To plot the calibration curve, you need to prepare iron solutions with known concentrations and measure their absorbance. You will obtain a standard iron solution containing[ 0.2500g/L] of pure iron. Pipet 25.00mL of this standard iron solution into a 500mL volumetric flask and dilute up to the mark with distilled water. Finally, you will pipet certain amounts of this diluted solution into different flasks.

How much of this diluted solution do you need to pipet to have 0.00mg of iron?

answers: to make sure that all of the broken pieces of tablet were added to the water, to allow for fair comparison of all three trials, with different particle sizes to avoid experimental error

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