Q&A for How to Find Molecular Formula

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How do I find molecular formulas?

Meredith Juncker, PhD
Scientific Researcher
Meredith Juncker is a scientific researcher based in Brookline, Massachusetts. Currently working as a Senior Patent Technology Specialist at Dana-Farber Cancer Institute, Meredith is able to leverage her expertise in biochemistry and molecular biology. She received a PhD in Biochemistry and Molecular Biology from Louisiana State University Health Sciences Center, focusing on proteins and neurodegenerative diseases. She went on to work as a Postdoctoral Associate at the Jacobs School of Medicine and Biomedical Sciences at the State University of New York at Buffalo.

Meredith Juncker, PhD

Scientific Researcher

Expert Answer

You can follow the steps above. Start by finding the empirical formula. You should then calculate the empirical formula weight. Then, divide the molecular formula weight by the empirical formula weight. This answer gives you the number you'll need to multiply the subscripts in the empirical formula to get the molecular formula. You can double check that you got the right answer by calculating the molecular molar mass of the molecular formula you calculated.

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A compound contains 3.2g of Cu, 0.6g of C and 2.4 O2. How do I find its empirical formula?

Community Answer

You would first need to convert each of the gram measurements to moles. Accomplish this by dividing each by its respective atomic mass on the periodic table. Then divide each measurement by the lowest mole amount. You can continue doing this until you get whole number subscripts.

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If the molar mass is 99 g/mol, what is the molecular formula?

Community Answer

We do not have enough information. It could be multiple elements in different ratios.

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If a compressed gas cylinders if having pressure 2100 psi at 21 Celsius, how do I calculate the volume of a cylinder?

Community Answer

You calculate the volume of the cylinder by calculating it the proper way, not the wrong way.

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