Question

the ionization potential of lithium is 520 kj/mole. the energy required to convert 70 mg of lithium atoms in gaseous state into li+ ions is

Answer 1

molar mass of li=6

70 mg of li= 70*1/1000=0.7g

therefore

0.7*1/6=0.1

Li+= 520 kj/mol

li= 0.1* 520=5.2 kj

answer

Answer 2

Answer: The amount of energy required for the given amount of lithium is 5.2 kJ

Explanation:

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

Given mass of lithium = 70 mg = 0.070 g     (Conversion factor:  1 g = 1000 mg)

Molar mass of lithium = 7 g/mol

Putting values in above equation, we get:

$\text{Moles of lithium}=\frac{0.070g}{7g/mol}=0.01mol$

We are given:

Ionization potential of lithium = 520 kJ/mol

As, 1 mole of lithium requires 520 kJ amount of energy to convert into its ions.

So, 0.01 moles of lithium will require = $\frac{520kJ}{1mol}\times 0.01mol=5.2kJ$ amount of energy to convert into its ions.

Hence, the amount of energy required for the given amount of lithium is 5.2 kJ