Calculate the number of moles in these quantities.
1. 25.0 g KNO3
2. 5.4 x 102 g (NH4)2C2O4
moles = grams/molar mass.
To calculate the number of moles in a given quantity, we need to use the concept of molar mass. Molar mass refers to the mass of one mole of a substance and is expressed in grams per mole (g/mol). Here's how you can calculate the number of moles for each of the given quantities:
1. 25.0 g KNO3:
Step 1: Determine the molar mass of KNO3.
The molar mass of K (potassium) is approximately 39.10 g/mol.
The molar mass of N (nitrogen) is approximately 14.01 g/mol.
The molar mass of O (oxygen) is approximately 16.00 g/mol.
So, the molar mass of KNO3 is:
39.10 g/mol (K) + 14.01 g/mol (N) + (16.00 g/mol (O) x 3) = 101.11 g/mol
Step 2: Calculate the number of moles using the formula:
Number of moles = Mass (g) / Molar mass (g/mol)
Plugging in the values:
Number of moles = 25.0 g / 101.11 g/mol = 0.247 mol (rounded to three decimal places)
Therefore, there are approximately 0.247 moles of KNO3.
2. 5.4 x 102 g (NH4)2C2O4:
Step 1: Determine the molar mass of (NH4)2C2O4.
The molar mass of N (nitrogen) is approximately 14.01 g/mol.
The molar mass of H (hydrogen) is approximately 1.01 g/mol.
The molar mass of C (carbon) is approximately 12.01 g/mol.
The molar mass of O (oxygen) is approximately 16.00 g/mol.
So, the molar mass of (NH4)2C2O4 is:
2 (14.01 g/mol (N) + 4(1.01 g/mol (H))) + 2(12.01 g/mol (C) + 4(16.00 g/mol (O))) = 124.10 g/mol
Step 2: Calculate the number of moles using the formula:
Number of moles = Mass (g) / Molar mass (g/mol)
Plugging in the values:
Number of moles = 5.4 x 10^2 g / 124.10 g/mol ≈ 4.35 mol (rounded to two decimal places)
Therefore, there are approximately 4.35 moles of (NH4)2C2O4.