L.39  [ENDORSED]

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Faisal Alshamaa - 1L
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Joined: Fri Apr 06, 2018 11:01 am

L.39

Postby Faisal Alshamaa - 1L » Sun Apr 08, 2018 11:17 pm

Hello, I'm having a lot of trouble understanding this problem and its solution.

A 1.50-g sample of metallic tin was placed in a 26.45-g crucible and heated until all the tin had reacted with the oxygen in air to form an oxide. The crucible and product together were found to weigh 28.35 g. (a) What is the empirical formula of the oxide? (b) Write the name of the oxide.

I get that we have to eliminate the weight of the crucible and are left with 1.9 grams of product. Do we then just convert the 1.50 g of tin (Sn) to moles by dividing by molar mass, then doing the same for the product? The oxide is 1.9-1.5g? why?

Thank you!

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Re: L.39  [ENDORSED]

Postby Chem_Mod » Mon Apr 09, 2018 11:48 am

To approach this problem, the very first thing you should do is write out a balanced chemical equation. The problem states that tin reacts with oxygen to form an oxide, so we need to write a chemical equation accordingly. The problem essentially gives us the mass of product we have and the mass of tin we start with. Since tin reacts with oxygen to form the product, the mass of product-mass of tin= mass of oxygen reacted in the reaction. That is where 1.9g-1.5g came from. Once we know the masses of each element present in the product (tin and oxygen), you just use a mass percent to calculate the empirical formula.


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