A17.8g mass of magnesium is added in a solution of hydrochloric acid. What mass of magnesium chloride will be formed?

To find the mass of magnesium chloride formed, we first need to determine the chemical reaction that occurs when magnesium reacts with hydrochloric acid. The balanced chemical equation for this reaction is:

Mg + 2HCl -> MgCl2 + H2

From the equation, we can see that 1 mole of magnesium reacts with 2 moles of hydrochloric acid to form 1 mole of magnesium chloride. The molar mass of magnesium is 24.31 g/mol and the molar mass of magnesium chloride is 95.21 g/mol.

First, we need to calculate the number of moles of magnesium in 17.8g:

Number of moles = Mass / Molar mass
Number of moles = 17.8g / 24.31 g/mol
Number of moles = 0.733 moles

Since 1 mole of magnesium reacts with 1 mole of magnesium chloride, the mass of magnesium chloride formed will be equal to the molar mass of magnesium chloride multiplied by the number of moles of magnesium:

Mass of magnesium chloride = Number of moles * Molar mass of MgCl2
Mass of magnesium chloride = 0.733 moles * 95.21 g/mol
Mass of magnesium chloride = 69.78g

Therefore, 69.78g of magnesium chloride will be formed when 17.8g of magnesium reacts with hydrochloric acid.

Step 1: Write the balanced chemical equation.

Mg + 2HCl → MgCl2 + H2

Step 2: Convert the mass of magnesium to moles.

17.8 g Mg × (1 mol Mg / 24.31 g Mg) = 0.732 mol Mg

Step 3: Use the stoichiometry of the balanced equation to determine the moles of magnesium chloride formed.

From the balanced equation, we see that 1 mol of Mg reacts with 1 mol of MgCl2. Therefore, 0.732 mol of Mg will react with 0.732 mol of MgCl2.

Step 4: Convert the moles of magnesium chloride to mass.

0.732 mol MgCl2 × (95.21 g MgCl2 / 1 mol MgCl2) = 69.6 g MgCl2

Therefore, 69.6 g of magnesium chloride will be formed.