[leslieseesincolor]

Part of our exam was take home, because our teacher knew we wouldn't have time to complete the entire thing. Could you help me with this problem? Thank you very much

1.  An organic substance is synthesized and purified. It is known to contain carbon, hydrogen, and oxygen. A .500 gram sample is burned in excess oxygen with a copper catalyst to ensure complete combustion. The gases produced pass through a drying tube containing calcium chloride. A second tube contains sodium hydroxide that absorbs the carbon dioxide. The drying tube increases in mass by .385 g, and the second tube increases by 1.256 g
a) What is the percentage of carbon in the sample?
b) What is the percentage of hydrogen in the sample?
c) What is the percent of oxygen in the sample?
d) What is the empirical formula of the compound?
e) The condition of electricity is not increased when the compound is dissolved in water. This compound can be classified as a(n) ____________. Explain your answer


Also could you confirm my answers on another problem:
1a. A strip of magnesium is added to a solution of nitrate
    -Mg + 2AgNO3 = 2Ag + Mh(NO3)2
1b. Which substance is oxidized in the reaction?
    -Magnesium
2a. The complete combustion of acetic acid?
    -CH3COOH + 2O2 = 2CO2 +2H2O
2b. What product forms if oxygen is in limited supply
    -CO2 AND H2O  (?)
3a. Equal moles of potassium hydroxide and sulfuric acid are mixed
    -2KOH + H2SO4 = 2H2O + K2SO4
3b. If you were titrating sulfurous acid with potassium hydroxide, what would this solution's composition represent?
    -

Once again thank you!

[Borek]

Please read forum rules.

You have to show your attempts at solving the question to receive help. This is a forum policy.

2b is wrong, 3a calls for equal moles - that's not what you balanced, you have two moles of KOH per mole of H₂SO₄.

[leslieseesincolor]

Oh I'm sorry this is my first post and I didn't really read the rules.

Would the answer to 2b be that liquid H2O and gas CO2? Or would nothing form at all because both of these things need oxygen?

Is there a way to balance 3a with equal moles? I haven't been able to think of one.


And here is my attempt at number 1:
a) What is the percentage of carbon in the sample?
        -20.88% C
b) What is the percentage of hydrogen in the sample?
        -2.62% H
c) What is the percent of oxygen in the sample?
        -76.53%
d) What is the empirical formula of the compound?
        -C2H3O6

[Borek]

Burning carbon when there is not enough oxygen is dangerous.

Have you ever seen sodium bicarbonate?

Neither of your percentages is correct.