## empirical and molecular formulas

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Joined: Thu Jul 11, 2019 12:17 am

### empirical and molecular formulas

can a compound's empirical formula be the same as its molecular formula? When can you tell?

Hannah Pham
Posts: 104
Joined: Fri Aug 09, 2019 12:17 am

### Re: empirical and molecular formulas

The empirical formula can be the same as the molecular formula. However, it will not always be if the molar mass of the molecular compound is larger than that of the empirical formula. The empirical formula is just the ratio of atoms in a compound.

Haley Pham 4I
Posts: 51
Joined: Fri Aug 09, 2019 12:16 am

### Re: empirical and molecular formulas

Yes, sometimes a compound's molecular formula can be the same as its empirical formula if the number of atoms in the empirical formula are the actual number of atoms in the molecular formula. The molecular formula can be the same as the empirical formula or a multiple of it. In a problem where it gives you the molar mass of the compound, you can divide that mass by the molar mass of the empirical formula you found, and if it is a multiple of 1, the molecular formula would be the same as the empirical formula in this case.

Rebekah Alfred 1J
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Joined: Thu Jul 11, 2019 12:15 am
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### Re: empirical and molecular formulas

To see if the empirical formula is the same as the molecular formula or if it is just the ratio, you have to find the molar mass of the empirical formula. If this molar mass is the same as the molar mass of molecular compound, you know that the empirical formula and molecular formula are the same. For example, the empirical formula and the molecular formula for water (H2O) are the same. If these numbers are different, then you divide the molar mass of the molecular compound by the mass of the empirical formula, which will give you a whole number or one that can be rounded to a whole number. You will multiply this whole number by the subscripts of the empirical formula to find the molecular formula.

Sean1F
Posts: 19
Joined: Sat Sep 07, 2019 12:16 am

### Re: empirical and molecular formulas

Remember to not be tricked! Sometimes many of my classmates forget to add the molar masses to compare it to the molar mass of the initial compound. It is always worth checking!!

105311039
Posts: 107
Joined: Fri Aug 02, 2019 12:16 am

### Re: empirical and molecular formulas

yes, you can tell when a molecular formula and the empirical formula are the same when you divide the molecular formula by the empirical formula and get 1. That means the ratios are similar and the formulas are the same.

Aarushi Solanki 4F
Posts: 107
Joined: Sat Jul 20, 2019 12:17 am

### Re: empirical and molecular formulas

Empirical formulas are ratios of the number of atoms of each type of element in a molecule, whereas molecular formulas include the actual number of atoms of each element in the molecule. If the molar mass of the empirical formula is equal to the molar mass given (actual molar mass), then the molecular formula is the same as the empirical formula.

SimranSangha4I
Posts: 99
Joined: Sat Sep 14, 2019 12:17 am

### Re: empirical and molecular formulas

Yes, it can! Since molecular formula tells you the amount of molecules in a compound and the empirical formula tells you the simplest ratio in a compound, if a compound's molecular formula cannot be reduced anymore, the empirical formula would be able to be the same as the molecular.