Suppose you were making 100.0 mL of a solution that is 0.040 M KCl. What mass of KCl should you weigh to make this solution?

mass = 0.2982 grams

Explanation:

Given that;

volume = 100.0 mL = 0.1 L

Molarity =0.040 M

Since Molarity =

(x) no of moles = 0.040 × 0.1

= 0.004 moles

Also; to calculate the  mass of KCl should you weigh to make this solution;

we have;

no of moles =

molar mass of KCl = 74.55 g/mol

∴

0.004 moles =

mass = 0.004 moles * 74.55

mass = 0.2982 grams

Hence, the mass of KCl should you weigh to make this solution is  0.2982 grams

atomic mass = 39

number of neutrons = 20

number of protons= 19

electronic configuration = 1s2 2s2 2p6 3s2 3p6 4s1

the number of electron in first shell = 2

number of electrons in n=3 shell = 8