How many grams of hydrogen gas are produced when 50.0 grams of zinc react with phosphoric acid, H3PO4 ?

Equation:3 Zn +2 H3PO4--->3 H2+ Zn3(PO4)2

Hmm.. the answer should be the limiting reaction

We already know the grams of Zn being used, but we have to find the grams of H3PO4 being used.

(50.0gZn) * (1moleZn/65.39gZn) * (97.9953gH3PO4/1moleZn) = 74.93g H3PO4

Now you have to find the limiting reaction

(50.0gZn) * (1moleZn/65.39gZn) * (3moleH2/3moleZn) * (2.016gH2/1moleH2) = 1.54g H2

Do that same thing with the H3PO4 using the mass

(74.93gH3PO4)*(1moleH3PO4/97.9953gH3PO4)*(3moleH2/2moleH3PO4)* (2.016gH2/1moleH2) = 2.312g H2

1.54g H2 will be produced. Sorry if I'm wrong, or my work is messy.

To Rob and Chopsticks.

Correct answer of 1.54 g H2 produced. Long way to get there.
First, Zn is the limiting reagent because there is no amount of H3PO4 given. Limiting reagent problems are those where BOTH reactants are given; then one must find the limiting reagent. Where just one reagent is given, it is always assumed that there is enough of the other, usually an excess, to use all of the grams of the reagent listed.
So moles Zn =
50 g x (1 mole Zn/65.39) = 0.7646.
Moles H2 = mols Zn x (3 moles H2/3 moles Zn) = 0.7646 x (1/1) = 0.7646 moles H2.
Grams H2 = 0.7646 moles H2 x (2.016 grams/1 mole H2) = 1.5415 which rounds to 1.54 to three significant figures. Technically, the 50 grams has only one s.f. (unless it was 50.0 or 50. and you just omitted the period or the other zero) but I doubt the instructor meant for you to round to 1 gram H2 gas.

To find the number of grams of hydrogen gas produced when 50.0 grams of zinc reacts with phosphoric acid, you need to use stoichiometry and the balanced chemical equation.

The balanced equation is: 3 Zn + 2 H3PO4 ---> 3 H2 + Zn3(PO4)2

From the balanced equation, we can see that for every 3 moles of zinc reacting, we get 3 moles of hydrogen gas. So, the ratio of moles of zinc to moles of hydrogen gas is 3:3, which simplifies to 1:1.

To find the moles of zinc, we can use its molar mass. The molar mass of zinc (Zn) is 65.38 g/mol.

Moles of zinc = Mass of zinc / Molar mass of zinc
Moles of zinc = 50.0 g / 65.38 g/mol
Moles of zinc ≈ 0.7643 mol

Since the ratio of moles of zinc to moles of hydrogen gas is 1:1, we have the same number of moles of hydrogen gas produced.

To find the grams of hydrogen gas, we can use the molar mass of hydrogen (H2), which is 2.02 g/mol.

Mass of hydrogen gas = Moles of hydrogen gas x Molar mass of hydrogen gas
Mass of hydrogen gas = 0.7643 mol x 2.02 g/mol
Mass of hydrogen gas ≈ 1.545 g

Therefore, approximately 1.545 grams of hydrogen gas are produced when 50.0 grams of zinc reacts with phosphoric acid.

To find the number of grams of hydrogen gas produced when 50.0 grams of zinc react with phosphoric acid, you need to use stoichiometry and the balanced chemical equation.

Step 1: Determine the molar mass of zinc (Zn) and hydrogen gas (H2).

The molar mass of Zn is 65.38 g/mol (from the periodic table), and the molar mass of H2 is 2.02 g/mol (again, from the periodic table).

Step 2: Convert the mass of zinc (given as 50.0 grams) into moles.

Using the formula:

moles = mass / molar mass

moles of Zn = 50.0 g / 65.38 g/mol = 0.764 moles of Zn

Step 3: Use the balanced chemical equation to determine the mole ratio between zinc and hydrogen gas.

From the balanced equation, you can see that 3 moles of Zn produce 3 moles of H2.

Step 4: Calculate the moles of hydrogen gas produced using the mole ratio.

moles of H2 = moles of Zn = 0.764 moles

Step 5: Convert the moles of hydrogen gas into grams.

Using the formula:

mass = moles x molar mass

mass of H2 = 0.764 moles x 2.02 g/mol = 1.545 grams of H2

Therefore, when 50.0 grams of zinc react with phosphoric acid, 1.545 grams of hydrogen gas are produced.