Finding Molar Mass

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Kelsey Ash 1D
Posts: 50
Joined: Wed Sep 18, 2019 12:16 am

Finding Molar Mass

Postby Kelsey Ash 1D » Thu Oct 03, 2019 9:10 am

In an equations such as Part D of question E. 23 where the the molecular equation is shown as Na(subscript)2 CO(subscript) 3 dot 10H(subscript)2O do add or multiplayer;y to the 2 equations to find the total molecular mass because I have tried both ways and seem to be getting a different answer from the solutions manual.

Sahil Jog 1F
Posts: 126
Joined: Thu Jul 11, 2019 12:16 am

Re: Finding Molar Mass

Postby Sahil Jog 1F » Thu Oct 03, 2019 9:38 am

The dot simply means that the solution is a hydrate, and that you should figure out the total molar mass of the solution (roughly 286 g/mol). Then, using stoichiometry convert how many mols of water are produced with 2.00 g of that solution. Here is the chemical equation down below.

Na2CO3 * 10H2O ----> Na2CO3 + 10H2O

Basically what we did was we heated the hydrate and made it an anhydrous sample.

Fiona Latifi 1A
Posts: 102
Joined: Sat Sep 14, 2019 12:16 am

Re: Finding Molar Mass

Postby Fiona Latifi 1A » Thu Oct 03, 2019 9:42 am

In this question, you just add to find the molar mass. For Na2CO3 * 10H2O, you would compute 2(22.99) + 12.01 + 3(16) +10(18.02) = 286.19.

Joelle 3L
Posts: 50
Joined: Sat Jul 20, 2019 12:16 am

Re: Finding Molar Mass

Postby Joelle 3L » Thu Oct 03, 2019 3:06 pm

The chemical equation would be Na2CO3 * 10H2O -> Na2CO3 + 10H2O. You would find the molar mass of this equation by multiplying the factors by their respective molar masses. Therefore, 2(22.99) + 12.01 + 3(16) +10(18.02) = 286.19g.

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