Question

A sample of phosphonitrilic bromide, PNBr2, contains 2.01 mol of the compound. Determine the amount (in mol) of each element present and the number of atoms of each element present in the sample.

Answer 1

For 2.01 moles PNBr2 we have 1.21 *10^24 molecules

P = 1.21 *10^24 atoms

N = 1.21 *10^24 atoms

Br = 2.42*10^24 atoms

Step-by-step explanation:

Step 1: Data given

Number of moles of PNBr2 = 2.01 moles

Step 2: Calculate moles per element

For 1 mol PNBr2 we have 1 mol P, 1 mol N and 2 moles Br

For 2.01 moles PNBr2 we have:

P = 2.01 moles

N = 2.01 moles

Br = 2* 2.01 = 4.02 moles

Step 3: Calculate atoms of each element

For 2.01 moles PNBr2 we have 6.022 *10^23 * 2.01 = 1.21 *10^24 molecules

P = 2.01 moles = 6.022 *10^23 * 2.01 = 1.21 *10^24 atoms

N = 2.01 moles = 6.022 *10^23 * 2.01 = 1.21 *10^24 atoms

Br = 4.02 moles = 6.022 *10^23 * 4.02 = 2.42*10^24 atoms

Answer 2

2.01 moles of P → 1.21×10²⁴ atoms

2.01 moles of N → 1.21×10²⁴ atoms

4.02 moles of Br → 2.42×10²⁴ atoms

Step-by-step explanation:

We begin from this relation:

1 mol of PNBr₂ has 1 mol of P, 1 mol of N and 2 moles of Br

Then 2.01 moles of PNBr₂ will have:

2.01 moles of P

2.01 moles of N

4.02 moles of Br

To determine the number of atoms, we use the relation:

1 mol has NA (6.02×10²³) atoms

Then: 2.01 moles of P will have (2.01 . NA) = 1.21×10²⁴ atoms

2.01 moles of N (2.01 . NA) = 1.21×10²⁴ atoms

4.02 moles of Br (4.02 . NA) = 2.42×10²⁴ atoms