Midterm question 1

Moderators: Chem_Mod, Chem_Admin

Posts: 111
Joined: Wed Sep 18, 2019 12:19 am

Midterm question 1

Postby JustinHorriat_4f » Sun Nov 10, 2019 10:38 pm

Does anyone know how they did question 1, the empirical formula one, on the midterm? I did not know how I was able to take the grams of some of the products and use mole to mole ratio to go to the empirical formula for the reactant.

Hussain Chharawalla 1G
Posts: 100
Joined: Sat Jul 20, 2019 12:15 am

Re: Midterm question 1

Postby Hussain Chharawalla 1G » Sun Nov 10, 2019 10:50 pm

The empirical formula of Riboflavin is C17H20N4O6.

I solved it by identifying the conservation of matter in the reaction, and counted the number of atoms on each end of the reaction to form the empirical formula with the remaining atoms.

Lauren Lewis3L
Posts: 57
Joined: Wed Feb 20, 2019 12:16 am

Re: Midterm question 1

Postby Lauren Lewis3L » Sun Nov 10, 2019 10:54 pm

As far as I got on that problem was similar to how you solve for the one that was on Dino Nuggets. I'm pretty sure that the one on the Dino Nuggets was question one as well. I just tried to get as much as I could on the paper. I did some conversions and also did some mole to mole ratio for each of the elements. I think you had to add them all up and eventually subtract from I believe oxygen since it was in both reactants.

Posts: 105
Joined: Sat Jul 20, 2019 12:16 am

Re: Midterm question 1

Postby Julie_Reyes1B » Sun Nov 10, 2019 10:55 pm

For midterm question 1, you had to convert CO2 to C using the mol to mol ratio 1 mol CO2=1 mol C. Do that for all 3 to find grams of C, N, and H. Then subtract all of the grams from grams of compound to get grams of oxygen. Then you can proceed with the empirical formula analysis as usual.

Adelpha Chan 1B
Posts: 58
Joined: Thu Jul 25, 2019 12:15 am

Re: Midterm question 1

Postby Adelpha Chan 1B » Tue Nov 12, 2019 12:15 pm

the first step to solving question 1 is to find the mass of carbon, hydrogen, nitrogen and oxygen in the final compound. The amount of carbon, hydrogen, and nitrogen are found by using dimensional analysis of the given weight of the resulting compounds in relation to mole ratios and molar mass. Add those up and subtract from the known weight of the unknown product in order to determine the mass of oxygen (as it exists in excess). Once the weight of each element is determined, proceed the same way you would with the molecular and empirical formula questions shown in the textbook, during lecture, and in the Dino Nuggets packet.

Rita Chen 1B
Posts: 112
Joined: Sat Jul 20, 2019 12:15 am

Re: Midterm question 1

Postby Rita Chen 1B » Tue Nov 12, 2019 12:34 pm

Do you guys think if I wrote it in the wrong order, it would be ok? Or would it be partial credit.

Jade Hinds 2B
Posts: 75
Joined: Tue Sep 10, 2019 12:16 am

Re: Midterm question 1

Postby Jade Hinds 2B » Sat Dec 07, 2019 12:15 pm

What's the step to step process on how to solve this problem? because I am lost

I get that that you have to first convert from grams to moles... but what do you do next?

Return to “Empirical & Molecular Formulas”

Who is online

Users browsing this forum: No registered users and 1 guest