Question

What is the mass, in grams, of 2.90×10−3 mol of ammonium phosphate?

Answer 1

0.432 g First, calculate the molar mass of ammonium phosphate by looking up the atomic mass of each element in ammonium phosphate Nitrogen = 14.0067 Hydrogen = 1.00794 Oxygen = 15.999 Phosphorus = 30.973762 Each molecule of ammonium phosphate has 3 Nitrogen, 12 Hydrogen, 1 Phosphorus, and 4 Oxygen atoms. Multiply the number of each type of atom with the atomic mass of each type of atom and add the results. m = 3 * 14.0067 + 12 * 1.00794 + 30.973762 + 4 * 15.999 m = 149.0851 So one mole of ammonium phosphate has a mass of 149.0851 g Since you have 2.90x10-3 moles, just multiply by the molar mass m = 2.90x10^-3 * 149.0851 = 0.432347 g Since you only have 3 significant figures for the number of moles, round the result to 3 significant figures giving 0.432 g

Answer 2

The mass, in grams, of 2.90 x 10^-3 moles of Ammonium phosphate is 0.432 g.

Further Explanation:

Moles, Atomic mass and Molar mass  

• 1 mole of a pure substance contains a mass that is equal to the relative atomic mass or molecular mass of the substance.
• Therefore; molar mass is given as grams per mole of a substance
• Molar mass of any element is equal to the atomic mass of that element in the unit of grams.

• Hence;

Molar mass = mass of a substance/ Number of moles

     g/mol = g /mole

• Thus:

• M = m/n; where M is the molar mass, m is the mass and n is the number of moles

• From this relationship we can therefore, calculate mass by multiplying the number of moles by molar mass of a substance.

That is; Mass = moles x molar mass

In this case;

We need to calculate the mass of 2.90 x 10^-3 moles of Ammonium phosphate

Step 1: Molar mass of Ammonium phosphate  

Molar mass of (NH4)3PO4 is given by;

 = 3 x 14.0067 + 12 x 1.00794 + 30.973762 + 4 x 15.999  

= 149.0851 g/mol (NH4)3PO4

Step 2: Mass of 2.90 x 10^-3 moles of Ammonium phosphate

1 mole of (NH4)3PO4 contains a mass of 149.0851 g

But;  

Mass = Molar mass x Number of moles  

         = 149.0851 g/mol x 2.90 x 10^-3

         = 0.432 g  

Therefore; 2.90 x 10^-3 moles of Ammonium phosphate contains a mass of 0.432 g

Keywords: Molar mass, moles

Learn more about:

• Relative atomic mass: brainly.com/question/4079113
• Moles calculation: brainly.com/question/4079113
• Molar mass: brainly.com/question/4079113

Level: High school

Subject: Chemistry

Topic: Moles

Sub-topic: Molar mass