Textbook questions: L.39

[Jenna 1G]

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.

Hi! I am not too sure how to start the process of figuring out the empirical formula of the oxide. Any help on how to complete this problem would be great!

[Ethan Hung 2A]

First, you'll need to consider the mass of the tin oxide created by excluding the crucible's mass. After that, you should be able to compare the mass of the reactants (given in the problem) and the mass of the product (as described in the previous sentence).

In doing so, you'll see how much mass was added in the form of oxygen, and you now have the masses of tin (assumed to be the same as before the reaction) and oxygen in the product. From here, find the mass composition percentages and solve the empirical formula. If you need any more help with this step, let me know. Hope that helped :)

[kylanjin]

The key part of the problem is where it gives you the weight of the crucible AND product. That gives you an equation you can use to find the amount of elements you need for the empirical formula.

ex. crucible + product = 28.35 grams
product = 28.3g - 26.45g (given) = 1.9g

Then, because the product is the tin plus the oxide (which is just the amount of oxygen reacted) that formed on it, you can then subtract the weight of the tin (1.50 g) from 1.9g (total weight of tin plus the oxide) to find the weight in grams of the oxide.

After that, convert the mass in grams of the tin and oxide to moles respectively, and I'm assuming that you know the drill from there! Hope this helped.

[Jenna 1G]

First, you'll need to consider the mass of the tin oxide created by excluding the crucible's mass. After that, you should be able to compare the mass of the reactants (given in the problem) and the mass of the product (as described in the previous sentence).

In doing so, you'll see how much mass was added in the form of oxygen, and you now have the masses of tin (assumed to be the same as before the reaction) and oxygen in the product. From here, find the mass composition percentages and solve the empirical formula. If you need any more help with this step, let me know. Hope that helped :)

Hi Ethan!
It would be great if you could help me out a little more. Since we are finding the empirical formula of the oxide (which is the product), would the only two elements we have to find the mass percentages be tin (Sn) and oxygen (O)?
Thank you!

[Ethan Hung 2A]

First, you'll need to consider the mass of the tin oxide created by excluding the crucible's mass. After that, you should be able to compare the mass of the reactants (given in the problem) and the mass of the product (as described in the previous sentence).

In doing so, you'll see how much mass was added in the form of oxygen, and you now have the masses of tin (assumed to be the same as before the reaction) and oxygen in the product. From here, find the mass composition percentages and solve the empirical formula. If you need any more help with this step, let me know. Hope that helped :)

Hi Ethan!
It would be great if you could help me out a little more. Since we are finding the empirical formula of the oxide (which is the product), would the only two elements we have to find the mass percentages be tin (Sn) and oxygen (O)?
Thank you!

Yes, that's correct -- since there are no other elements present in this specific reaction. After calculating the mass composition percentages, just divide by the molar mass for each element and you'll have a ratio that can be reduced down to a whole number.