WANT 10 EASY POINTs? ANSWER THIS EASY CHEMISTRY QUESTION!!!?

Question

5. How many moles of molecules of aspirin C9H8O4, are there in a 100.0 mg tablet of aspirin?

6. Calculate the percentage composition of (NH4)2CO3

Answer 1

I'll get you started on your homework...

5) You have the formula for aspirin, so what is its atomic mass?

C9H8O4:
9 C * 12.011 = 108.10 (60% of mass)
8 H * 1.00794 = 8.06 (4.48% of mass)
4 O * 15.9994 = 64 (35.52% of mass)
Total:180.16 g/mole

So in one mole of aspirin, there are 180.16 g. If you have only 100 mg, how many moles is that?

First, convert the units to mg:

1 mole/180.16 g = 1 mmole/180.16 mg

Now set up a ratio:

1 mmole/180.16 mg = x mmole/100 mg

Solve for x:

100mg * (1 mmole/180.16 mg) = 0.56 mmoles

Now you know the number of moles. How many molecules is this? Use Avogadro's number (6.023 x 10^23 molecules/mole):

6.023 x 10^23 * 0.56 = 3.37 x 10^23 molecules

6) Percent composition of ammonium carbonate ... I'm not quite sure what you mean by this, but I'm assuming what percent is each atom in the molecular weight. If so, do this the same way I calculated aspirin above, that is, get the atomic mass and calculate:

(NH4)2CO3:
2 N * 14.0067 = 28.01 (29.15% of mass)
8 H * 1.00794 = 8.06 (8.39% of mass)
1 C * 12.011 = 12.01 (12.50% of mass)
3 O * 15.9994 = 48 (49.95% of mass)

Hope this helps!

Hey! It's been a full day - where are my points?! ;-)

Answer 2

5. Theres the formulas for your homework questions

5. 100 mg = 0.1 g

moles = 0.1 g / molecular mass of (C9H8O4)

6. %% = molecular mass of (NH4)/molecular mass of NH4CO3 x 100%

You could had worked these out in the time it has taken you to write this question.

Answer 3

That's two questions and they look like homework.

Answer 4

that looks to be quite a bit like homework, and sorry punkin, I'm not gonna do it for you! :-)