1.1: Elements Compounds and Mixtures Flashcards
What is Matter?
Anything that has mass and volume.
(Can be single chemical substances or a complex mixture of substances)
What are the 3 states of matter?
- Solid
- Liquid
- Gas
What are the 2 types of pure substances?
- Elements
- Compounds
What are the 2 types of mixtures?
- Heterogeneous Mixtures
- Homogeneous Mixtures
What is electrical conductivity?
Give an example
The ability to transmit electricity
Eg. Copper used in electrical wire
What is heat conductivity?
Give an example
Ability to transfer heat energy
Eg. Aluminium - saucepans
What is Density
Mass to volume ratio
Eg. Water - 1g/ml
What is refractive index?
And what is the value for water?
How light passing through a material is bent
Eg. 1.33 for water
What is malleability?
Ability to be shaped by hammering
Eg. Gold jewelry
What is Ductility?
Example
Ability to be shaped by pulling into a wire
Eg. Tantalum - dentists instruments
What are the two types of properties?
- Intensive
- Extensive
What are Intensive properties?
Those that do not depend on the amount of matter present.
- Can be used to identify substance
- Examples: density, colour, and boiling point
What are Extensive properties?
Those that depend on amount of matter present
Eg. Mass, volume, weight
What are Physical properties and what do they arise from?
Those observed by examining a sample of pure substances
Arise from:
1. Molecular structure
2. Strength of intermolecular interactions
What are Chemical properties and what do they arise from?
Those observed in the course of a chemical reaction
Arise from:
Distribution of electrons around the atom’s nucleus
Particularly outer (valence) electrons
What are the 4 properties of pure substances?
• Fixed composition
• Properties don’t vary
• Can’t be separated into simpler substances by physical methods
• Can only be changed by chemical reactions
Property of Elements
Cannot be split into simpler substances by a chemical reaction
Eg. Hydrogen, oxygen
What are Compounds made up of?
Made up of 2 or more elements (in fixed ratio) chemically bonded together.
Eg. Water 💧
What 2 things does Valency of an atom dictate?
- Combining power
- Interaction with other atoms
What is Relative Atomic Mass? (Ar)
Mass of one atom of an element / 1/12 the mass of Carbon-12
What is a molecule?
Two or more atoms held together by a chemical bond
What is Relative Molecular Mass (Mr) ?
Mass of one molecule of substance / 1/12 the mass of Carbon-12
What is a mixture and state its 3 properties
The physical combination of atoms or molecules
- Has variable compositions
- Mixtures with different compositions may have widely different properties
- They can be separated into pure substances using physical methods
What are the 4 properties of Homogeneous mixtures?
• Single phase
• Have the same properties throughout the mixture
• Uniform appearance
• Includes solutions
What are the 4 properties of Homogeneous mixtures?
• Single phase
• Have same properties throughout the mixture
• Uniform appearance
What are the 4 properties of Heterogeneous mixtures?
- Multiple phase
- Variable properties within a sample
- Non-uniform appearance
- Colloids are visually Homogeneous but microscopically heterogenous
What are the 4 properties of Heterogeneous mixtures?
- Multiple phase
- Variable properties within a sample
- Non-uniform ap
What are the 4 properties of Heterogeneous mixtures?
- Multiple phase
- Variable properties within a sample
- Non-uniform ap
How are mixtures separated?
Using their difference in physical properties.
How does crystallisation separate mixtures?
Select components by solubility
Solid from solution
How does filtration separate mixtures?
Selects components by particle size
Solids from liquids
How does extraction separate mixtures?
Selects components by solubility
Solid or liquid from solution
How does evaporation and distillation separate mixtures?
Selects components by boiling point
Solution or liquid from another liquid
How does chromatography separate mixtures?
Selects components by affinity for solid or mobile phases
