1. List the species present at equilibrium in a solution with the following composition:

NH4Cl = 0.0200 mol/L NaOH = 0.0430 mol/L

H2SO4 = 0.0150 mol/L NaNO3 = 0.0100 mol/L

2. Write the n equations for n unknowns describing the equilibrium composition of

this system.

3. Make a spreadsheet and use Excel’s Solver function to determine the equilibrium

pH and concentrations of all species in this solution.

it’s previous models   because when i picked that son of a gun’s answer it was wrong look for previous models because they might make it a different letter  

as given the equation is

2al + 6 hcl > 2 alcl3 + 3 h2(g)

as per equation two moles of aluminum reacts with six moles of hcl to give two moles of alcl3 and three moles of hydrogen gas

given: three moles of al are present and 7 moles of hcl

for three moles of aluminum nine moles of hcl will be required

however as 7 moles of hcl are present so the limiting reagent is hcl

hcl is going to decide the number of moles of product formed

when six moles of hcl are present = 3 moles of h2 are formed

when one mole of hcl is present == 3/6 mole sof h2 will be formed

when 7 moles of hcl are present = 3 x 7/ 6 moles of h2 will be formed = 3.5 moles of h2