Question

Determine the number of moles of the compound and determine the number of moles of each type of atom in 2.12 g of potassium bromide, KBr.

Answer 1

ANSWER

The number of moles of KBr is 0.0178 moles

The number of moles of K is 0.0178 moles

The number of moles of Br is 0.0178 moles

EXPLANATION

Given that;

The mass of the compound is 2.12 grams

The name of the compound is KBr

Follow the steps below to find the number of moles of the compound

Step 1; Apply the mole formula

$\text{ mole = }\frac{\text{ mass}}{\text{ molar mass}}$

The molar mass of KBr is 119.002 g/mol

$\begin{gathered} \text{ mole = }\frac{\text{ 2.12}}{\text{ 119.002}} \\ \text{ mole = 0.0178 moles} \end{gathered}$

The number of moles of KBr is 0.0178 moles

Part B

$\text{ KBr }\rightarrow\text{ K}^+\text{ + Br}^-$

In the above reaction, 1 mole of KBr is equivalent to 1 mole of K and 1 mole of Br

Recall, the Avogadro's number is 6.022 x 10^23

$\begin{gathered} \text{ For K atom} \\ \text{ 1 mole of potassium in KBr = 1 }\times\text{ number of moles of KBr} \\ \text{ Mole of potassium = 1 }\times\text{ 0.0178} \\ \text{ Mole of potassium = 0.0178 moles} \end{gathered}$$\begin{gathered} \text{ For Br} \\ \text{ mole of Br = 1 }\times\text{ mole of KBr} \\ \text{ Mole of Br = 1 }\times\text{ 0.0178} \\ \text{ Mole of Br = 0.0178 mole} \end{gathered}$