The Joule (J) Is The SI Unit Of Energy. 1 Calorie (Cal) = 4.184 J J Cal KJ 558 109 0.492 The Joule (J) Is The SI Unit Of Energy. 1 Calorie (Cal) = 4.184 J; 1 Kcal = 1000 Cal J KJ Kcal 507 Egress 0.739 0.200 A List Of The Calorie Content Of Foods Indicates That A Piece Of Lemon Meringue Pie Contains 319 Calories. Express This Value In KJ And In J. The
The Correct Answer and Explanation is :
To convert the calorie content of the lemon meringue pie into joules (J) and kilojoules (kJ), we need to use the conversion factor between calories (Cal) and joules. The conversion factors are:
1 calorie (Cal) = 4.184 joules (J)
1 kilocalorie (kcal) = 1000 calories (Cal)
Given:
- The calorie content of the lemon meringue pie is 319 Calories (Cal).
Step 1: Converting Calories to Joules
We can convert the calories into joules using the formula: Energy in joules (J)=Energy in calories (Cal)×4.184\text{Energy in joules (J)} = \text{Energy in calories (Cal)} \times 4.184
Substituting the values: Energy in joules=319 Cal×4.184 J/Cal=1339.296 J\text{Energy in joules} = 319 \, \text{Cal} \times 4.184 \, \text{J/Cal} = 1339.296 \, \text{J}
Therefore, the energy content of the lemon meringue pie in joules is 1339.296 J.
Step 2: Converting Calories to Kilojoules
To convert the energy into kilojoules (kJ), we use the conversion factor: Energy in kilojoules (kJ)=Energy in joules (J)÷1000\text{Energy in kilojoules (kJ)} = \text{Energy in joules (J)} \div 1000
Substituting the value: Energy in kilojoules=1339.296 J÷1000=1.339 kJ\text{Energy in kilojoules} = 1339.296 \, \text{J} \div 1000 = 1.339 \, \text{kJ}
Therefore, the energy content of the pie in kilojoules is 1.339 kJ.
Explanation
Energy in foods is typically measured in calories (Cal) or kilocalories (kcal). A calorie is a unit of heat energy and represents the amount of heat required to raise the temperature of 1 gram of water by 1°C. The joule (J) is the SI (International System of Units) unit of energy and is more commonly used in scientific contexts. The conversion from calories to joules involves multiplying by the factor 4.184 J/Cal. Since 1 kilocalorie is 1000 calories, it follows that 1 Calorie is 1/1000th of a kilocalorie.
In summary, the 319 Calories in the lemon meringue pie are equivalent to 1339.296 joules (J) or 1.339 kilojoules (kJ), which are the energy content values in both units of measurement.