Chemistry Question: Calculating Moles of Phosphoric Acid

How many moles of phosphoric acid are present in a sample containing 1.2 x 10^23 molecules?

Choose one:

A. 0.199 moles

B. 2.34 moles

C. 5.67 moles

Answer:

The correct answer is A. 0.199 moles.

To find the number of moles of phosphoric acid in the given sample, we can use the Avogadro's number and molar mass of the substance.

Explanation:

To calculate the number of moles in a given sample of a substance, we can use Avogadro's number and the molar mass of the substance. The molar mass of phosphoric acid (H₃PO₄) is calculated by summing the atomic masses of each element in the compound. The molar mass of H₃PO₄ is 98.00 g/mol.

Given that the sample contains 1.2 x 10^23 molecules, we can use the ratio:

1 mole of phosphoric acid = 6.02 x 10^23 molecules of phosphoric acid

Using this ratio, we can calculate:

Number of moles = (1.2 x 10^23 molecules) / (6.02 x 10^23 molecules/mol) = 0.199 moles