0.8 Reactions in aqueous solutions  (Page 7/10)

 Page 7 / 10

Method:

1. Prepare 2 test tubes with approximately 5 ml of dilute Cu(II) chloride solution in each
2. Prepare 1 test tube with 5 ml sodium carbonate solution
3. Prepare 1 test tube with 5 ml sodium sulphate solution
4. Carefully pour the sodium carbonate solution into one of the test tubes containing copper(II) chloride and observe what happens
5. Carefully pour the sodium sulphate solution into the second test tube containing copper(II) chloride and observe what happens

Results:

1. A light blue precipitate forms when sodium carbonate reacts with copper(II) chloride
2. No precipitate forms when sodium sulphate reacts with copper(II) chloride

It is important to understand what happened in the previous demonstration. We will look at what happens in each reaction, step by step.

1. Reaction 1: Sodium carbonate reacts with copper(II) chloride.
When these compounds react, a number of ions are present in solution: ${\mathrm{Cu}}^{2+}$ , ${\mathrm{Cl}}^{-}$ , ${\mathrm{Na}}^{+}$ and ${\mathrm{CO}}_{3}^{2-}$ . Because there are lots of ions in solution, they will collide with each other and may recombine in different ways. The product that forms may be insoluble, in which case a precipitate will form, or the product will be soluble, in which case the ions will go back into solution. Let's see how the ions in this example could have combined with each other:
${\mathrm{Cu}}^{2+}+{\mathrm{CO}}_{3}^{2-}\to {\mathrm{CuCO}}_{3}$
${\mathrm{Cu}}^{2+}+2{\mathrm{Cl}}^{-}\to {\mathrm{CuCl}}_{2}$
${\mathrm{Na}}^{+}+{\mathrm{Cl}}^{-}\to \mathrm{NaCl}$
$2{\mathrm{Na}}^{+}+{\mathrm{CO}}_{3}^{2-}\to {\mathrm{Na}}_{2}{\mathrm{CO}}_{3}$
You can automatically exclude the reactions where sodium carbonate and copper(II) chloride are the products because these were the initial reactants. You also know that sodium chloride ( $\mathrm{NaCl}$ ) is soluble in water, so the remaining product (copper carbonate) must be the one that is insoluble. It is also possible to look up which salts are soluble and which are insoluble. If you do this, you will find that most carbonates are insoluble, therefore the precipitate that forms in this reaction must be ${\mathrm{CuCO}}_{3}$ . The reaction that has taken place between the ions in solution is as follows:
$2{\mathrm{Na}}^{+}+{\mathrm{CO}}_{3}^{2-}+{\mathrm{Cu}}^{2+}+2{\mathrm{Cl}}^{-}\to {\mathrm{CuCO}}_{3}+2{\mathrm{Na}}^{+}+2{\mathrm{Cl}}^{-}$
2. Reaction 2: Sodium sulphate reacts with copper(II) chloride.
The ions that are present in solution are ${\mathrm{Cu}}^{2+}$ , ${\mathrm{Cl}}^{-}$ , ${\mathrm{Na}}^{+}$ and ${\mathrm{SO}}_{4}^{2-}$ . The ions collide with each other and may recombine in different ways. The possible combinations of the ions are as follows:
${\mathrm{Cu}}^{2+}+{\mathrm{SO}}_{4}^{2-}\to {\mathrm{CuSO}}_{4}$
${\mathrm{Cu}}^{2+}+2{\mathrm{Cl}}^{-}\to {\mathrm{CuCl}}_{2}$
${\mathrm{Na}}^{+}+{\mathrm{Cl}}^{-}\to \mathrm{NaCl}$
${\mathrm{Na}}^{+}+{\mathrm{SO}}_{4}^{2-}\to {\mathrm{Na}}_{2}{\mathrm{SO}}_{4}$
If we look up which of these salts are soluble and which are insoluble, we see that most chlorides and most sulphates are soluble. This is why no precipitate forms in this second reaction. Even when the ions recombine, they immediately separate and go back into solution. The reaction that has taken place between the ions in solution is as follows:
$2{\mathrm{Na}}^{+}+{\mathrm{SO}}_{4}^{2-}+{\mathrm{Cu}}^{2+}+2{\mathrm{Cl}}^{-}\to 2{\mathrm{Na}}^{+}+{\mathrm{SO}}_{4}^{2-}+{\mathrm{Cu}}^{2+}+2{\mathrm{Cl}}^{-}$

[link] shows some of the general rules about the solubility of different salts based on a number of investigations:

 Salt Solubility Nitrates All are soluble Potassium, sodium and ammonium salts All are soluble Chlorides, bromides and iodides All are soluble except silver, lead(II) and mercury(II) salts (e.g. silver chloride) Sulphates All are soluble except lead(II) sulphate, barium sulphate and calcium sulphate Carbonates All are insoluble except those of potassium, sodium and ammonium Compounds with fluorine Almost all are soluble except those of magnesium, calcium, strontium (II), barium (II) and lead (II) Perchlorates and acetates All are soluble Chlorates All are soluble except potassium chlorate Metal hydroxides and oxides Most are insoluble

I only see partial conversation and what's the question here!
what about nanotechnology for water purification
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
what is the stm
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
what is Nano technology ?
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
why we need to study biomolecules, molecular biology in nanotechnology?
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
why?
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
research.net
kanaga
sciencedirect big data base
Ernesto
Introduction about quantum dots in nanotechnology
what does nano mean?
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
absolutely yes
Daniel
how to know photocatalytic properties of tio2 nanoparticles...what to do now
it is a goid question and i want to know the answer as well
Maciej
Abigail
for teaching engĺish at school how nano technology help us
Anassong
How can I make nanorobot?
Lily
how did you get the value of 2000N.What calculations are needed to arrive at it
Privacy Information Security Software Version 1.1a
Good
What makes metals better to use as wires than non-metals? (please link to bonding type)??? HELP