Question

How many moles are in 25.3 g of a sample of potassium nitrate (KNO3)?

Answer 1

To find the number of moles in 25.3 g of potassium nitrate (KNO3), divide the mass by the molar mass (101.1 g/mol) of KNO3 leading to 0.250 moles of KNO3.

Step-by-step explanation:

To calculate the number of moles in 25.3 g of potassium nitrate (KNO3), we must first determine its molar mass. The molar mass of KNO3 is the sum of the atomic masses of potassium (K), nitrogen (N), and three oxygen (O) atoms. The atomic mass of K is approximately 39.1 g/mol, of N is about 14.0 g/mol, and of O is 16.0 g/mol. Therefore, the molar mass of KNO3 is 39.1 + 14.0 + (3 × 16.0) = 101.1 g/mol.

Using this molar mass, we can convert the mass of KNO3 to moles by dividing the given mass by the molar mass:

Number of moles = mass in grams ÷ molar mass = 25.3 g ÷ 101.1 g/mol

Number of moles = 0.250 mol KNO3

Answer 2

25.3 g of KNO₃ contain 0.25 moles.

Step-by-step explanation:

Given data:

Number of moles of KNO₃ = ?

Mass of KNO₃ = 25.3 g

Solution:

Formula:

Number of moles = mass/ molar mass

Molar mass of KNO₃:

KNO₃ = 39 + 14+ 16×3

KNO₃ = 101 g/mol

Now we will put the values in formula.

Number of moles = 25.3 g/ 101 g/mol

Number of moles = 0.25 mol

Thus, 25.3 g of KNO₃ contain 0.25 moles.