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1. Write a balanced chemical equation for each double replacement reaction that occurs.
Note: Compounds with Na+, K+, and/or NO3− are soluble.



2. Why was there no reaction in some of the wells? (See Introduction.)


3. How could you tell a Ca(NO3)2 solution from a Zn(NO3)2 solution?


4. How could you tell a Cu(NO3)2 solution from a Ni(NO3)2 solution?

Please help Thanks D 1 Write a balanced chemical equation for each double replacement reaction that occurs Note Compounds with Na K andor NO3 are soluble 2 Why class=

Respuesta :

jacob193

1

Species shown in bold are precipitates.

  • Ca(NO₃)₂ + 2 KOH → Ca(OH)₂ + 2 KNO₃
  • Ca(NO₃)₂ + Na₂C₂O₄ → CaC₂O₄ + 2 NaNO₃
  • Cu(NO₃)₂ + 2 KI → CuI₂ + 2 KI
  • Cu(NO₃)₂ + 2 KOH → Cu(OH)₂ + 2 KNO₃
  • Cu(NO₃)₂ + Na₂C₂O₄ → CuC₂O₄ + 2 NaNO₃
  • Ni(NO₃)₂ + 2 KOH → Ni(OH)₂ + 2 KNO₃
  • Ni(NO₃)₂ + Na₂C₂O₄ → NiC₂O₄ + 2 NaNO₃
  • Zn(NO₃)₂ + 2 KOH → Zn(OH)₂ + 2 KNO₃
  • Zn(NO₃)₂ + Na₂C₂O₄ → ZnC₂O₄ + 2 NaNO₃

2

A double replacement reaction takes place only if it reduces in the concentration of ions in the solution. For example, the reaction between Ca(NO₃)₂ and KOH produces Ca(OH)₂. Ca(OH)₂ barely dissolves. The reaction has removed Ca²⁺ and OH⁻ ions from the solution.

Some of the reactions lead to neither precipitates nor gases. They will not take place since they are not energetically favored.


3

Compare the first and last row:

Both Ca(NO₃)₂ and Zn(NO₃)₂ react with KOH. However, between the two precipitates formed, Ca(OH)₂ is more soluble than Zn(OH)₂.

As a result, add the same amount of KOH to two Ca(NO₃)₂ and Zn(NO₃)₂ of equal concentration. The solution that end up with more precipitate shall belong to Zn(NO₃)₂.


4

Compare the second and third row:

Cu(NO₃)₂ reacts with KI, but Ni(NO₃)₂ does not. Thus, add equal amount of KI to the two unknowns. The solution that forms precipitate shall belong to Cu(NO₃)₂.

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