Answer:

Explanation:
The valency of aluminium is +3 while the valency of chlorine is -1
we will first write the half reactions
Half oxidation reaction

Now will write the complete equation-

The balanced equation would be

Answer:
Groundwater pollution
Explanation:
Pesticides, when sprayed on crop plants, are able to flow below the surface of the ground, reaching water-bearing aquifers, thereby contaminating groundwater, making it unsuitable for both human and agricultural uses.
Answer:
Number of moles is defined as the ratio of given mass in g to the molar mass.The mathematical expression is given as:
Number of moles =Number of moles of compound = 12.7 moles (given)As, 1 mole of any compound is equal to particles.
where, is Avogadro number. Formula for calculating particles is given by:
where, N = number of particles, n = number of moles and is Avogadro number.
Put the values,= or Hence, number of particles of the compound is equal to
Explanation:
Answer:
Density, melting point. and magnetic properties
Explanation:
I can think of three ways.
1. Density
The density of Cu₂S is 5.6 g/cm³; that of CuS is 4.76 g/cm³.
It should be possible to distinguish these even with high school equipment.
2. Melting point
Cu₂S melts at 1130 °C (yellowish-red); CuS decomposes at 500 °C (faint red).
A Bunsen burner can easily reach these temperatures.
3. Magnetic properties
You can use a Gouy balance to measure the magnetic susceptibilities.
In Cu₂S the Cu⁺ ion has a d¹⁰ electron configuration, so all the electrons are paired and the solid is diamagnetic.
In CuS the Cu²⁺ ion has a d⁹ electron configuration, so all there is an unpaired electron and the solid is paramagnetic.
A sample of Cu₂S will be repelled by the magnetic field and show a decrease in weight.
A sample of CuS will be attracted by the magnetic field and show an increase in weight.
In the picture below, you can see the sample partially suspended between the poles of an electromagnet.