A. good conductors - copper, aluminium
b. fair conductors - carbon,human body
c. insulator - paper, wood
<u>Answer:</u> The mass of sodium chloride solution present is 0.256 grams.
<u>Explanation:</u>
We are given:
39.0 % of sodium in sodium chloride solution
This means that 39.0 grams of sodium is present in 100 grams of sodium chloride solution
Mass of sodium given = 100 mg = 0.1 g (Conversion factor: 1 g = 1000 mg)
Applying unitary method:
If 39 grams of sodium metal is present in 100 grams of sodium chloride solution
So, if 0.1 grams of sodium metal will be present in = 
of sodium chloride solution.
Hence, the mass of sodium chloride solution present is 0.256 grams.
<h3><u>Answer</u>;</h3>
A. When a reaction is at chemical equilibrium, a change in the system will cause the system to shift in the direction that will balance the change and help the reaction regain chemical equilibrium.
<h3><u>Explanation</u>;</h3>
- Le Chatelier's principle states that when a change or a "stress" is placed on a system that is at equilibrium, the system will shift in such a way to relieve that change or stress.
- The stresses include; changing the concentration of reactants or products, altering the temperature in the system and changing the pressure of the system.
- Therefore; <u><em>when a chemical reaction is at equilibrium and experiences a change in pressure, temperature, or concentration of products or reactants, the equilibrium shifts in the opposite direction to offset the change. </em></u>
Energy cannot be destroyed or created, but energy could be transformed or transferred. For example a skiier skiing from the mouth can have potential energy transferred into kinetic energy.
