Suppose that 50.0 cm3 of 2.00 M hydrochloric acid are added to 4.00 grams of zinc metal.

What it the limiting reagent? How many grams of zinc are actually consumed? What is the concentration of the hydrochloric acid solution after the reaction has occurred? What mass of hydrogen will be produced?

A lot of questions. Do you need help with all of this or do you know how to do parts of it and want to check your answers? Post what work you've done.

Here is a link to an example stoichiometry problem I've posted. This is not a limiting reagent problem; however, you can make it a limiting reagent problem by working it twice to determine moles of the product formed and the smaller of the two values you obtain will be the correct value to use as the limiting reagent.
http://www.jiskha.com/science/chemistry/stoichiometry.html

To determine the limiting reagent, we need to compare the stoichiometry of the reaction to the given amounts of reactants.

First, we write the balanced equation for the reaction between hydrochloric acid (HCl) and zinc (Zn):

2HCl + Zn → ZnCl2 + H2

According to the balanced equation, the molar ratio between HCl and Zn is 2:1. This means that for every 2 moles of HCl, we need 1 mole of Zn.

1. To find the limiting reagent, we can use the given amounts of reactants and their molar masses.

The given amount of hydrochloric acid is 50.0 cm3, but we need to convert this to moles. The molar mass of HCl is 36.5 g/mol.
50.0 cm3 * (1 mL / 1 cm3) * (1 L / 1000 mL) * (2.00 mol / 1 L) = 0.100 mol HCl

The given amount of zinc is 4.00 grams. The molar mass of Zn is 65.4 g/mol.
4.00 g * (1 mol / 65.4 g) = 0.0611 mol Zn

Now we compare the moles of each reactant.
HCl: 0.100 mol
Zn: 0.0611 mol

Since the stoichiometry of the reaction is 2:1, we can see that there is less Zn (0.0611 mol) than required to fully react with the given amount of HCl (0.100 mol). Therefore, Zn is the limiting reagent.

2. To determine the actual grams of Zn consumed, we can use the molar mass of Zn.

0.0611 mol Zn * (65.4 g / 1 mol) = 4.00 g

So, 4.00 grams of zinc are actually consumed.

3. To find the concentration of the hydrochloric acid solution after the reaction, we need to calculate the moles and volume of the solution.

The reaction consumes 0.100 mol of HCl, which was initially at a volume of 50.0 cm3. Assuming the volume remains constant, the concentration after the reaction is:

0.100 mol / 50.0 cm3 * (1 L / 1000 cm3) = 0.0020 M HCl

Therefore, the concentration of the hydrochloric acid solution after the reaction is 0.0020 M.

4. Finally, to determine the mass of hydrogen produced, we need to use stoichiometry.

Since Zn is the limiting reagent, we can calculate the moles of H2 produced using the stoichiometric ratio of 1:1 between Zn and H2.

0.0611 mol Zn * (1 mol H2 / 1 mol Zn) * (2.02 g H2 / 1 mol) = 2.48 g

So, 2.48 grams of hydrogen will be produced.