C1 Flashcards
What are the forces of attraction like and what is it’s arrangement in a solid
There are strong forces of attraction, holding them in fixed positions and a very regular lattice arrangement
How do solids move and why?
They don’t move, they keep a definite shape and volume unlike liquids
What do atoms in solids do?
They vibrate about their position
What happens when you heat a solid?
It vibrates more, as it get more energy, and can expand slightly, eventually it will melt
What is the force of attraction like in liquids?
there is some, not very strong, they can move past each other but tend to stick together
Do liquids keep shape and volume?
no to shape but yes to volume
How do liquids move?
They constantly move in a random motion
What happens when you heat and cool a liquid?
When you heat, it will get faster and expand slightly, eventually it could evaporate and become a gas. If you cool, it will freeze and become solid
What is the force of attraction movement like in a gas?
no force of attraction, they freely move in straight lines and collide
Do gases keep a shape of volume?
no they will always fill the container
What happens when gas particles bounce of the walls of a container?
they exert a pressure
How regular are gas particles movement?
irregular, they move constantly in a random motion
what happens when you heat a gas
atoms move faster and they either expand or their pressure increases
What happens when you cool a gas
it will condense and become a liquid
What is wrong with the particle theory model?
in reality, the particles aren’t solid and they aren’t spheres - they’re atoms, ions, molecules. It doesn’t give you an idea about the size of the particle or the space between them. There are no forces between particles
What is a physical change?
When a substance changes from one state to another, no new substances are made, they are reversible
What are chemical changes?
During a chemical reaction, bonds between atoms break and change places, so they rearrange to form different chemicals called the products
Who was John Dalton?
He described atoms as solid spheres, and different spheres made different chemicals
Who was J J Thompson?
He concluded that there were even smaller negatively charged particles called electrons in the plum pudding model. This has a positive mass dotted with negative electrons
Describe the Rutherford experiment and what happened
they fired positively charged alpha particles at a gold sheet, some of the of the particles deflected
What was the conclusion from the gold foil experiment
that there was a positive nucleus in the centre of electrons and there was space between them
Who was Niels Bohr?
He suggested that electrons were fixed in shells, and had a fixed energy
Why do scientists share ideas?
So other scientists can develop and test and improve theories
What are the 3 subatomic particles, their relative mass and charge
Proton (1 & +1), Neutron (1 & 0), electron (0.0005 & -1)
