Question

a firm is considering purchasing two assets. Asset L will have a useful life of 15 years and cost $4 million

4. How many moles of hydrogen atoms are needed to make in 4.45 x 1022 formula units of (NH).PO.? Show all calculations. 5. How many atoms of nitrogen are found in 6.45 grams of (NH.), PO.? Show all calculations.

Answer 1

1)

1 molecule of (NH4)3PO4 has 12 hydrogen atoms.

So,

Number of H atoms = 12 * number of (NH4)3PO4

= 12 * 4.45*10^12

= 5.34*10^13

Answer: 5.34*10^13

2)

Molar mass of (NH4)3PO4,

MM = 3*MM(N) + 12*MM(H) + 1*MM(P) + 4*MM(O)

= 3*14.01 + 12*1.008 + 1*30.97 + 4*16.0

= 149.096 g/mol

mass((NH4)3PO4)= 6.45 g

use:

number of mol of (NH4)3PO4,

n = mass of (NH4)3PO4/molar mass of (NH4)3PO4

=(6.45 g)/(1.491*10^2 g/mol)

= 4.326*10^-2 mol

use:

number of molecules = number of mol * Avogadro’s number

number of molecules = 4.326*10^-2 * 6.022*10^23 molecules

number of molecules = 2.605*10^22 molecules

Count of each element in compound is:

{N=3, H=12, P=1, O=4}

Total number of N atoms in 1 molecule = 3

use:

number of atoms = number of molecules * Total number of atoms in 1 molecule

number of atoms = 2.605*10^22 * 3

number of atoms = 7.82*10^22

Answer: 7.82*10^22