Chem test revision

Standard solution

solution of precisely known concentration

Primary standard

substance used to make a primary standard solution

Secondary standard

a solution whose concentration has been previously determined via a separate titration

Titre

volume of the solution delivered from the burette to reach the end point of a titration

Titrant

is a solution with a known concentration that is added to another solution during a chemistry experiment called a titration.

Concordant titres

three or more titres that fall within approximately 0.1 mL of each other

Burette rinsed with water

Solution in burette becomes diluted
- Conical flask underestimated
- Burette overestimated

Pipette rinsed with water

Solution in conical flask becomes diluted
- Conical flask overestimated
- Burette underestimated

Conical flask rinsed with solution

Solution in conical flask has higher concentration

- Conical flask overestimated

- Burette underestimated

Overshooting the endpoint

End point + equivalence point discrepancy

Endpoint

point at which a colour change occurs during titration

Equivalence point

The point where a point at which the reaction has occurred as per the stoichiometric ratio of the balanced equation

Point of an indicator

to give a clear, visible sign—usually a change in color—when a specific condition in a solution changes

Assumptions of Kinetic Molecular Theory

- No volume

- No intermolecular forces
- No energy exchanged during collisions

Real vs ideal gas

• Real gases exist, ideal gases do not.

• Ideal gases have intermolecular forces, real gases do.

SLC conditions

25 degrees celsius (298 K) and 100kPa

Conversion between Pa, kPa, atm

100 000 Pa : 100 kPa : 0.987 atm

Molar volume at SLC

24.8L

C → K

+ 273

moles with SLC

n=V/Vm

ideal gas equation

pV=nRT, R=8.31

Greenhouse gases

CO2, H2O, CH4

Natural greenhouse effect

Greenhouse gases absorb infrared radiation to keep Earth warm

Enhanced greenhouse effect

The increase in human activity that leads to an abundance in greenhouse gases, leading to global warming.

requirements for primary standard

The substance must not react with the atmosphere e.g. moisture, carbon dioxide, etc. •
The substance must be soluble in solution. •
The substance must be readily available and inexpensive. •
The substance must be able to be weighed accurately - high molar mass