March 29, 2024, 09:16:05 AM
Forum Rules: Read This Before Posting


Topic: 2005 A Level questions for me  (Read 4006 times)

0 Members and 1 Guest are viewing this topic.

HongKongALevelboy

  • Guest
2005 A Level questions for me
« on: April 20, 2005, 05:03:21 AM »
hi , i just took my Hong Kong A Level exam on 4/19
i have a question on it

Question :
X is a trivalent metal . when treated with HCl , H gives Hydrogen , while its oxide undergoes neutralization.
16.5g of a mixture of X(s) and X2O3 (s) is allowed to react with 6M HCl(aq) . 0.0954dm3 of the acid is needed for both the metal and its oxide to undergo complete reaction.Based on this information , Deduce respectively the greatest value and the smallest possible value of the relative atomic mass of X

thx for any answer

Offline Borek

  • Mr. pH
  • Administrator
  • Deity Member
  • *
  • Posts: 27635
  • Mole Snacks: +1799/-410
  • Gender: Male
  • I am known to be occasionally wrong.
    • Chembuddy
Re:2005 A Level questions for me
« Reply #1 on: April 20, 2005, 05:47:47 AM »
Your sample contains x g of metal and (16.5 - x)g of oxide. Put y as the molar mass and create the equation describing amount of HCl needed for the complete reaction of the sample. It will have the from V = f(x,y) - everything else is a math.
ChemBuddy chemical calculators - stoichiometry, pH, concentration, buffer preparation, titrations.info

Offline AWK

  • Retired Staff
  • Sr. Member
  • *
  • Posts: 7979
  • Mole Snacks: +555/-93
  • Gender: Male
Re:2005 A Level questions for me
« Reply #2 on: April 20, 2005, 05:57:23 AM »
Hint
Treat this mixture as pure metal for the greatest number, and as pure oxide for the smallest one (85.6 - 61.6)
« Last Edit: April 20, 2005, 05:57:57 AM by AWK »
AWK

Sponsored Links