Chemical Analysis Flashcards
(37 cards)
What is a pure substances in everyday language (wrong definition)
A natural substance that has had nothing added to it
What is the true scientific definition of a pure substance
Single element of compound that is not mixed with any other substance
Examples of pure substances and why
Diamond (C) it only contains carbon atoms
Oxygen (O2) only contains oxygen molecules
Glucose (C6H12O6) only contains glucose molecules
Why is orange juice a pure substance
Mixture of water molecules, citric acid molecules, vitamin C molecules, glucose molecules etc.
Why is soap not pure
It is a mixture of several salts made from different fatty acids
Why is milk not pure
It is a mixture of several substances including water, animal fats, emulsifiers, minerals etc.
Why is mineral water not pure
Because it is a mixture containing water molecules and different types of ions
Is the melting and freezing point of a substance the same
Yes
What happens to temperature when a pure substance changes state
It remains while it changes state
How is changing state different for mixtures than for pure substances
Mixtures change state over a range of temperature
Examples of useful uses of mixtures changing state over a range of temperatures
Salt water
Antifreeze
Petrol
How is saltwater useful
Salt can be put on roads to create a mixture with water that freezes below 0°C and can for example freeze between a range of temperatures such as -5°C and -10°C depending how much salt is dissolved. This helps preven ice forming on roads in winter. Salt water boils between 101 and 103 just saying. (Depending on how much salt is dissolved)
How is antifreeze useful
It is mixed with water in car radiators to stop the water freezing in cold weathers the melting point of the antifreeze is -13°C and that of water is 0°C. The mixture typically has a melting point between -30°C to -40°C depending how much antifreeze is used
Very useful mixture petrol detail
It’s a mixture of hydrocarbons and boils over a range of temperatures from about 60°C to 100°C. Each individual substance in petrol has its owner specific boiling point, but the mixture boils over a range of temperatures.
What is a formulation
A mixture that has been designed as a useful product
How is a formulation simply made
By mixing together several different substances in carefully measured quantities to ensure the product has the required properties
Examples of formulations
Alloys
Fertilisers
Fuels
Medicines
Cleaning agents
Foods
Paints
What are alloys and example
Specific mixtures of metals with other elements such as steel is a mixture of iron and carbon
Important properties of alloy
It is harder than pure metals
Each alloy designed to have specific properties for its use
Fertilisers use
Provides nutrients for plants to grow
Example of components of medecine and specific functions
Active ingredient - provides therapeutic effect
Coating - protects the medecine
Binder - helps hold tablet ingredients together
Example: aspirin tablets
Uses of alloys
In jewellery and coins
Example of alloy components and their functions
Gold - provides corrosion resistance
Copper - increased strength and endurance
Silver - enhanced shine and conductivity
Examples of components in fertilisers and its function
Nitrogen - promotes leafy growth
Potassium - enhances overall plant health
Magnesium - supports strong cells
