What is the % composition by mass of water of crystallization in hydrated magnesium chloride?
The chemical formula for hydrated magnesium chloride is MgCl2·xH2O, where x represents the number of water molecules per formula unit. To find the % composition by mass of water of crystallization, we need to determine the molar mass of water and the molar mass of the entire compound.
The molar mass of water (H2O) is calculated by adding together the atomic masses of hydrogen (H) and oxygen (O):
Molar mass(H2O) = 2(1.008 g/mol) + 16.00 g/mol
= 18.016 g/mol
The molar mass of hydrated magnesium chloride (MgCl2·xH2O) is calculated by adding together the atomic masses of magnesium (Mg), chlorine (Cl), and water:
Molar mass(MgCl2·xH2O) = molar mass(Mg) + 2(molar mass(Cl)) + x(molar mass(H2O))
Given that the atomic masses are:
Molar mass(Mg) = 24.305 g/mol
Molar mass(Cl) = 35.453 g/mol
Substituting these values into the equation, we have:
Molar mass(MgCl2·xH2O) = 24.305 g/mol + 2(35.453 g/mol) + x(18.016 g/mol)
To find the % composition by mass of water of crystallization, we need to divide the molar mass of water by the molar mass of the entire compound and multiply by 100:
% composition by mass of water = (x(18.016 g/mol) / Molar mass(MgCl2·xH2O)) * 100
Therefore, the % composition by mass of water of crystallization in hydrated magnesium chloride can be calculated once the value of x is known.
To find the percent composition by mass of water of crystallization in hydrated magnesium chloride, we need to know the formula of the hydrated compound.
The general formula for hydrated compounds is: Compound·nH2O, where n represents the number of water molecules per formula unit of the compound.
For magnesium chloride, the chemical formula is MgCl2. However, in the hydrated form, it contains water molecules. Let's assume "x" represents the number of water molecules in hydrated magnesium chloride.
Therefore, the formula for hydrated magnesium chloride can be written as MgCl2·xH2O.
To find the percent composition by mass of water, we need to calculate the molar mass of water (H2O) and divide it by the molar mass of the hydrated compound (MgCl2·xH2O). We then multiply by 100 to get the percentage.
The molar mass of water (H2O) is calculated as follows:
- Atomic mass of hydrogen (H) = 1.01 g/mol
- Atomic mass of oxygen (O) = 16.00 g/mol
So, the molar mass of water is (2 × 1.01 g/mol) + (1 × 16.00 g/mol) = 18.02 g/mol.
Next, we need to calculate the molar mass of the hydrated compound (MgCl2·xH2O).
- Atomic mass of magnesium (Mg) = 24.31 g/mol
- Atomic mass of chlorine (Cl) = 35.45 g/mol
Adding the atomic masses, we get (1 × 24.31 g/mol) + (2 × 35.45 g/mol) = 95.21 g/mol.
Now, let's assume we know the value of x, which represents the number of water molecules. For example, if x = 6, then the formula is MgCl2·6H2O.
To find the mass percent, we divide the molar mass of water by the molar mass of the hydrated compound and multiply by 100:
(18.02 g/mol / 18.02 g/mol + (95.21 g/mol × 6)) × 100 = (18.02 g/mol / 617.46 g/mol) × 100 ≈ 2.92%.
So, if the formula of hydrated magnesium chloride is MgCl2·6H2O, the percent composition by mass of water of crystallization would be approximately 2.92%.
To determine the percentage composition by mass of water of crystallization in hydrated magnesium chloride, we need to know the chemical formula of the compound. Hydrated magnesium chloride is typically represented as MgCl2·xH2O, where "x" represents the number of water molecules attached to each magnesium chloride unit.
To find the % composition of water of crystallization, we need to calculate the ratio of the mass of the water molecules to the mass of the entire compound. This can be done by comparing the molar masses of water and the hydrated magnesium chloride.
1. Calculate the molar mass of water (H2O). The molar mass of hydrogen (H) is approximately 1 g/mol, and the molar mass of oxygen (O) is approximately 16 g/mol. Therefore, the molar mass of water is:
Molar mass of H2O = (2 * molar mass of H) + molar mass of O
= (2 * 1 g/mol) + 16 g/mol
= 18 g/mol
2. Determine the molar mass of hydrated magnesium chloride. The molar mass of magnesium (Mg) is approximately 24.3 g/mol, and the molar mass of chlorine (Cl) is approximately 35.5 g/mol. Based on the formula MgCl2·xH2O, the molar mass of hydrated magnesium chloride can be calculated as:
Molar mass of MgCl2·xH2O = (molar mass of Mg) + (2 * molar mass of Cl) + (x * molar mass of H2O)
= 24.3 g/mol + (2 * 35.5 g/mol) + (x * 18 g/mol)
3. Calculate the mass % of water of crystallization. The composition of water of crystallization is determined by dividing the molar mass of water by the molar mass of the entire compound, and then multiplying by 100 to obtain the percentage:
% composition = (Molar mass of H2O / Molar mass of MgCl2·xH2O) * 100
Substituting the values we obtained in steps 1 and 2:
% composition = (18 g/mol / (24.3 g/mol + 2 * 35.5 g/mol + x * 18 g/mol)) * 100
By calculating this expression, the % composition by mass of water of crystallization in hydrated magnesium chloride can be determined.