Hi, I am stuck on a couple questions in chemistry 11. The questions are
1. Calculate the number of moles of the anhydrous salt left behind
2. Calculate the number of moles of water removed by heat from your sample of hydrate.
3. Calculate the moles of water per mole of anhydrous salt.
My problem with the first question is I am not sure of how to find the amount of anhydrous salt left behind. The second one, I am not sure of how to calculate the number of moles of water that were removed by heat, and I am not sure of how to calculate the moles of water per mole of anhydrous salt :\
I have a data table.
Mass of empty crucible and lid = 30.93g
Mass of crucible, lid, and hydrate = 33.78g
Mass of hydrate = 2.85g
Mass of crucible, lid, and anhydrous salt = 32.39g
Mass of anhydrous salt = 1.46g
mass of water given off = 1.39g
Mass of one mole of anhydrous salt = 111.1g
The anhydrate that we used is CoCl2
Any help will be greatly appreciated.
I really don't understand your problem. You have all of the data you need to finish the problem.
1. 1.46g which is in the data part.
2. 1.39g which is in the data part.
3.Convert grams to moles.
1.46/molar mass H2O = ??
1.39/molar mass CoCl2 = ??
Now divide moles CoCl2 by itself (to get 1.00) and divide moles H2O by the same small number (about 0.011 or so), round the water to the nearest whole number and you will have x in CoCl2.xH2O.
mrs. lawsons chem ll? tfox?
Calculate the mass of sodium in 0.442g of salt
Sure! I can help you with these questions in chemistry. Let's tackle them one by one.
1. To calculate the number of moles of anhydrous salt left behind, you need to determine the number of moles of the anhydrous salt from its mass. Given that the mass of the anhydrous salt is 1.46g and the molar mass of the anhydrous salt is 111.1g/mol, you can use the formula:
Number of moles = Mass of anhydrous salt / Molar mass of anhydrous salt
Substituting the values, you get:
Number of moles = 1.46g / 111.1g/mol
2. To calculate the number of moles of water removed by heat from your sample of hydrate, you need to determine the mass of water that was given off. Given that the mass of water given off is 1.39g, you can use the formula:
Number of moles = Mass of water / Molar mass of water
The molar mass of water (H2O) is approximately 18.02g/mol, so substituting the values, you get:
Number of moles = 1.39g / 18.02g/mol
3. To calculate the moles of water per mole of anhydrous salt, you need to compare the number of moles of water removed (calculated in question 2) to the number of moles of anhydrous salt (calculated in question 1).
Number of moles of water per mole of anhydrous salt = (Number of moles of water) / (Number of moles of anhydrous salt)
Substituting the values, you get:
Number of moles of water per mole of anhydrous salt = (1.39g / 18.02g/mol) / (1.46g / 111.1g/mol)
Simplifying this expression will give you the answer.
Remember, when solving problems in chemistry, it's important to pay attention to the units and ensure they cancel out appropriately to give you the desired unit (in this case, moles).