Question

If a sample of KF has a mass of 100.0 grams, how many moles of KF are present in the sample?

a. 1.000 mol
b. 1.721 mol
c. 0.5810 mol
d. 58.10 mol
e. 10.00 mol

Answer 1

In a sample of 100.0 grams KF we have 1.721 moles of KF present (option B is correct)

Step-by-step explanation:

Step 1: Data given

Mass of KF = 100.0 grams

Atomic mass of K= 39.10 g/mol

Atomic mass of F = 19.00 g/mol

Step 2: Calculate molar mass of KF

Molar mass KF = 39.10 + 19.00 = 58.10 g/mol

Step 3: Calculate moles of KF in the sample

Moles = mass / molar mass

Moles KF = 100.0 grams / 58.10 g/mol

Moles KF = 1.721 moles

In a sample of 100.0 grams KF we have 1.721 moles of KF present (option B is correct)

Answer 2

The answer to your question is the letter b. 1.721 moles

Step-by-step explanation:

Data

mass of KF = 100 g

The Number of moles = ?

Process

1.- Calculate the Molar mass of KF using the periodic table

K = 39.1

F = 19

Molar mass = 39.1 + 19

= 58.1 g

2.- Calculate the number of moles of KF

58.1 g of KF ------------------- 1 mol

100 g of KF ------------------- x

x = (100 x 1) / 58.1

x = 100 / 58.1

x = 1.721 moles