Question

What is the kinetic energy, in joules, of a molecule of carbon tetrachloride moving at a speed of 255 m s–1 (use the appropriate prefix to avoid exponential notation)?

Answer 1

Answer:

The kinetic energy of a molecule of carbon tetrachloride is 8.29 zJ.

       

Explanation:

The kinetic energy of a molecule of carbon tetrachloride is given by:

$K = \frac{1}{2}mv^{2}$

Where:

m: is the mass

v: is the speed = 255 m/s                            

To find the mass we need to find the molar mass for CCl₄, and use the Avogadro's number, knowing that in 1 mol of carbon tetrachloride we have 6.022x10²³ molecules:

A (C) = 12.011 g/mol

A (Cl) = 35.45 g/mol

The molar mass (M) of CCl₄ is:

$M = A (C) + 4*A (Cl) = 12.011 g/mol + 4*35.45 g/mol = 153.81 g/mol$

Now, the mass of 1 molecule of CCl₄ is:

$m = 153.81 \frac{g}{mol}*\frac{1 mol}{6.022 \cdot 10^{23} molecules} = 2.55 \cdot 10^{-22} g = 2.55 \cdot 10^{-25} kg$

Finally, the kinetic energy of a molecule of carbon tetrachloride is:

$K = \frac{1}{2}mv^{2} = \frac{1}{2}2.55 \cdot 10^{-25} kg*(255 m/s)^{2} = 8.29 zJ$

Therefore, the kinetic energy of a molecule of carbon tetrachloride is 8.29 zeptoJoule.

I hope it helps you!