a 5.00g sample of a hydrate of barium chloride was heated, and only 4.30g of the anhydrous salt remained. what is the formula of the hydrate?
thanks!!
To find the formula of the hydrate, we need to determine the ratio of water molecules to the anhydrous salt.
Step 1: Calculate the mass of water lost.
Mass of water lost = Initial mass of hydrate - Mass of anhydrous salt
Mass of water lost = 5.00g - 4.30g
Mass of water lost = 0.70g
Step 2: Determine the number of moles of water lost.
Moles of water lost = Mass of water lost / molar mass of water
Molar mass of water (H2O) = 2 * molar mass of hydrogen (H) + 1 * molar mass of oxygen (O)
Molar mass of hydrogen (H) = 1.007g/mol
Molar mass of oxygen (O) = 15.999g/mol
Molar mass of water (H2O) = (2 * 1.007g/mol) + (16.00g/mol) = 18.015g/mol
Moles of water lost = 0.70g / 18.015g/mol
Step 3: Determine the moles of barium chloride.
Moles of barium chloride = Moles of anhydrous salt
Moles of anhydrous salt = Mass of anhydrous salt / molar mass of anhydrous salt
To find the molar mass of barium chloride (BaCl2), you can either refer to the periodic table or use online sources. The molar mass of barium (Ba) is approximately 137.33g/mol, and the molar mass of chlorine (Cl) is approximately 35.45g/mol.
Molar mass of barium chloride (BaCl2) = (1 * molar mass of barium (Ba)) + (2 * molar mass of chlorine (Cl))
Molar mass of barium chloride (BaCl2) = (1 * 137.33g/mol) + (2 * 35.45g/mol)
Molar mass of barium chloride (BaCl2) = 208.23g/mol
Moles of barium chloride = 4.30g / 208.23g/mol
Step 4: Find the ratio of moles between water and the anhydrous salt.
To find the ratio, we need to divide both the moles of water and the moles of anhydrous salt by the smallest value.
Moles of water / Moles of anhydrous salt = Ratio of water to anhydrous salt
Ratio of water to anhydrous salt = (0.70g / 18.015g/mol) / (4.30g / 208.23g/mol)
Step 5: Simplify the ratio and determine the formula of the hydrate.
To simplify the ratio, multiply both the numerator and the denominator by the denominator.
Ratio of water to anhydrous salt = (0.70g / 18.015g/mol) * (208.23g/mol / 4.30g)
Ratio of water to anhydrous salt = 32.66 / 4.30
Ratio of water to anhydrous salt = 7.587
Therefore, the formula of the hydrate is BaCl2·7.587H2O.
To determine the formula of the hydrate, we need to compare the mass of the water lost during heating to the mass of the anhydrous salt that remains.
First, let's find the mass of water lost during heating:
Mass of water lost = Mass of hydrate - Mass of anhydrous salt
= 5.00g - 4.30g
= 0.70g
The molar mass of water (H₂O) is approximately 18.02 g/mol.
To determine the number of moles of water lost, we can use the formula:
Number of moles = Mass / Molar mass
= 0.70g / 18.02 g/mol
≈ 0.0388 mol
To determine the molar ratio between the anhydrous salt and water, we can use the principle of stoichiometry. The number of moles of water lost is equal to the number of moles of water in one molecule of the hydrated compound.
By dividing the number of moles of water lost (0.0388 mol) by the lowest possible value, we can obtain the mole ratio between the anhydrous salt and water. In this case, since we want the lowest ratio, we divide it by itself:
0.0388 / 0.0388 = 1
The formula of the hydrate can be represented as:
BaCl₂ • xH₂O
Since the mole ratio is 1, x is 1, which means there is one water molecule in the formula. Therefore, the formula of the hydrate is BaCl₂ • H₂O.
how many moles of BaCl2 is in 4.3g?
how many moles of H2O is in .70g?
now look at the ratio. If there were 7 times as many moles of water as BaCl2, the formula would have been BaCl2.7H2O