Do you think it is more useful to have the percent by mass of water in hydrate or the percentage composition, assuming that you know the formula for the associated dehydrated compound?
Can someone please explain what's the meaning of this question, I'm confuse. Thanks!
I believe would rather have the percent by mass in the hydrate if I know the formula of the dehydrated material. For example, if I know Na2SO4.xH2O is 55.9% H2O, then I know Na2SO4 is 44.1%.
I can take 100 g sample which gives
44.1 g Na2SO4 or 44.1/142 = 0.310 mols Na2SO4.
55.9 g H2O or 55.9/18 = 3.10 mols H2O
which is clearly 1 mol Na2SO4 to 10 mols H2O for the formula of Na2SO4.10H2O
I think the question is asking
a. If you know the formula is CuSO4 for the dehydrate, would you rather have the % H2O (as my calculation above) for you to determine the formula of the hydrate
OR
b. would you rather have the percent composition; i.e.,
%Cu
%S
%O
%H
I think if you choose b you must find a way to apportion the %O between the SO4 part and the H2O part. That can be done, of course, knowing the formula of the dehydrate; but I think a is the simpler method.
I already computed for the mass and moles of the hydrated salt which is CuSO4 .5H2O,
I just don't understand the question, whether i will choose which method then explain why??
Well, it seems like you've stumbled upon a chemistry question! Let me break it down for you in a fun and humorous way.
Imagine you have a hydrated compound, which means it has water molecules trapped within its structure like a secret hiding spot. Now, chemists are all about knowing the nitty-gritty details, so they want to find out two things:
1. The percent by mass of water: This is like knowing how much water your sneakers have soaked up after jumping in a puddle. It helps us understand the hydration level of the compound. Too much water? It might be a soggy mess!
2. The percentage composition: Now this is like figuring out the ingredients in your favorite pizza. We want to know the exact proportions of all the atoms present in the compound, including those sneaky water molecules.
So, to answer your question, both the percent by mass of water and the percentage composition are useful. They give chemists insight into the properties and behavior of the compound.
I hope that brings a smile to your face and clears up the confusion! Chemistry can be quite the clown sometimes, but it's always fun to unravel its mysteries.
Certainly! This question is referring to the analysis of hydrates, which are compounds that contain water molecules as part of their crystal structure. Hydrates have a specific ratio of water molecules to the anhydrous (dehydrated) compound. For example, the hydrate of copper sulfate (CuSO4) has the formula CuSO4·5H2O, which means it contains 5 water molecules for every CuSO4 unit.
Now, when analyzing a hydrate, there are two ways to express the amount of water present: percent by mass of water in the hydrate and percentage composition.
1. Percent by mass of water in the hydrate: This value represents the mass of water as a percentage of the total mass of the hydrate. It is calculated by dividing the mass of water by the mass of the hydrate and multiplying by 100. This value tells you how much water is present in the hydrate by mass.
2. Percentage composition: The percentage composition represents the relative contribution of each element in the hydrate's formula. For example, in CuSO4·5H2O, the percentage composition of water would be calculated by dividing the molar mass of water by the molar mass of the entire compound (hydrate) and multiplying by 100. This value tells you the proportion of each element in the hydrate's formula.
Both the percent by mass of water in the hydrate and the percentage composition provide different information. The percent by mass of water in the hydrate tells you about the mass of water in relation to the entire hydrate, whereas the percentage composition tells you the proportion of each element in the hydrate's formula. Which one is more useful will depend on the specific context or purpose of your analysis.
I hope this explanation clarifies the question for you!