Unit 3 - Researching Chemistry Flashcards
What is gravimetric analysis
Technique through which the amount of an analyte can be determined through measuring
What to consider when suing a balance (4)
Clean balance
Dont lean on desk
Never weight anything hot
Never weight directly onto pan of balance
Weighing techniques
Weighing directly
Weighing by difference
Accurately approximately
What is weighing by difference
Weigh in one container then transfer to another
Whats accurately approximately
Mass must be close to instruction but must note actual mass used
Whats a standard soultion
Reference solution whose concentration is knows accurately
What requirements must primary standards meet
- High purity
- Chemically stable in air/ solution and normal T
- soluble in water
- high formula mass to reduce % errors in final c
Common primary standards
Oxalic acid for base titrations
Potassium iodate for redox titrations
EDTA for complexometric titrations
Silver titrate for gravimetric analysis/chloride solutions
How are solutions standardised
Titrating them against primary standard
Whats a complexion titration
Usually involves metal ions reacting to form metal complex
Similar to acid/base titrations
What is a back titration
Used when direct titration not possible or gives inaccurate results
Substance to be analysed is reacted eith an excess of another solution which can be titrated accurately
What is a colorimeter
Devicd ehich can measure the intensity of light transmitted through a sample solution at a particular wavelength
What is a calibration graph
Absorbance against concentration
What is a distillation
Used to separate two or mire substances if they have different boiling points
What do anti bumping granules do
Added to prevent a mixture ‘bumping’ and contaminating the distillate
