P1- Matter Flashcards
What did daltons model show?
- all the atoms in an element are the same
- the atoms in one element are different from the atoms in all other elements.
- atoms were small indestructible spheres
What did Thompson find out about the atom?
- it contained a smaller particle called an electron
- he also found out that electrons were negative charged
What two ideas did Thompson have to make sense of?
- an atom contains negative electrons.
- Overall, atomes have no charge so they are neutral.
What was Thompson’s model called?
The plum pudding model
What did the plum pudding model consist of?
In this model..
- the atom consists of positive mass.
- there are negative electrons embedded in it.
- he did not know what the positive mass was made of.
What was the experiment Rutherford did?
- he found that some materials emit particles
- these alpha particles have a positive charge
- he fired them at a piece of gold foil
- some went straight through and some bounced back or deflected.
What did Rutherford conclude after his experiment?
- he suggested that the atom was made of a tiny positively charged nucleus.
- also that it was surrounded by electrons on the outside
- most of the atoms mass is its nucleus
What are the two types of particles in the nucleus?
- Protons
- Neutrons
In 1913, what did Niels Bohr suggest about the atomic model?
- in the Thompson model electrons were expected to spiral until they hit the nucleus.
- so he suggested that electrons can only move in fixed orbits called electron shells.
What is density?
- density tells you how much mass there is in a certain volume.
- density= mass/volume
- kg/m3
Why are solids denser than liquids and gases?
- particles are closer together
in 1cm3 of a solid there are more particles than in 1cm3 of liquid or gas.
What is the law of conservation of mass?
- if a material changes state its mass will not change if it is in a closed system.
- ie. when 1kg of ice melts you will get 1kg of water.
What is a temperature difference of 1 degrees Celsius in degrees Kelvin?
- the same thing as 1 degrees Celsius difference is equal to one degrees Kelvin difference.
What is 1 degrees Celsius in Kelvin?
-274 Kelvin
What is the difference between energy and temperature?
- The energy store depends on the arrangement of particles and how fast they are vibrating.
- temperature is the average kinetic energy of the particles.
What happens when you heat something up?
- change the energy stored and increase the temperature.
- could produce a change in state.
- cause chemical reactions to happen
What is the difference between a physical and chemical change?
- a chemical change isn’t easily reversible.
- a chemical change involved atoms breaking and making bonds.
- physical changes just rearrange particles and so they are easily reversible.
What affects the amount of energy needed to raise the temperature of a material?
- the type of material
- the mass of material
- the temperature rise
What is the specific heat capacity of an material?
-The amount of energy needed to raise the temperature of 1kg of w material by 1K
What is the equation for the specific heat capacity of a material?
- Change in thermal energy = mass x temperature change x specific heat capacity
What is the specific heat capacity of water?
4200 J/KGCelsius
What is the change of state from gas to solid?
Depositing
What is the change of state from solid to gas?
Subliming
What is the specific latent heat of fusion?
- the energy transferred when 1kg of a substance changes from solid to liquid state.
- or the opposite, liquid state to solid state.
