An antacid contains 200mg of aluminum hydroxide and 200 mg of magnesium hydroxide per capsule.
How many moles of aluminum hydroxide does each capsule contain?
What is the mass in milligrams of 0.0734 mole of magnesium hydroxide?
mols Al(OH)3 = grams Al(OH)3/molar mass Al(OH)3 = ?
To do part b just rearrange the equation above to grams = mols x molar mass and substitute the data for Mg(OH)2. Remember to convert grams to mg at the end.
To determine the number of moles of aluminum hydroxide in each capsule, you need to know the molar mass of aluminum hydroxide. The molar mass is the sum of the atomic masses of all the elements in the compound.
The atomic mass of aluminum (Al) is approximately 27 g/mol, and the atomic mass of oxygen (O) is approximately 16 g/mol. Hydrogen (H) has a much lower atomic mass, around 1 g/mol, so we can neglect its contribution for now.
The formula for aluminum hydroxide is Al(OH)3, which consists of one aluminum atom and three hydroxide (OH-) ions. The molar mass can be calculated as follows:
Molar mass of Al(OH)3 = (1 x Atomic mass of Al) + (3 x Atomic mass of O) + (3 x Atomic mass of H)
= (1 x 27 g/mol) + (3 x 16 g/mol) + (3 x 1 g/mol)
= 27 g/mol + 48 g/mol + 3 g/mol
= 78 g/mol
So, the molar mass of aluminum hydroxide is 78 g/mol.
Now, we need to convert the mass of aluminum hydroxide in each capsule to moles. The capsule contains 200 mg of aluminum hydroxide. To convert milligrams (mg) to grams (g), divide by 1000:
Mass of aluminum hydroxide in grams = 200 mg ÷ 1000
= 0.2 g
Then, use the molar mass of aluminum hydroxide to calculate the number of moles:
Number of moles of aluminum hydroxide = Mass of aluminum hydroxide ÷ Molar mass of aluminum hydroxide
= 0.2 g ÷ 78 g/mol
= 0.0026 moles
Therefore, each capsule contains approximately 0.0026 moles of aluminum hydroxide.
To determine the mass in milligrams of 0.0734 moles of magnesium hydroxide, we'll follow a similar process.
The formula for magnesium hydroxide is Mg(OH)2, which consists of one magnesium atom and two hydroxide ions. The molar mass can be calculated as:
Molar mass of Mg(OH)2 = (1 x Atomic mass of Mg) + (2 x Atomic mass of O) + (2 x Atomic mass of H)
= (1 x 24 g/mol) + (2 x 16 g/mol) + (2 x 1 g/mol)
= 24 g/mol + 32 g/mol + 2 g/mol
= 58 g/mol
The molar mass of magnesium hydroxide is 58 g/mol.
Now, to calculate the mass of 0.0734 moles of magnesium hydroxide, use the following formula:
Mass of magnesium hydroxide in grams = Number of moles of magnesium hydroxide x Molar mass of magnesium hydroxide
= 0.0734 moles x 58 g/mol
= 4.25 g
To convert grams to milligrams, multiply by 1000:
Mass of magnesium hydroxide in milligrams = 4.25 g x 1000
= 4250 mg
Therefore, the mass of 0.0734 moles of magnesium hydroxide is 4250 mg.