study on exam q's

[jaja]

here are some q's from "study on" Chemistry 2 exam..

Q7) MC
in a titration, 0.055 g of a monoprotic acid was neutralised by 9.17 mL of 0.1 mol L-1 KOH. The monoprotic acid must be.
a. HCL b. HNO3 c. CH3COOH d. CH3CH2COOH
the answer is c .. but why.. wouldn't it be hcl or Hno3, as they only donate one hydrogen??/

Q11) A chemist analyses a 5g ore sample of chalcopyrite, CuFeS2. A gravimetric anaysis is carried out so that all the sulfur in CuFeS2 is precipitated as BaSO4. The amount of BaSO4 is determined to be 0.1 mol. What is the % mass of sulfur in the ore?...the answer is 64%

Q16) which of the following chemicals would be needed to synthesise 2,3 dichlorobutane?
the answer is butene and Cl2..but how??/

[Edmund]

Question 7
 ,m

Question 11

Using mole ratios, there is 0.1mol of Sulfur in BaSO4
Therefore, mass of sulfur in the precipitate = 0.1 x 32.1 = 3.21g

Mass of original sample, CuFeS2 = 5g

So, (3.21/5.0) x 100% = 64.2%

Question 16

Butene is an alkene and has a double bond. When reacted with Cl2, butene can lose the double bond, and Cl2 can form C-Cl bonds with it to form 2,3 dichlorobutane.

[Mao]

Q7, if you look at the choices, they are all monoprotic acids (Hydrochloric, nitric, ethanoic and propanoic). The key here is to find the number of moles of acid that reacted in the titration, then the molar mass.

[jaja]

However, when you draw that, the chlorine is on the 1 and 2 carbon...so you can't realli say it's a 2,3 dichlorobutane

also which one is more soluble in water hydoxyl or carboxylic functional group???

[Mao]

However, when you draw that, the chlorine is on the 1 and 2 carbon...so you can't realli say it's a 2,3 dichlorobutane

but-2-ene

also which one is more soluble in water hydoxyl or carboxylic functional group???

which one is more polar?