Science Yr 9 module 2 Flashcards
For memorising modules for assignments and exams
Who is Robert Brown and what is his significance in the discovery of particle/molecule movement?
Robert brown is a botanist who in 1827 discovered that pollen particles made a jiggling movement in water, later on naming his observation the ‘Brownian Motion’.
Do solid particles move around or vibrate on the spot?
Vibrate on the spot
Can liquid particles move around?
By sliding over each other
Can liquid particles be compressed?
No, because the particles are touching the neighbouring particles
Can liquid particles flow?
Yes, by sliding over each other
How many types of material does a substance have?
Only one
What is a molecule?
More than one atom chemically joined/bonded together
What is the name of when several of the same type of atom are joined together?
An element
What is the name of several different types of atoms are joined together?
A compound
What is sublimation?
When a substance (iodine + carbon dioxide for example) change directly from a solid state to a gas state
What are the 4 main properties that a type of substance depends on?
- Arrangement of particles
- Size and shape
- How strong the forces between the particles are
- How they move
What are the names of change of state?
Melting (solid - liquid)
Freezing (liquid - solid)
Boiling/Evaporation (liquid - gas)
Condensation (gas - liquid)
Sublimation (Gas to solid or solid to gas)
Can gas be compressed?
Yes, because it has lots of room the compress
Can gas flow?
Yes, because the particles can move around
What is diffusion?
The spreading of particles in a certain area from high concentration to low concentration
What are the three variables of diffusion?
Temperature, size and gradient
Aerosol
Small peices of solid or droplets of liquid suspended in gas
Brownian motion
A random jiggling movement of suspended particles in a liquid, making small collisions
Deposition
gas to solid
Endothermic
Transfer of energy from surroundings
Exothermic
The transfer of energy to surroundings
Subliming
solid to gas
Vapour
A gas phase of solid or liquid
What are atoms?
They make up everything, they are extremely small particles which are the building blocks of life
What are elements?
Made up of only one type of atom
What are compounds?
Two or more elements chemically bonded together
What are mixtures? and an example?
Two or more elements or compounds that are not chemically bonded together, (e.g air)
What are molecules?
Two or more atoms bonded together
Who dicsovered that the Brownian motion and what was the mystery behind the random movements?
Albert Einstein later on named this the Brownian motion, this was because of invisible water particles in the liquid moving the solid particles in different and random directions
What are the three states of matter?
Solid, liquid and gas
What type of gas is found in whipping cream?
Nitrous oxide (N2O)
What matter is always present in foam?
Gas
What is it called when you burn diesel and pieces of solid appear?
Particulates
What is deposition?
Gas to solid
What do melting points rely on?
How strong the forces are between the particles
What is the melting point of aluminium?
1538 degrees
What is the melting point of iron?
660 degrees
What is the melting point of zinc?
420 degrees
In an endothermic change does energy transfer from/to the surrounding?
from
In an exothermic change does energy transfer from/to the surroundings?
to
What does endothermic change include?
Melting and evaporating
What does exothermic change include?
Freezing and condensing
What year was it when scientists had discovered 60 elements in total?
1860
