P1 Flashcards
What is the diameter of an atom?
1 ✖️10^-10 meters
Why was it named ‘the atom’ ?
Back then was known to be the smallest thing(particle ) in nature
What was dalton’s theory?
🟣🔵🔴🟢🟣🟡🔴🟣
Atoms are tiny INDIVISIBLE particles
All matter was made from atoms
Atoms in an element are identical, different for each element
Billiard ball
What was the cathode ray experiment?
Cathode rays = metal heated up inside a magnetic field
The discovery of electrons
They came from inside the particles (not indivisible)
What was the plum pudding model
Overall a neutral atom:
Random electrons in a
cloud of positive charge- evenly spread throughout
What was the gold foil experiment?
Alpha particles were sent through gold foil
99% passed though
1% of this deflected
What is an alpha particle
2 protons
2 neutrons
What was Rutherford’s model of the atom?
The atom is mostly empty space
The majority of the mass is looted in the nucleus
The nucleus is positively charged
⚛️⚛️⚛️⚛️
What was Bohr model of the atom?
He suggested that atoms move in fixed orbit around the nucleus,
Orbits = electron shellls
What is the size of the nucleus of the atom?
1 ✖️10 **-15 meters
What is orders of magnitude ?
The size relative to the power of (x)
What is density?
A measure of how much matter is contained within a given volume
What is the density formula?
Density = mass➗volume
Kg/m 3 =kg ➗m3
Why are solids more dense than gas?
Particles spread out more and therefore have a higher volume
What is temperature?
A measure of the average kinetic energy of particles in a substance
What is kinetic energy
How fast particles are vibrating/ moving
Measured in J - joules
What are the units of temperature?
*conversion of the two
Kelvin or Celsius
273k = 1 🅾️C
What are physical changes ?
Eg : changes of state & dissolving
No new matter is produced
Particles just arranged differently
Easily reversible
What are chemical changes ?
Eg : burning & chemical reactions
New substances are produced
Difficult to reverse
How do you measure the volume of an irregular object?
Fill the eureka can to the top
Place object in
Make sure the spout is n a measuring beaker
The amount on the beaker is the volume
What is specific heat capacity?
The heat energy required to raise the temperature of 1kg of a substance by 1 kelvin.
A.K.A : how easy or difficult it is to change the temperature of a substance.
The lower SHC means less energy is required
What is the specific heat capacity equation?
E = m ✖️S.H.C✖️temperature change(ø)
J= kg ✖️J/kgk ✖️K / °c
In the S.H.C practical, how could you have it more accurate/efficient?
Put a lid on
Use an insulating container
Add conducting gel between object and container
Submerge the heater fully
What is potential energy?
The energy used to change the position of the particles (changing state - intermolecular bonds)
What is specific latent heat the measure of?
potential energy
What is specific latent heat of fusion?
The heat energy transferred when 1kg of a substance changes from solid to liquid state
(Melting/freezing)
What is the latent heat of vaporisation ?
The heat energy transferred when 1kg of a substance changes from liquid to gas state.
(Evaporating/condensing)
What is the specific latent heat equation?
Energy = mass ✖️S.LH(v/f)
J= kg ✖️j/kg
E=ML
What is the equation for pressure ?
Pressure = force ➗area
Pa = N ➗m^2
How do gases exert pressure?
The particles move in high speed , random directions.
Collision with the walls of the container exerts a force- a net force on the inside of the container (surface) determines the pressure
How does temperature affect pressure?
The more temperature, the faster the particles move, the more frequently the particles collide with the container walls, the more force is exerted resulting in more pressure.
What was Rutherford expecting in his gold foil experiment?
He expected the alpha particles to pass right through as the positive charge was assumed to be spread out
How does temperature affect gas pressure?
As temperature increases particle have more kinetic energy. The particles collide with a greater force at the wall. Leading to a higher resultant force from the wall , leading to higher pressure.
The two are directly proportional as long as volume is constant.
what is the atmospheric pressure on earth?
100 kilo pascals
100,000 pascals
what is the relationship between the pressure and volume of a gas?
pressure and volume are inversely proportional as long as temperature is held constant.
on a graph the line would have a curved L but wouldn’t tough the axis of the graph
what happens to the pressure as the volume is halved?
the particles collide twice as often (as there is twice as less space between the particle and the wall. )
Therefore the force exerted by gas particles per unit of time doubles , doubling the pressure of the gas.
What is the equation for two variables of pressure and volume?
P1✖️V1= P2✖️V2
The product of pressure and volume stays the same before and after a change
What happens when a gas is compressed ?
A force is required to move the gas particles together.
Work= force ✖️distance
Therefore work is done on a gas. The particles gain kinetic energy , move faster, raise in temperature
What happens when a gas is expanded?
The gas particles apply a force, work is done (energy is transferred), the gas particles lose kinetic energy , move slower, a decrease in temperature
What is the earth’s atmosphere and why does it have it?
A layer of gases, near earth due to it’s gravitational field
What happens to the atmospheric pressure as you go higher up and why?
It decreases , because there are fewer gas particles due to it’s weaker gravitational field
Which state of matter has more potential energy?
Gas ,because it has weak intermolecular bonds. This means that a lot of energy has been transferred to it to weaken these bonds
Why is the pressure of a bottle highest at the bottom?
It has a large weight of liquid
How does pressure in a liquid vary with depth?
The pressure in a liquid ONLY depends on the depth below the surface.
More width, more mass of water, more weight, more force
Pressure and depth are directly proportional
How does the density of a liquid affect the pressure?
The higher the density , the more mass, the more weight force, higher force = higher pressure
What is the liquid pressure equation?
Ro GH
Pressure= density ✖️depth✖️gravitational field (10N/m)
Describe up thrust
A force that occurs whenever a body is immersed within a fluid.
Because of a pressure difference between the top and bottom fluid
What is the difference between the atoms and particles?
Particles can be atoms , molecules or ions.
An atom is a single neutral particle
Why do gasses have a low density?
They occupy more volume, as there is more space between the particles, as they have more energy.Resulting in a lower density
How does the depth affect the pressure?
More depth , means more mass, which earns more density, which means more pressure
What is archimedes principle?
The upthrust experienced by a body is equal to the weight of the fluid displaced
What is the formula for upthrust?
*upthrust is the weight of liquid displaced
Force = ro g h a
Force = density ✖️gravitational field strength ✖️height✖️surface area
Upthrust = ρghA
When will a body float, sink and rise
Float:
mg= ρghA
Rise :
Mg<ρghA
Sink:
Mg> ρghA
What happens when the atmospheric pressure is greater inside a ballon that it’s surroundings?
does density of water vary with height ?
NO, trick question . The density of water is constant.
The pressure increases tho
Under what circumstances will a body float?
Under what circumstances will a body sink
In circuit A , the total resistance is less than the smallest resistor value
In circuit B , the total resistance, is an addition of the two values of resistance
where does pressure produce a force?
the net force is produced at right angles to any surface
