Q.3.26 - An Introduction to General, Organic, and Biological Chemistry

Question

Convert each of the following energy units:

a.$\text{ 8.1kcal to cal }$

b. $325\mathrm{J}\text{ to }\mathrm{KJ}$

c. $2550\mathrm{cal}\text{ to }\mathrm{KJ}$

d. $2.5\mathrm{kcal}\text{ to }\mathrm{J}$

Step-by-Step Solution

Answer

a. $8100\mathrm{cal}$

b. $0.325\mathrm{kJ}$

c. $10.7\mathrm{kJ}$

d. $10460\mathrm{J}$

Step 1: Given Information

The huge calorie, food calorie, or kilogram calorie was initially characterized as the need might have arisen to raise the temperature of one kilogram of water by one degree Celsius.

Step 2: Explanation

a. converting $8.1\mathrm{kcal}$ to cal,

Using $1\mathrm{kcal}=1000\mathrm{cal}$, Hence $8.1kcal$ is

$$\begin{gathered} =8.1\times 1000 \\ =8100cal \end{gathered}$$

b. converting $325\mathrm{J}\text{ to kJ}$,

Using $1.00\mathrm{kJ}=1000\mathrm{J}$, Hence $325J$ is

$$\begin{gathered} =\frac{325}{1000} \\ =0.325\mathrm{kJ} \end{gathered}$$

c. converting $2550\mathrm{cal}\text{ to }\mathrm{KJ}$,

Using $1\mathrm{kcal}=4.184\mathrm{kJ}$ and $1\mathrm{kcal}=1000\mathrm{cal}$ Hence $2550J$ is

$$\begin{gathered} =\frac{2550}{1000}\times 4.184 \\ =10.7J \end{gathered}$$

d. converting $2.5\mathrm{kcal}\text{ to }\mathrm{J}$,

Using $1k\mathrm{cal}=4184\mathrm{J}$, Hence $2.5kcal$is,

$$\begin{gathered} =2.5\times 4184 \\ =10460J \end{gathered}$$