# The nutritional label on the package indicates that a cookie contains 150 Calories. Express this...

## Question:

The nutritional label on the package indicates that a cookie contains 150 Calories. Express this value in kJ and in J.

## Calories to Joules:

To convert the calories in kilojoules, we'll use the general relation between them shown below:

• {eq}\displaystyle 1\textrm{ Calorie}=4.186\textrm{ kilojoules} {/eq}

After that, we'll multiply the obtained value by {eq}1000 {/eq} to get the result in joules.

• {eq}1\ kJ= 1000\ J {/eq}

The given calories in a cookie are:

{eq}q=150\textrm{ Calories} {/eq}

To convert the above unit, we'll multiply the above value by {eq}4.186 {/eq}.

{eq}\begin{align*} \displaystyle q&=150\textrm{ Calories}\times \frac{4.186\textrm{ kilojoules}}{1\textrm{ Calories}}\\ &=150\times 4.186\textrm{ kilojoules}\\ &=627.9\textrm{ kilojoules}\\ \end{align*} {/eq}

Again, we'll multiply the above value by {eq}1000 {/eq} and simplify it.

{eq}\begin{align*} \displaystyle q&=627.9\textrm{ kilojoules}\times \frac{1000\ \textrm{joules} }{1 \textrm{ kilojoules}}\\ &=627.9\times 1000\ \textrm{joules}\\ &=627900\ \textrm{J}\\ \end{align*} {/eq} 