## L.39

Kevin Pilcher 3E
Posts: 42
Joined: Wed Sep 30, 2020 9:40 pm

### L.39

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.
To get the mass of oxygen in the equation, why do we subtrtacti 28.35 g by 26.45 g? I got the answer but I'd love some further explanation so that I can understand the concept behind it.

Juliet Cushing_2H
Posts: 44
Joined: Wed Sep 30, 2020 9:39 pm

### Re: L.39

The crucible is the vessel that allows for this reaction, however, the mass of the product is all we want to look at when answering this Empirical Formula question. Subtracting 26.45g (mass of crucible) from 28.35g (mass of crucible + mass of product) means that we are left with just the mass of the product = 1.9g.

If the product (comprised of Tin and Oxygen) weighs 1.9g and we already know that the mass of Tin we started with was 1.5g, we can deduce that the mass of oxygen needed for this experiment is 1.9g-1.5g. From there use the classic Empirical Formula steps to solve the question :) hope this helps!

Ashley Ko 2K
Posts: 47
Joined: Wed Sep 30, 2020 9:54 pm

### Re: L.39

The reason behind subtracting 26.45 g from 28.35 g is to only get the mass of the product. For example, in order to obtain the mass of the product, tin oxide, one needs to subtract the mass of the crucible from the total mass. Then, in order to obtain the mass of the oxygen, one needs to subtract 1.50 g (the mass of the metallic tin) from the mass of the product. The main concept in finding the mass of the oxygen is the law of the conservation of mass. Hope this helps!

Kevin Pilcher 3E
Posts: 42
Joined: Wed Sep 30, 2020 9:40 pm

### Re: L.39

Juliet Cushing_2H wrote:The crucible is the vessel that allows for this reaction, however, the mass of the product is all we want to look at when answering this Empirical Formula question. Subtracting 26.45g (mass of crucible) from 28.35g (mass of crucible + mass of product) means that we are left with just the mass of the product = 1.9g.

If the product (comprised of Tin and Oxygen) weighs 1.9g and we already know that the mass of Tin we started with was 1.5g, we can deduce that the mass of oxygen needed for this experiment is 1.9g-1.5g. From there use the classic Empirical Formula steps to solve the question :) hope this helps!

Thank you! That explanation helped a lot!