C2 - Experimental techniques Flashcards
Which piece of equipment is used to measure time and what is the unit? [2]
- Stopwatch
- Seconds
What piece of equipment is used to measure temperature and what is the unit? [2]
- Thermometer
- Degrees in celsius
What piece of equipment is used to measure mass and what is the unit? [2]
- Mass balance
- Grams
Which pieces of equipment are used to measure volume of a liquid and what is the unit? [4]
- Measuring cylinder
- Volumetric pipette
- Burette
- Cm³
What piece of equipment is used to measure volume of a gas and what is the unit? [2]
- Gas syringe
- Cm³
What process is used to separate two or more solids that are soluble? [1]
- Paper chromatography
How do you calculate Rf values in paper chromatography? [1]
- Distance moved by solute divided by distance moved by solvent
Define a pure substance [1]
- A substance that contains a single element of compound not mixed with any other substance
Describe 3 ways the purity of a substance can be assessed [3]
- Melting point
- Boiling point
- Chromatography
Describe how melting/boiling point can be used to assess purity [2]
- A pure substance will have a sharp melting/boiling
- An impure substance will melt over a temperature range
Describe how chromatography can be used to assess purity [1]
- A pure substance will produce only one distinct spot on a chromatogram
Give two examples of purity of a substance being important [3]
- Manufacture of products used in;
+ Drugs
+ Food additives
What is a solvent? [1]
- A substance that dissolves a solute
What is a solute? [1]
- A substance dissolved in a solvent
What is a solution? [1]
- A liquid mixture composed of two or more substances
Define volatility [1]
- How easily a substance evaporates
Define solubility [1]
- How easily a substance dissolves
What is filtration used for? [1]
- To separate an insoluble solid from a liquid
What is the filtrate in filtration? [1]
- The liquid or solution that has passed through the filter
What is crystallisation? [1]
- When a liquid containing dissolved salt is evaporated, leaving the salt behind
What is distillation used for? [1]
- Separating a solvent from a solution
What is the difference between immiscible liquids and miscible liquids? [2]
- Immiscible liquids don’t mix
- Miscible liquids mix
How can immiscible liquids be separated? [1]
- By the use of a separating funnel
Why can fractional distillation be used to separate miscible liquids and gases? [1]
- Because different liquids and gases have different boiling points
