Concentration Flashcards
what are the common concentration units?
- molL-1 (M)
- gL-1
what is a great solvent?
Water is a great solvent, so many things will dissolve in it!
what is a solution?
When solutes are soluble (dissolve) in a solvent a solution is formed.
characteristics of solutions?
Solutions are transparent and consistent throughout.
define concentration
Concentration is a ratio comparing the amount of solute to the amount of solvent in a solution.
what is a solution when it has a little solute?
dilute
what is a solution when it has a lot solute?
concentrated
How to express concentration?
Concentration can be communicated in a number of ways:
- Using colour for different concentrations (solute must be coloured)
- Using dots for different concentration solutions
- Using numerical values (with units)
concentration worded equation
Conc = amount of solute/amount of solvent
what are different ways to measure the “amount” of solute and solvent?
- using mass (g)
- using volume (L) or (mL)
- using moles (n)
- as percentages
what will using different amount unit do the concentration unit?
Using different “amount” units will change the concentration unit.
what is gL-1?
Conc (gL-1) = mass of solute (g)/volume of solvent (L)
C = m/V
when is gL-1 used?
These units are commonly used if the solute is a mixture (formula is not known) or for everyday life (non-chemistry) examples.
what is molL-1?
Conc (molL-1) = moles of solute (mol)/volume of solvent (L)
C = n/V
when is molL-1 used?
- Most common concentration units in chem!
- Solute must be pure (so the formula is known).
how are moles calculated?
n = m/M
how is molL-1 abbreviated?
Unit molL-1 sometimes abbreviated to M (Molarity)
what do you need to make sure when calculating concentration?
that the units are correct
what happens when salts dissolve?
When salts dissolve their ions become free to move in the solution.
what else can you calculate the conc of other than the salt?
Often we calculate the conc of the salt but you can also calculate the conc of either the + or - ions in the solution.
what does calculate the conc of ions in solution require?
This requires ratios to be considered.
where does water go in dissolving equations?
over the arrow
what are the new key glassware for a titration?
- volumetric flask
- conical flask
- pipette
- burette and stand
define standard solution
A standard solution is a solution (typically made of a dissolved ionic salt/acid/base) with an accurately known concentration.