[chokedirt]

im trying to do a practice exam quiz for a chemistry course im taking at uni. i work full time or i'd go and see my tutor about them i guess. if anyone could help out by giving me the steps/explanations or correcting what i've done that would be awesome. thanks.

What mass of carbon dioxide (in grams) is formed when 11.4 g of propanone (acetone) is burned in excess air?

(CH3)2CO + O2 -> CO2 + H2O balances to (CH3)2CO + 4O2 -> 3CO2 + 3H2O
so the ratio in mols of acetone to CO2 in general is 1:3.
3 mols of CO2 weighs 132.03g and 1 mols of acetone weighs 58.071g.
so from 11.4 g of acetone you get 25.87g of CO2... (11.40 / 58.071) * 132.03 = 25.87g ?

It seems too easy to get to that given how insanely hard i'm finding the rest of the questions. Anywayy. The others that I have absolutely no idea where to start with..

24.8 mL of 0.100 M sodium hydroxide solution is required to reach the endpoint when added to 20.0 mL of hydrochloric acid solution. What is the molarity of the hydrochloric acid solution?

andd

1 L of hydrogen chloride gas (25oC, 1 atmos. pressure) is dissolved in water and made up to 1 L of solution in a volumetric flask. What is the molar concentration of chloride ion in the resultant solution?

I can't really work out where to start with these two because the lecture notes are fairly vague. If someone could just explain them differently or give me the steps without solving them that would be really really awesome. hahh.

Thankss

[Borek]

so from 11.4 g of acetone you get 25.87g of CO2...

OK

24.8 mL of 0.100 M sodium hydroxide solution is required to reach the endpoint when added to 20.0 mL of hydrochloric acid solution. What is the molarity of the hydrochloric acid solution?

http://www.titrations.info/titration-calculation

1 L of hydrogen chloride gas (25oC, 1 atmos. pressure) is dissolved in water and made up to 1 L of solution in a volumetric flask. What is the molar concentration of chloride ion in the resultant solution?

If my guess about why you have problems is correct, after reading about titration you should do this question without problems. Just remember hydrochloric acid is 100% dissociated.

[Biopolmonkey]

For the last question, I would approach it from the angle that 1mol of ideal gas occupies 24L.