joules. We can use the conversion factor as follows:

100 calories * 4.18 joules/calorie = 418 joules

So, 100 calories is equal to 418 joules.

Similarly, if we have 500 joules and we want to convert it to calories, we can use the conversion factor as follows:

500 joules / 4.18 joules/calorie = 119.61 calories

So, 500 joules is equal to 119.61 calories.

Conclusion:
In summary, 1 calorie is equal to 4.18 joules. This conversion factor is derived from the specific heat capacity of water.

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