Help me in this Question. pls.

• Darkness_hacker99

  7 Feb 06, 17:12

  Zinc reacts with hydochloric acid according to the equation.
  
  Zn + 2HCl --> ZnCl2 + H2
  
  If 0.05 mole of zinc react with 0.075 mole of hydrochloric acid,
  
  (a) identify the limiting reactant
  
  (b) calculate the amount (in mole) of the excess reactant which remain unreacted.
  
  My ans for (a) is HCl. But my teacher says is Zn. Pls enlighten me.
  
  My class and I strongly believe the answer to (a) is HCl.
• chanff8

  7 Feb 06, 17:32

  (a) is HCl wad... Cos 2 parts of HCl reacts with one part of Zn. 0.05 moles of Zn can react with 0.1 mole of HCl, but HCl not enough, only 0.075 moles.
  
  (b)
  Since HCl is the limiting reactant, the number of moles of Zn it can react with is:
  0.075/2=0.0375 moles
  
  Remaining number of moles of Zn=0.05-0.0375=0.0125 moles
• Darkness_hacker99

  7 Feb 06, 17:44

  Originally posted by chanff8:

  (a) is HCl wad... Cos 2 parts of HCl reacts with one part of Zn. 0.05 moles of Zn can react with 0.1 mole of HCl, but HCl not enough, only 0.075 moles.
  
  (b)
  Since HCl is the limiting reactant, the number of moles of Zn it can react with is:
  0.075/2=0.0375 moles
  
  Remaining number of moles of Zn=0.05-0.0375=0.0125 moles

  Thank You wor. Hehe, tomorrow I can correct my teacher's mistake. Wahahaoa. Xie xie.
• chanff8

  7 Feb 06, 17:45

  Originally posted by Darkness_hacker99:

  Thank You wor. Hehe, tomorrow I can correct my teacher's mistake. Wahahaoa. Xie xie.

  yr welcome
• ^tamago^

  7 Feb 06, 19:48

  Originally posted by Darkness_hacker99:

  Thank You wor. Hehe, tomorrow I can correct my teacher's mistake. Wahahaoa. Xie xie.

  wait. what's the mistake that u said about?
• chanff8

  7 Feb 06, 19:59

  Originally posted by ^tamago^:

  wait. what's the mistake that u said about?

  His teacher thought that Zn is the limiting reactant
• ndmmxiaomayi

  7 Feb 06, 21:06

  But that is based on moles only. If grams or kilograms come into play, this calculation could well be correct.
• FadeToBlack

  7 Feb 06, 21:15

  kaoz so long nv practice chemistry already!!
  
  after no levels dont dare to see them..
  
  but last time my moles and calculations in chemistry do very fast and number 1 always correct..
• Allen.Iverson

  7 Feb 06, 21:16

  damn im taking chem and it sucks, especially acids, bases salts. i cant even grasp the topic at all!!
• sugarkitty

  7 Feb 06, 21:19

  hydrochloric acid is the limiting reagent, find by using mole ratio.
  
  so obvious, ask your teacher go home lah.
• Darkness_hacker99

  7 Feb 06, 21:27

  Originally posted by sugarkitty:

  hydrochloric acid is the limiting reagent, find by using mole ratio.
  
  so obvious, ask your teacher go home lah.

  Me use mole ratio too