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SIMpLiFy

81 posts since Jun '06
- 23 Jan `08, 8:40PM
  
  In an experiment,excess zinc powder reacts with 50cm cube of 0.1dm cube/mol sulphuric acid in an experiment.The products formed in the reaction are zinc sulphate and hydrogen gas.
  
  (a)Write a balanced equation for the reaction.
  (b)Determine the volume of hydrogen gas produced in the reaction.
  
  Thanks.
SBS3625D

4,076 posts since Sep '05
- 23 Jan `08, 9:01PM
  
  WTF.
  
  You might as well give me a table, a calculator and your exam paper?
  
  Do it yourself please....there's only so much we can help you.
wishboy

1,269 posts since Aug '05
- 23 Jan `08, 9:42PM
  
  Originally posted by SIMpLiFy:
  
  In an experiment,excess zinc powder reacts with 50cm cube of 0.1dm cube/mol sulphuric acid in an experiment.The products formed in the reaction are zinc sulphate and hydrogen gas.
  
  (a)Write a balanced equation for the reaction.
  (b)Determine the volume of hydrogen gas produced in the reaction.
  
  Thanks.
  
  a)
  Zn (s) + H2SO4 (aq) ----> ZnSO4 (aq) + H2 (g)
  
  b)
  No. of mol H2SO4
  = 0.05/0.1
  = 0.5 mol
  
  Vol. of H2
  = 0.5*24
  = 12 dm³
  
  i not sure whether my answers correct anot
  anyway try to understand how to do
  anything dunno ask ur teacher/classmate/anyone who noes how to do
  
  Edited by wishboy 23 Jan `08, 9:43PM
SIMpLiFy

81 posts since Jun '06
- 24 Jan `08, 9:49PM
  
  ok..sry , i just noticed my teacher havn’t taught this topic yet , nowonder it looks so unfamiliar..well thx anyway =D.
gnab

134 posts since Jan '08
- 24 Jan `08, 10:05PM
  
  6Zn (s) + 2HSO4 (aq) -> 2Zn3SO4 (s) + H2 ( g)
  
  no of mol of HSO4 used = (50/1000)/.1 = 0.5mol
  no of mol of H2 produced = no of mol of HSO4 = 0.5mol
  
  hope my answer is useful..
wishboy

1,269 posts since Aug '05
- 24 Jan `08, 10:26PM
  
  Originally posted by gnab:
  
  6Zn (s) + 2HSO4 (aq) -> 2Zn3SO4 (s) + H2 ( g)
  
  no of mol of HSO4 used = (50/1000)/.1 = 0.5mol
  no of mol of H2 produced = no of mol of HSO4 = 0.5mol
  
  hope my answer is useful..
  
  er
  how come in ur equation sulphuric acid is HSO4? not H2SO4 meh?
BaoBei92

153 posts since May '05
- 05 Mar `08, 6:34PM
  
  Originally posted by wishboy:
  
  er
  how come in ur equation sulphuric acid is HSO4? not H2SO4 meh?
  
  6Zn (s) + 2HSO4 (aq) -> 2Zn3SO4 (s) + H2 ( g)
  
  he used 2HSO4. probably typo.
Moderator

Darkness_hacker99

31,746 posts since Jun '05
- 06 Mar `08, 6:19AM
  
  This topic is about Limiting Reactant and Chemical Calculation. Limiting reacting as in 'not in excess'.
  
  First must find out which is the limiting reactant, before you can do the calculation. Since zinc power is in excess, then sulpuhruic will be the limiting reactant.
  
  Next is to find the no. of mol of sulphuric acid. With that, you can then calculate volume of hydrogen gas produced.
  
  Edited by Darkness_hacker99 06 Mar `08, 4:10PM
Moderator

Darkness_hacker99

31,746 posts since Jun '05
- 06 Mar `08, 6:22AM
  
  It's H₂SO₄ at O Level.
  
  Edited by Darkness_hacker99 06 Mar `08, 6:23AM
Moderator

Darkness_hacker99

31,746 posts since Jun '05
- 06 Mar `08, 4:07PM
  
  Originally posted by wishboy:
  
  a)
  Zn (s) + H2SO4 (aq) ----> ZnSO4 (aq) + H2 (g)
  
  b)
  No. of mol H2SO4
  = 0.05/0.1
  = 0.5 mol
  
  Vol. of H2
  = 0.5*24
  = 12 dm³
  
  i not sure whether my answers correct anot
  anyway try to understand how to do
  anything dunno ask ur teacher/classmate/anyone who noes how to do
  
  Your answer correct.
weewee

498 posts since Aug '03
- 06 Mar `08, 4:15PM
  
  Originally posted by wishboy:
  
  a)
  Zn (s) + H2SO4 (aq) ----> ZnSO4 (aq) + H2 (g)
  
  b)
  No. of mol H2SO4
  = 0.05/0.1
  = 0.5 mol
  
  Vol. of H2
  = 0.5*24
  = 12 dm³
  
  i not sure whether my answers correct anot
  anyway try to understand how to do
  anything dunno ask ur teacher/classmate/anyone who noes how to do
  
  Why is it *24?
  
  Holy i have forgotten my chemistry.
weewee

498 posts since Aug '03
- 06 Mar `08, 4:20PM
  
  now i remember the formula 1 mole = 24dm3 but forgot why.
Moderator

Darkness_hacker99

31,746 posts since Jun '05
- 06 Mar `08, 4:21PM
  
  Molar Gas Volume = 24dm³
  
  It's the amount of volume occupied by 1 mole of gas molecule @ r.t.p
  
  Edited by Darkness_hacker99 06 Mar `08, 4:22PM
Moderator

eagle

17,968 posts since Aug '01
- 06 Mar `08, 4:22PM
  
  Originally posted by weewee:
  
  now i remember the formula 1 mole = 24dm3 but forgot why.
  
  0.5 mole of H2SO4 still consists of 0.5 mole of H2.
  
  So volume of H2 produced from 0.5 mol of H2SO4 is still 0.5 mol of H2 (because it is by number of molecules).
  
  Since 1 mole = 24dm3, 0.5 mol = 12 dm3 of H2