Molar Mass
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Molar Mass
Hello,
Does anyone know if it is safe to always assume 100 g when calculating for a molecular formula, in the case of the gram amount not being given ?
Does anyone know if it is safe to always assume 100 g when calculating for a molecular formula, in the case of the gram amount not being given ?
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Re: Molar Mass
Yes, unless there is an explicit amount given, always use 100g, as it makes percent composition problems much easier to solve.
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Re: Molar Mass
Yes, I believe it is always safe to use 100 g unless there is a specific amount given. This makes it easier as we can simply use the mass percent composition to solve for both molecular and empirical equations.
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Re: Molar Mass
Yes; we assume 100g because percentages are easy to calculate since the definition of percentage is a number/100. Molecular formula comes from empirical formula, and we calculate empirical formula from the ratio of atoms in a compound. It's easiest to find these ratios when you divide things by 100 and assume 100 grams. You can also assume 200 grams or 700 grams, but then calculating would require a lot of unnecessary effort.
Re: Molar Mass
Yes, this is acceptable, since you already know the molar mass percentages in this context.
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Re: Molar Mass
Yes! Dr. Lavelle told us to assume 100g if it is not previously stated. Hope this helps!
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Re: Molar Mass
Yes, if there is no specified amount, using 100g to find the molecular formula simplifies the process.
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Re: Molar Mass
Yes, because you already know that a percentage implies your given value /100, and if you're given a percentage mass composition, then each value would in turn be out of 100 g
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Re: Molar Mass
It should always be safe to use 100g, this is assuming that nothing else is previously stated. It also makes calculating percentage composition easier.
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Re: Molar Mass
Yes, you should always use 100 g when finding the molecular formula if the mass is not given! Dr. Lavelle mentioned this in his lecture as well, since using 100 g as the mass makes it a lot easier to calculate, especially if you are given the percent mass.
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Re: Molar Mass
We should always use 100g when there isn't a specific mass or value associated with the elements in the given problem.
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Re: Molar Mass
Honestly, you could use any number or value when determining this. However, we usually stick to 100 grams because it is the easiest when calculating. Instead of finding 26% of 52g of a compoud is made of carbon by mass, we would find 26% of 100. It just makes the whole calculation simpler.
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Re: Molar Mass
Yes, it is always safe to use 100g because it makes calculating the percentage easier when calculating the molar mass of elements.
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Re: Molar Mass
Yes, Professor actually encouraged this in the beginning of the quarter when we were learning how to find it
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