Question

Sodium hydrogen sulfate is used as a cleaning agent and as a flux (a substance that promotes the fusing of metals and prevents the formation of oxides). One of the ways in which sodium hydrogen sulfate is manufactured is by reacting sodium dichromate, Na2Cr2O7, with sulfuric acid. This process also forms water and chromium(VI) oxide, CrO3.

a. Write a balanced equation for this reaction. (You do not need to include states.)

b. How many kilograms of chromium(VI) oxide are formed when 130.4 kg of sodium hydrogen sulfate is made?

c. What is the maximum mass of sodium hydrogen sulfate, NaHSO4, that can be formed from the reaction of 874.0 kg of sodium dichromate with 400.0 L of 18.0 M H2SO4?

Answer 1

a-

the reaction as stated

Na2Cr2O7 + H2SO4 = H2O + CrO3 + NaHSO4

balance

Na2Cr2O7 + H2SO4 = H2O + 2CrO3 + 2NaHSO4

b)

mass of CrO3 will form when

mass of NaHSO4 = 130.4 kg is formed

mol of NaHSO4 = 130.4/120.06 = 1.0861

ratio is

2:2

1.0861 mol of NaHSO4 = 1.0861 mol of CrO3

1.0861 kmol of CrO3 formed

mass = mol*MW = 1.0861*99.9943 =108.603 kg of CrO3 will form

c)

max NaHSO4 formed when

mol of Na2Cr2O7= mass/MW = 874/261.96754 = 3.336 = 3336

mol of H2SO4 = MV = 18*400 = 7200

since ratio 1:1

then, Na2Cr2O7 is limiting

Na2Cr2O7 --> 3336 mol

then

NaHSO4 produced = 2*3336 = 6672 mol of NaHSO4

mass = mol*MW = 6672*120.06 = 801040.32 g = 801.04 kg of NaHSO4