A sample of Manganese (II) Chloride has a mass of 19.8 grams before heating, and 12.6 grams after heating until all the water is driven out. Based on this information, how many water molecules were attached to each molecule of Manganese (II) Chloride?
19.8-12.6 = g H2O evolv3d = 7.2 g.
12.6/molar mass MnCl2 =
12.6/125.8 = 0.1 mole MnCl2
7.2/18 = 0.4 mol H2O
This is a ratio of 1 MnCl2 to 4 H2O so the formula is
MnCl2*4H2O
To determine the number of water molecules attached to each molecule of Manganese (II) Chloride, you'll need to calculate the mass of water lost during heating.
1. Calculate the mass of water lost:
Mass of water lost = Mass before heating - Mass after heating
= 19.8 grams - 12.6 grams
= 7.2 grams
2. Convert the mass of water lost to moles:
Moles of water lost = Mass of water lost / molar mass of water
= 7.2 grams / 18.01528 grams/mol (molar mass of water)
≈ 0.3997 mol
3. Determine the number of water molecules using Avogadro's number:
Number of water molecules = Moles of water lost * Avogadro's number
= 0.3997 mol * 6.022 × 10^23 molecules/mol
≈ 2.405 × 10^23 water molecules
Therefore, there were approximately 2.405 × 10^23 water molecules attached to each molecule of Manganese (II) Chloride.
To determine the number of water molecules attached to each molecule of Manganese (II) Chloride, we need to find the number of moles of both substances and compare their ratios.
First, we need to calculate the number of moles of Manganese (II) Chloride before and after heating.
The molar mass of Manganese (II) Chloride (MnCl2) is:
Molar mass of Mn = 54.94 g/mol
Molar mass of Cl = 35.45 g/mol
So, the molar mass of MnCl2 = 54.94 + (2 * 35.45) = 125.84 g/mol
Number of moles of MnCl2 before heating = mass of MnCl2 before heating / molar mass of MnCl2
Number of moles of MnCl2 before heating = 19.8 g / 125.84 g/mol = 0.157 moles
Number of moles of MnCl2 after heating = mass of MnCl2 after heating / molar mass of MnCl2
Number of moles of MnCl2 after heating = 12.6 g / 125.84 g/mol = 0.100 moles
The difference in moles of MnCl2 before and after heating corresponds to the number of moles of water that were driven out during heating.
Difference in moles = moles of MnCl2 before heating - moles of MnCl2 after heating
Difference in moles = 0.157 moles - 0.100 moles = 0.057 moles
Now, we know that for each molecule of MnCl2, there are 1 mole of water molecules attached. Therefore, the number of water molecules attached to each molecule of MnCl2 can be calculated as:
Number of water molecules = number of moles of water / number of moles of MnCl2
Number of water molecules = 0.057 moles / 0.100 moles = 0.57 water molecules
Since we cannot have a fraction of a water molecule, we round the result to the nearest whole number:
Number of water molecules attached to each molecule of Manganese (II) Chloride = 1 water molecule (rounded)