A 5 mL dose of Milk of Magnesia contains 400 mg of magnesium hydroxide. What mass in grams of HCl can it neutralize? Balanced equation= Mg(OH)sub2 + 2HCl---> MgClsub2(aq) + 2Hsub2O
To determine the mass of HCl that can be neutralized by a 5 mL dose of Milk of Magnesia, we need to use stoichiometry and molar ratios.
First, we need to convert the volume of Milk of Magnesia from milliliters (mL) to liters (L). Since 1 L is equal to 1000 mL, we can convert the volume as follows:
5 mL = 5/1000 L
= 0.005 L
Next, we'll use the balanced equation to find the molar ratio between magnesium hydroxide (Mg(OH)2) and HCl. The equation provides the following ratio: 1 mole of Mg(OH)2 reacts with 2 moles of HCl.
From the given information, we know that there is 400 mg of magnesium hydroxide in 5 mL of Milk of Magnesia. To convert this to moles, we need to use the molar mass of Mg(OH)2.
The molar mass of Mg(OH)2 is calculated by adding up the atomic masses of each element:
Mg: 24.31 g/mol
O: 16.00 g/mol
H: 1.01 g/mol (2 hydrogen atoms)
Molar mass of Mg(OH)2 = (24.31 g/mol) + (16.00 g/mol + 1.01 g/mol + 1.01 g/mol)
= 58.33 g/mol
Now, we can calculate the number of moles of Mg(OH)2 in 400 mg using the formula:
moles = mass / molar mass
moles of Mg(OH)2 = 400 mg / 58.33 g/mol
= 0.00685 mol
Since the molar ratio between Mg(OH)2 and HCl is 1:2, the number of moles of HCl required to react with 0.00685 moles of Mg(OH)2 is:
moles of HCl = 2 * moles of Mg(OH)2
= 2 * 0.00685 mol
= 0.0137 mol
Finally, we need to convert the moles of HCl to grams using its molar mass. The molar mass of HCl is determined by adding the atomic masses of hydrogen and chlorine:
H: 1.01 g/mol
Cl: 35.45 g/mol
Molar mass of HCl = 1.01 g/mol + 35.45 g/mol
= 36.46 g/mol
mass of HCl = moles of HCl * molar mass of HCl
= 0.0137 mol * 36.46 g/mol
= 0.499 g
Therefore, a 5 mL dose of Milk of Magnesia can neutralize approximately 0.499 grams of HCl.