chemistry c1 Flashcards
(21 cards)
what are particles?
a tiny bit of matter
what is the particle model?
describes how particles are arranged and how they move in solids, liquids and gases
describe the arrangement and movement of particles in a solid
• arrangement is regular
• vibrate in a fixed position
• they are very close together
describe the arrangement and movement of particles in a liquid
• arrangement is random
• they are close together
• move around each other
describe the arrangement and movement of particles in a gas
• arrangement is completely random
• they are far apart
• move quickly in all directions
why can’t a solid or liquid be compressed?
there is no space for the particles to move into
what is a physical change?
•happens when a substance changes state, shape or breaks into pieces
• no new substances are made
• can be reversed
what is a chemical change?
• a change that produces one or more new substances
• irreversible
give an example of a physical change
freezing water to make ice
mixing sand with water
give an example of a chemical change
cooking eggs
steel rusting
what happens to particles during changes?
the particles stay the same but they’re arrangement and movement change
in a chemical change particles break up and then join together in different ways
what are atoms?
smallest particles that make up a substance
What are the forces between particles?
These are electrostatic forces of attraction between positive and negative charges.
How do the strength of forces between particles change with distance?
The forces become weaker the further apart the particles are.
In which state of matter are the attractive forces strongest?
They are strongest in solids.
In which state of matter are the attractive forces weakest?
They are weakest in gases.
what are the limitations of the particle model?
forces between particles
size of particles
space between particles
what is a molecule?
• made from two or more atoms joined together
• joined by attractive forces (chemical bonds)
what is the atomic number of an atom?
the smaller number
(number of protons)
what is the mass number of an atom?
the bigger number
(protons + neutrons)
what are isotopes?
atoms with the same number of protons and electrons but different number of neutrons
