Last Step of Calculating Molecular Formulas
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Last Step of Calculating Molecular Formulas
In the last step of calulating molecular formulas fo you multiply OR divide by a whole number?
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Re: Last Step of Calculating Molecular Formulas
In the last step, you multiply. Before that step, you find the molar mass of the empiral formula and divide that by the given mass of the molecule given (so given molar mass/mass of empirical formula), and whatever number you get from that, you would multiply that by the empirical formula in order to get the molecular formula. I'm not sure if this is what you were asking for, but I hope it still helps!
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Re: Last Step of Calculating Molecular Formulas
Hey! So once you get a rounded whole number by dividing the molecular mass by the mass of the empirical formula, I think you're supposed to multiply the empirical formula by that number.
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Re: Last Step of Calculating Molecular Formulas
In the last step, you would multiply. You would divide the sample's molar mass by the empirical formula's molar mass to find the ratio. You would then multiply the empirical formula by the ratio found, giving you the molecular formula.
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Re: Last Step of Calculating Molecular Formulas
Here's the simple steps to always remember !
To calculate the molecular formula we need its molar mass, so take your empirical formula and multiply by the mole of that respective element (example: if you have C3, multiply that 3 by the mole of carbon 12.01). Once you do that, you can add each of them up to get your total molar mass (g/mol). Next, divide the mass of the compound by the molar mass found to get the number which you will use to multiply it by those of your empirical formula to get the molecular formula !
To calculate the molecular formula we need its molar mass, so take your empirical formula and multiply by the mole of that respective element (example: if you have C3, multiply that 3 by the mole of carbon 12.01). Once you do that, you can add each of them up to get your total molar mass (g/mol). Next, divide the mass of the compound by the molar mass found to get the number which you will use to multiply it by those of your empirical formula to get the molecular formula !
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Re: Last Step of Calculating Molecular Formulas
Usually, if there are fractioned values in the formula, you would begin by dividing by the lowest value, and then afterwards multiplying the formula by a specific value so that all of the values in the formula are whole integers.
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Re: Last Step of Calculating Molecular Formulas
Hi!
One way I like to think of the two formulas is that the molecular formula is a MULTIPLE of the empirical formula. So, once you find your empirical formula (this is where you would have used division) you have to multiply to find your molecular formula.
One way I like to think of the two formulas is that the molecular formula is a MULTIPLE of the empirical formula. So, once you find your empirical formula (this is where you would have used division) you have to multiply to find your molecular formula.
Re: Last Step of Calculating Molecular Formulas
Also, Before you multiply, remember to divide the molar mass by the atomic mass from the empirical formula -- sometimes I forget to do this last step!
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Re: Last Step of Calculating Molecular Formulas
You would multiply. You would divide the sample's molar mass by the empirical formula's molar mass to find the ratio between them. Then you would multiply the empirical formula by the ratio you calculated which would give you the molecular formula.
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