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P1. Matter - Coggle Diagram
P1. Matter
Changes of state
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Solids most dense, then liquids, then gasses. 1cm^2 of solid has more particles then 1cm^2 of liquid or gas.
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Temperature - how hot/cold something is. Celsius/Kelvin/.Fahrenheit. Tells average kinetic energy of particle. Increase in heating can increase temp, produce change of state
Energy transferred from chemical to thermal store during heating. measured in joules. Energy depends on arrangement of particles and speed of vibration/moving. Increase in temp can cause chemical reactions
Specific Heat Capacity. Energy needed to raise temperature of 1 kg of material by 1 Kelvin/Celsius. Tells you how resistant it is to heating
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The Particle Model
Democritus + Leucippus. Atomos (indivisible). Ancient Greek philosophers. Could only cut paper up to a certain point, at which stage it will be impossible to cut any further
John Dalton. 1870's concluded that atom was a small indestructible sphere. Each element has a different type of atom. First to develop theory as provided explanation for his experiments
JJ Thompson. 1897. Investigating rays from hot metals NOT INVESTIGATING ATOMS. Cathode rays made of particles. <1/1000 of a hydrogen atom mass. Found particle called electron. Must have come from inside atom. Electron negative but overall positive. PLUM PUDDING MODEL 1904.
Ernest Rutherford. 1899. discovered alpha particles. Positive charge. Gold Foil Experiment. Marsden and Geiger fired alpha particles at gold foil. Unexplainable with Plum Pudding model. Tiny positive nucleus with smaller negative electrons. Mostly empty space
Bohr model. Adjusted Thompson model so electrons occupy orbits so they don't crash into nucleus. Improved on over past century
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Equations
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change in thermal energy (J) =
mass (kg) x specific heat capacity (J/kg°C) x change in temperature (°C). E = mcT
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