Convert 23.4 kJ to calories
The Correct Answer and Explanation is:
To convert kilojoules (kJ) to calories (cal), we can use the conversion factor:
[
1 \, \text{kJ} = 0.239 \, \text{calories}
]
Therefore, to convert 23.4 kJ to calories, we multiply by 0.239:
[
23.4 \, \text{kJ} \times 0.239 \, \text{calories/kJ} = 5.59 \, \text{calories}
]
Explanation:
Energy is measured in various units, including joules (J) and calories (cal). These two units of energy are commonly used in the fields of chemistry and nutrition. In scientific contexts, energy is frequently measured in joules, while in nutrition, calories are the preferred unit for expressing energy content, such as in food.
The joule (J) is the SI (International System of Units) unit of energy, and one joule is defined as the energy transferred to an object when a force of one newton is applied over a distance of one meter. The calorie, on the other hand, is defined as the amount of heat energy required to raise the temperature of one gram of water by one degree Celsius at standard atmospheric pressure.
To convert between these two units, we use a standard conversion factor. Specifically, 1 kilojoule (kJ) is equal to 0.239 calories (cal). This conversion factor is based on the energy equivalence between the two units.
In the context of food and nutrition, understanding this conversion is important when reading food labels or assessing energy intake. For example, food energy is often given in kilocalories (kcal), which are sometimes simply referred to as “calories” in daily language. However, it is important to note that the calorie in this context is actually a kilocalorie (1 kcal = 1000 calories).
Thus, the energy content of 23.4 kJ is 5.59 calories, a small but important value when calculating energy from different sources.