How many grams of KNO3 are present in 185 mL of a 2.50 M solution?

46.71g

Explanation:

First, we'll begin by calculating the number of mole of KNO3 present in the solution. This is illustrated below below:

Data obtained from the question:

Molarity = 2.50 M

Volume = 185 mL = 185/1000 = 0.185L

Mole =?

Molarity = mole /Volume

Mole = Molarity x Volume

Mole = 2.5 x 0.185

Mole = 0.4625 mole

Now we can obtain the mass of KNO3 as follow:

Molar Mass of KNO3 = 39 + 14 + (16x3) = 39 + 14 + 48 = 101g/mol

Number of mole of KNO3 = 0.4625 mole

Mass of KNO3 =?

Mass = number of mole x molar Mass

Mass of KNO3 = 0.4625 x 101

Mass of KNO3 = 46.71g

The person writes a coefficient of 2 in front of Fe2O3 but then writes a 4 for the number of iron (Fe) atoms. Explain this difference.

Explanation: