physics question

• yiha093

  7 Oct 07, 21:34

  a 1cm3 sample of tin lead alloy has a mass of 8.5g. the density of tin is 7.3g cm-3 and that of lead is 11.3g cm-3
  calculate the percentageby weight of tin in the alloy
  
  sec 2 standard , cmon la guys
• Eragon

  7 Oct 07, 21:39

  Originally posted by yiha093:

  a 1cm3 sample of tin lead alloy has a mass of 8.5g. the density of tin is 7.3g cm-3 and that of lead is 11.3g cm-3
  calculate the percentageby weight of tin in the alloy
  
  sec 2 standard , cmon la guys

  Wah lao eh!! insulted my IQ.
• yiha093

  7 Oct 07, 21:40

  Originally posted by Eragon:

  Wah lao eh!! insulted my IQ.

  wad i wana c is the solution
  
• Darkness_hacker99

  7 Oct 07, 21:43

  
  
  If we don't know the composition, any answer <99.999999999999% could be the answer!
• Scania N113CRB luver

  7 Oct 07, 21:44

  post deleted .
• lpx88

  7 Oct 07, 21:49

  Wads de vol of tin and lead respectively?
• yiha093

  7 Oct 07, 21:49

  Originally posted by Darkness_hacker99:

  
  
  If we don't know the composition, any answer <99.999999999999% could be the answer!

  hmm.... ok...
  any miore views?
• yiha093

  7 Oct 07, 21:50

  Originally posted by lpx88:

  Wads de vol of tin and lead respectively?

  not sure, i suppose we ahve to use the density formula?
  the D= sth sth de?
  but i 4got wad that is le... ><
• Eragon

  7 Oct 07, 21:57

  Originally posted by yiha093:

  not sure, i suppose we ahve to use the density formula?
  the D= sth sth de?
  but i 4got wad that is le... ><

  D =Mass/Vol ......
  
• tanjun

  7 Oct 07, 21:58

  Originally posted by yiha093:

  a 1cm3 sample of tin lead alloy has a mass of 8.5g. the density of tin is 7.3g cm-3 and that of lead is 11.3g cm-3
  calculate the percentageby weight of tin in the alloy
  
  sec 2 standard , cmon la guys

  let the percentage of the weight of tin in the alloy be a%.
  
  Percentage of the weight of lead in alloy = 100 - a %
  
  a/100 x 1 x 7.3 + (100 - a)(1/100)(1)(11.3) = 8.5
  
  7.3/100 (a) + (1-a/100)(11.3) = 8.5
  
  0.073 a + 11.3 - 0.113a = 8.5
  
  0.04 a = 2.8
  
  a = 70
  
  Percentage of the weight of tin = 70%
  Percentage of lead in alloy = 30%
  
  Then, check your ans back into the eqn.
  
  7.3 x 0.7 + 11.3 x 0.3 = 8.5 (proven)
  
  
• yiha093

  7 Oct 07, 22:02

  Originally posted by tanjun:

  let the percentage of the weight of tin in the alloy be a%.
  
  Percentage of the weight of lead in alloy = 100 - a %
  
  a/100 x 1 x 7.3 + (100 - a)(1/100)(1)(11.3) = 8.5
  
  7.3/100 (a) + (1-a/100)(11.3) = 8.5
  
  0.073 a + 11.3 - 0.113a = 8.5
  
  0.04 a = 2.8
  
  a = 70
  
  Percentage of the weight of tin = 70%
  Percentage of lead in alloy = 30%
  
  Then, check your ans back into the eqn.
  
  7.3 x 0.7 + 11.3 x 0.3 = 8.5 (proven)
  
  

  thx u all for help
• Deadly

  8 Oct 07, 19:00

  Originally posted by yiha093:

  thx u all for help

  My pleasure