How many grams of hydrogen gas be produced from the reaction of 3 g of magnesium with 4 g of hydrochloric acid. identify the limiting in excess reactants. Please help btw that's the exact question.

To find out how many grams of hydrogen gas are produced in the reaction between magnesium and hydrochloric acid, you first need to set up a balanced chemical equation for the reaction:

Mg + 2HCl -> MgCl2 + H2

From the balanced equation, you can see that 1 mole of magnesium reacts with 2 moles of hydrochloric acid to produce 1 mole of hydrogen gas.

1. Calculate the number of moles of magnesium and hydrochloric acid:

Moles of magnesium = mass of magnesium / molar mass of magnesium
Moles of magnesium = 3 g / 24.31 g/mol = 0.1234 mol

Moles of hydrochloric acid = mass of hydrochloric acid / molar mass of hydrochloric acid
Moles of hydrochloric acid = 4 g / (1.008 g/mol + 35.45 g/mol) = 0.1112 mol

2. Based on the balanced equation, you can see that 1 mole of magnesium reacts with 2 moles of hydrochloric acid to produce 1 mole of hydrogen gas.

Hence, you can determine the limiting and excess reactants by comparing the moles of magnesium and hydrochloric acid. The reactant that has fewer moles is the limiting reactant.

In this case, magnesium has fewer moles (0.1234 mol) compared to hydrochloric acid (0.1112 mol). Therefore, magnesium is the limiting reactant.

3. Calculate the moles of hydrogen produced based on the limiting reactant.

Since 1 mole of magnesium reacts to produce 1 mole of hydrogen gas, the moles of hydrogen gas produced would also be 0.1234 mol.

4. Finally, calculate the mass of hydrogen gas produced.

Grams of hydrogen gas = moles of hydrogen gas × molar mass of hydrogen gas
Grams of hydrogen gas = 0.1234 mol × 2.016 g/mol = 0.2485 g

Therefore, approximately 0.2485 grams of hydrogen gas would be produced.

To solve this problem, we need to follow a few steps:

Step 1: Write the balanced chemical equation for the reaction between magnesium and hydrochloric acid.

The balanced equation is:

Mg + 2HCl → MgCl2 + H2

This equation tells us that one mole of magnesium reacts with two moles of hydrochloric acid to produce one mole of magnesium chloride and one mole of hydrogen gas.

Step 2: Convert the given masses of magnesium and hydrochloric acid to moles.

Molar mass of magnesium (Mg) = 24.31 g/mol
Molar mass of hydrochloric acid (HCl) = 36.46 g/mol

Number of moles of magnesium = Mass of magnesium / Molar mass of magnesium
Number of moles of magnesium = 3 g / 24.31 g/mol = 0.1233 mol

Number of moles of hydrochloric acid = Mass of hydrochloric acid / Molar mass of hydrochloric acid
Number of moles of hydrochloric acid = 4 g / 36.46 g/mol = 0.1097 mol

Step 3: Determine the stoichiometric ratio between magnesium and hydrogen gas.

From the balanced equation, we can see that 1 mole of magnesium reacts to produce 1 mole of hydrogen gas. Therefore, the ratio is 1:1.

Step 4: Determine the limiting and excess reactants.

To determine the limiting reactant, we compare the moles of magnesium and hydrochloric acid using the stoichiometric ratio.

Since the ratio between magnesium and hydrogen gas is 1:1, we can directly compare the moles of hydrogen gas with the moles of hydrochloric acid.

Number of moles of hydrogen gas produced = Number of moles of hydrochloric acid = 0.1097 mol

So, 0.1097 moles of hydrogen gas will be produced.

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

Molar mass of hydrogen gas (H2) = 2.02 g/mol

Mass of hydrogen gas = Number of moles of hydrogen gas x Molar mass of hydrogen gas
Mass of hydrogen gas = 0.1097 mol x 2.02 g/mol = 0.2218 g

Therefore, from the given amounts of magnesium and hydrochloric acid, we can produce approximately 0.2218 grams of hydrogen gas.

The limiting reactant is hydrochloric acid because it is completely consumed, while magnesium is in excess.

Instead of posting the same kind of problem under different screen names (Kelsey, Lucy, Kristen), why don't you tell us what you don't understand and get it straight so you can do these yourself.