Chemistry Flashcards
Hydrogen
H
Helium
He
Lithium
Li
Beryllium
Be
Boron
B
Carbon
C
Nitrogen
N
Oxygen
O
Fluorine
F
Neon
Ne
Sodium
Na
Magnesium
Mg
Aluminium
Al
Silicon
Si
Phosphorus
P
Sulphur
S
Chlorine
Cl
Argon
Ar
Potassium
K
Calcium
Ca
What is an element
A substance made up of only one type of atom
What is a compound
When two or more elements react in a chemical reaction the atoms don’t mix together, they become joined to one another to make compounds
List ways to identify if an element is metallic
Tend to be shiny (lustrous)
Are solid at room temp (except mercury)
Good conductors of heat and electricity. This means that they allow heat and electricity to flow easily through them
Can be bent and hammered into sheets (malleable)
Can be stretched into wires (ductile)
Give some examples of metallic elements
Aluminium, iron, mercury, gold and silver
List some ways you can identify an element is non-metallic
Tend to be dull
Don’t conduct heat or electricity. They’re insulators for electricity and heat
Break or crumble when bent (brittle)
What are minerals
Not chemically bonded
Can be made up of elements and compounds
Easily separated
Any combination of two or more elements or compounds
Define:
Solution
Solvent
Solute
Solution- a mixture in which one substance is dissolved in another
Solvent- a substance that dissolves another substance
Solute- a substance being dissolved
What is an alloy
A mixture of a metal with other metals and non-metals
Give some examples of alloys
Stainless steel- tools and cutlery
Brass- doorknobs, tap fittings, coffee pot
Solder- connect components in electrical circuits
Sterling silver- jewellery
What is a mineral
A naturally occurring chemical substance that hasn’t been made by an organism and that has atoms arranged into crystal lattices
Where are minerals found
Minerals make up most of the rocks found in the earths crust
Chemical composition
Mineral
A mineral has a definite chemical composition
How do identify mineral
Colour- many minerals have a similar colour
Lustre- refers to the way a mineral shines in reflected light
Vitreous = shiny luster
Metallic= metal
Dull = doesn’t reflect light well
Non-metallic = no shine
Streak- colour of its powder when rubbed on an unglazed white tile
Hardness- resistance of being scratched eg diamond = hardest mineral scale of hardness
What is an ores
Rocks that contain valuable minerals
What do geologists decide whether an ore is worth extracting
- quality of mineral
- size
- type of mineral
- demand
- protitability
- material surrounding the rock
Mineral exploration
Wha is aerial exploration
A quick way of exploring vast areas of land for mineral resources fairly quickly is to survey it from the using aircraft or helicopter
Give some methods of aerial exploration and explain them
Magnetic surveys
Magnometer- a device that measures the strength of a magnetic field.
Minerals containing iron, nickel or cobalt change earths magnetic field
Gravity surveys
gravimeters- a very sensitive instrument that measures small differences in the gravitational pull of the earth
Dense rocks and minerals affect the gravitational pull on the aircraft and gravimeters on board can detect this
Electromagnetic surveys
A survey that measures the effects of applying a magnetic fie,d to the earth
Detect ore bodies that are good electrical conductors
Seismic surveys
When a shock wave is sent into the ground surface, and the reflected sound waves are recorded
Geochemical surveys
Uses chemistry o show what minerals are presented
Rock and soil samples from the surface may be used but generally holes are drilled into the rocks
Satellite images
Satellites can take images of the earth using visible light and these other frequencies
images created using data from satellites that detect electromagnetic radiation ion from earth
What is physical change
A change that doesn’t result in a new substance being produced
Changing shape or form
A force is applied to break, bend, stretch, crush, twist or compress the object
These changes don’t produce new substances
Eg, when u squash a aluminium can it changes shape but it’s still made just of aluminium
What is expansion and contraction
Expansion- increase in size
Contracion- decrease in size
Physical changes can occur when the temperature of a substance increases or decreases
When solids, liquids and gases are heated, they expand. And the reverse for contraction.
Eg, hot air balloon use expansion of heated air to lift off the ground
When a substance expands, its volume increases and the atoms are spread further apart
What is melting
The change of state when a solid is heated and forms a liquid
What is freezing
The change of state from liquid to solid
Whys is evaporation
The change of state where a liquid changes to a gas at the surface of the liquid
What is condensation
A change of state where a gas is cooled and forms a liquid
What is mixing and give an example
The mixing of two substances is another type of physical change
Eg, peas and corn, they mix but no new substance are formed
What is dissolving and give an example
When a solid is dissolved in a liquid, they form a mixture
Although the solution looks and acts differently to the solute and solvent, no new substances are formed, for this reason dissolving is a physical change
Eg, when sugar dissolves in water
What is chemical change
A change that results in a new substance being formed
List ways to identify a chemical change
- change of colour
- a gas is given off
- a precipitate form (solid)
- energy is produced or given off
- seeing light or feelings change in temperature
What s the particle model
A simplified representation of solids, liquids and gases
Explain the arrangement of solids
The attraction between particles binds them together tightly
Solids are incompressible and hold their shape
The particles are fixed in positions but they vibrate on the spot
Explain the arrangement of liquids
The particles are packed tightly together, however they’re not stuck to each other as much as solids
Liquids take the shape of a container
Explain the arrangement in gases
Particles aren’t stuck to each other at all
Highly compressible
Move in straight lines until hey hit another particle or the side of a container
Changes of state in the particle model
Melting
Solid- particles vibrate, temp increases vibrations increase, and solid expands
Vibrations become so energetic that the attraction between particles can no longer hold the particles in fixed positions
Changes of state in the particle model
Freezing
Opposite of melting
As the free moving particles in the liquid are cooled, they slow and become less energetic
Eventually the particles are moving so slowly that the attraction between the particles is able to hold them in position and a solid is formed
Changes of state in the particle model
Evaporation
Occurs when particles in a liquid escape from the surface of the liquid to form a gas
As the liquid particles are heated they move faster until some are able to break free from the other particles at the surface of the liquid. The escaped particles have formed a gas. They’ve evaporated
Changes of state in the particle model
Condensation
When a gas is cooled
As temp falls particles gas move more slowly until forces of attraction between the particles stick them together. When the particles stick together, they form a liquid
What is a chemical reaction
The process of rearranging atoms in substances to form different substances
What is a word equation
A simple chemical equation where chemical s are represented by their names
What is combustion
Any chemical reaction where a substance burns in oxygen to produce light and heat
What is flammability
The chemical property of a substance that describes how easily the substance undergoes combustion
Give an example of combustion
Methane + oxygen > carbon dioxide + water
What is the word equation for photosynthesis
Carbon dioxide + water > oxygen + glucose
What is photosynthesis used for
Plants use the glucose produced by photosynthesis as food, to provide them with energy to live and grow
What is chlorophyll
The substance found in plant leaves green and collects energy from the sun for photosynthesis
Word equation for respiration
Glucose + oxygen > carbon dioxide + water vapour
What is corrosion
A chemical reaction that can cause damage to metals
Give an example of a corrosion equation
Iron + water + oxygen gas > iron oxide
What are monatomic element
An element that is made up of many individual atoms
What are molecular elements
Most non metallic elements are made up of molecules
Molecules are clusters of two or more atoms bonded together
Why are crystal lattices
Large grid like like structures that repeat the same arrangement of atoms over and over
Molecular formula
Number of atoms in a formular
What is the term for changing from a gas to a solid
Deposition
What is the term for changing from a solid to a gas
Sublimation
