Chemistry practical: Concentration and preparation of solutions
solute
the substance that is dissolved
volume/volume % concentration
the volume is expressed in millilitres It can be used with liquid solutes
weight/weight % concentration
the weight of solute and the weight of solution are expressed in grams
use of density
we can use density to determine approximately the percent concentration of a solution
weight/ weight % concentration formula
weight of solute/ weight of solution *100
types of concentrations
weight/weight % concentration weight/volume % concentration volume/volume % concentration
normal concentration, normality
Normality is a type of concentration that shows the number of equivalents of a solute in one litre of solution which is used in analytical chemistry.
molar concentration formula
M= m1/Mr*V M= molarity Mr= relative molecular mass of solute V= volume of solution(l) m1= mass of solute (g)
mixing of solutions
Mixing of solutions is when a solution is prepared by mixing with another solution of the same solute or by diluting a more concentrated solution
Osmolarity (Osm/L)
Osmolarity is a type of concentration and is the number of osmoles in one litre of solution
Osmoles (osm)
Osmole is the number of moles of osmotic active particles
millimolar concentration (mM, mmol/L)
Shows the number of millimoles of a solute in 1 litre of solution and is used when the concentration of solute is low.
the amount of solutes can be expressed in what?
grams milligrams micrograms centimetre cubed moles
colligative properties
boiling point freezing point osmotic pressure vapour pressure
How can we determine the concentration of a solution
by measuring its density with areometer
molar concentration is used when measuring what?
colligative properties of solution
mass density (p)
mass density is the mass of 1L or 1mL of a given substance (solution). It's expressed in kg/m3 or g/mL
Density formula
mass of solution/volume of solution
Solution
solute + solvent
solution concentration
solution concentration is the amount of solute in a given amount of solution or solvent.
the amount of solute and solvent can be what?
the amount of solute and solvent can be 100g, 1mL 100mL 1000 mL
c1 c2 c3
the concentrations of the solutions we mix
An areometer consists of what?
An areometer consists of a tin of glass tube ending in a sphere
1 equivalent equals
1 mole of an ion divided to its charge.
Use of areometer
Areometers are used in brewing to test the strength of an acid in car batteries
dilution equation
C1V1=C2V2
molar concentration (Cm) formula
Cm= m1*1000/ m*Mr Cm= molar concentration m1= mass of solute m= mass of solvent Mr= relative molecular mass of solute
mixing equation
Cx= m1c1 +m2c2+ m3c3/ m1+m2+m3
Use of areometers in the lab
In lab practice they're used to determine the concentration of solutions
Number of moles
Mass / Mr
Solution
Solution is a mixture of 2 of more substances in a single liquid phase
Use of mg% or microgram %?
These types of concentrations are used in clinical labs in the blood and urine test and analysis of other biological liquid
When the amount of solute is small?
When the amount of solute is small, its concentration can be expressed as milligram percent concentration (mg%) or microgram percent concentration (yg%). The amount of solute is expressed in milligrams or micrograms and the amount of solution is 100g or 100mL.
areometer
areometer is an instrument based on Achimedes principle and is used to measure the relative density of liquids.
cross rule
cross rule is used when a solution is prepared from 2 solutions of one and the same solute different percent concentration
micromolar concentration
gives the number of micromoles of a solute in one litre of solution.
nanomolar concentration
gives the number of nanomoles of a solute in a litre of solution
relation between molar, millimolar, micromolar nanomolar and picomolar
mol/L= 10^3mmol/L= 10^6micromol/L= 10^9 nanomol/L= 10^12 pmol/L
molar concentration (M mol/L)
molar concentration is the number of moles of solute per litre of solution
molar concentration (Cm)
molar concentration shows the number of moles of a solute in 1000 grams of solvent
2 types of density used in practice
relative density (d) mass density(p)
relative density (d)
relative density is a digit that shows how much the weight of a given solution is bigger than the weight of an equal volume of water
weight/ volume % concentration
shows the weight of the solute in the total volume of solution. The volume is given in millilitres
solution density
solution density refers to the ratio between the weight and volume of a given solution
solvent
solvent is part of the solution that dissolves the solute
m1 m2 m3
the mass (in grams) of the solutions we mix
