Help with Chemistry work on mass?

Start with reaction equations.

Reply 2

OP

Original post by Borek

Start with reaction equations.

Reaction equations????

We have not been taught that?

Reply 3

Then I don't see how you can be asked about stoichiometry.

That is, it is possible to solve these problems without reaction equations, but it requires understanding that you typically learn through solving stoichiometry problems based on reaction equations.

Do you know what is aluminum oxide formula? Can you calculate what is mass percentage of aluminum in the aluminum oxide?

Reply 4

OP

Original post by Borek

Then I don't see how you can be asked about stoichiometry.

That is, it is possible to solve these problems without reaction equations, but it requires understanding that you typically learn through solving stoichiometry problems based on reaction equations.

Do you know what is aluminum oxide formula? Can you calculate what is mass percentage of aluminum in the aluminum oxide?

I have a slight idea how to calculate it, but I do not really understand. Sorry to be a pain!

Reply 5

OP

Basically we were told to find a method and work out one of these in class, and I found a method, but it is confusing. Plus, that is in class, which is annoying, as I do not remember the whole method. We have been told to research, as our teacher does not want to 'dictate' in front of the whole class, and needs us to learn it ourselves.

Reply 6

Start with the formula. Calculate molar mass of the oxide. Calculate molar mass of just the aluminum present. What is the fraction of the metal in the oxide? You want 500 tonnes of the metal - set up a ratio and solve for the oxide mass.

Reply 7

OP

I am rubbish with Maths too!

The formula for Aluminum Oxide is AL203
The Molar Mass is 101.96 g

I do not really know how to calculate a fraction of the metal in the oxide, and I can not do ratios! :frown:

I'm only in Yr10, and we are not usually asked anything that we have no idea about!

Reply 8

Molar mass is OK.

Now, there are two atoms of Al in the molecule. What is their mass?

Reply 9

OP

Original post by Borek

Molar mass is OK.

Now, there are two atoms of Al in the molecule. What is their mass?

The mass for one is 27? So wouldn't two be 54?

Reply 10

Yes.

Now, regardless of the mass of the oxide, ratio of metal mass to the oxide mass is always the same:

\frac {metal\ mass}{oxide\ mass} = \frac {55\ g} {102\ g} = \frac {500\ tonnes}{x\ tonnes}

Solve for x.

Reply 11

OP

So the ratio of the oxide would be 500 tonnes too?

Reply 12