Question

2. What mass of CuSO4.5H2O is required to obtain 4.25 g of the anhydrous salt (CuSO4)? 3. The fertilizer known by the common name diammonium phosphate has the formula, (NH4)2HPO4. 2- N P -1 N-14.018 2:28.02 0-4 H -1.008x 9= 9,072 a. What is the mass percent of nitrogen in this compound? P. 30.97% 30.41 28.02gN 21.22% 0-16.00% 4:64 132.06 (NH4), 11Poy mas%. N = 732.06 b. 75.3 g of this compound contain how many grams of phosphorous?

answer # 2 & 3b

Answer 1

2)

Molar mass of CuSO4,
MM = 1*MM(Cu) + 1*MM(S) + 4*MM(O)
= 1*63.55 + 1*32.07 + 4*16.0
= 159.62 g/mol

mass of CuSO4 = 4.25 g
mol of CuSO4 = (mass)/(molar mass)
= 4.25/1.596*10^2
= 2.663*10^-2 mol


Balanced chemical equation is:
CuSO4.5H2O ---> CuSO4 + 5 H2O


According to balanced equation
mol of CuSO4.5H2O formed = moles of CuSO4
= 2.663*10^-2 mol


Molar mass of CuSO4.5H2O,
MM = 1*MM(Cu) + 1*MM(S) + 9*MM(O) + 10*MM(H)
= 1*63.55 + 1*32.07 + 9*16.0 + 10*1.008
= 249.7 g/mol


mass of CuSO4.5H2O = number of mol * molar mass
= 2.663*10^-2*2.497*10^2
= 6.648 g
Answer: 6.65 g

3)
b)

Molar mass of (NH4)2HPO4,
MM = 2*MM(N) + 9*MM(H) + 1*MM(P) + 4*MM(O)
= 2*14.01 + 9*1.008 + 1*30.97 + 4*16.0
= 132.062 g/mol


mass((NH4)2HPO4)= 75.3 g

use:
number of mol of (NH4)2HPO4,
n = mass of (NH4)2HPO4/molar mass of (NH4)2HPO4
=(75.3 g)/(1.321*10^2 g/mol)
= 0.5702 mol
This is number of moles of (NH4)2HPO4

one mole of (NH4)2HPO4 contains 1 moles of P
use:
number of moles of P = 1 * number of moles of (NH4)2HPO4
= 1 * 0.5702
= 0.5702

Molar mass of P = 30.97 g/mol

use:
mass of P,
m = number of mol * molar mass
= 0.5702 mol * 30.97 g/mol
= 17.66 g
Answer: 17.7 g