“Tribasic” means one mole of the acid will dissociate in water to produce 3 moles of hydrogen ions.
“weak acid” means that the acid molecules dissociate partially when dissolved in water to produce a low concentration of hydrogen ions.
Category: Pure Chemistry
Describe a simple test for the presence of a reducing agent using aqueous potassium manganate (VII) solution.
Add a few drops of acidified potassium manganate(VII) solution to a solution containing an unknown agent.
If a reducing agent is present in the solution, the KMnO4 solution will turn from purple to colorless.
In the presence of a reducing agent, a redox reaction occurs, turning the Mn7+ ion in KMnO4 (which is purple) to Mn2+ ion (which is colorless or slightly pinkish).
Describe a simple test for the presence of an oxidizing agent using aqueous potassium iodide.
Add a few drops of aqueous potassium iodide to a solution containing an unknown agent.
If an oxidizing agent is present in the solution, aqueous potassium iodide will turn from colorless to brown.
In the presence of an oxidizing agent, a redox reaction occurs, turning the iodide ion in KI (which is colorless) to iodine, I2 (which is brown).
Define the term catalyst.
A catalyst is a substance which increases the speed of a chemical reaction, but remains chemically unchanged at the end of the reaction.
Define enthalpy change.
Enthalpy change is the amount of energy involved in a reaction.
Define electrolysis.
Electrolysis is the conduction of electricity by an ionic compound (an electrolyte), when molten or dissolved in water, leading to the decomposition of the electrolyte.
Why does an atom have a tendency to gain/lose electrons?
An atom that does not have a full valence shell will have a tendency to gain or lose valence electrons in order to achieve a stable electronic configuration.
Define isotopes.
Isotopes are atoms of the same element with the same number of protons but different number of neutrons.
State 3 factors affecting rate of diffusion.
Temperature, state of matter (gas/liquid/solid), relative molecular mass
List 3 examples of substances that sublimes.
Ammonium chloride, iodine crystals, dry ice, naphthalene.