History of the Atom
Chemical Manufacturing
State Changes
Particle Model
Interpreting Graphs
Chemical and Physical Changes
100
What is the difference between solid sphere model and the plum pudding model?
Solid Sphere (Dalton -1803): recognised that atoms for one element are different to other elements
Plum Pudding (Thomson - 1904): recognised electrons are a part of atoms
100
What should chemical manufacturers think about when creating products?
Particle Model - solid, liquid, gas
Shape Change
100
What state has particles sliding past each other, by tumbling and rolling, does not have a fixed shape but DOES have a fixed volume?
Liquid
100
Which state of matter has the fastest moving particles?
Gas
100
What is the Independent Variable on this graph?
Time (hours)
100
Physical or chemical change? Why?
Physical:
- same state, no new substance, change in shape and size
200
What is the difference between the plum pudding model and the nuclear model?
Plum Pudding (Thomson - 1904): recognised electrons are a part of atoms
Nuclear Model (Rutherford - 1911): realised that there is a positive charge in the nucleus of an atom
200
I am a Chemical Engineer, and I am wanting to make a caramel-scented candle - what should I think about?
- Candle melting - state change - solid to liquid
- Gas being released from candle - liquid melting - going to gas
- Smell spreading - gas particles filling the space - increasing the energy of particles
200
What state has rapidly moving particles that are far apart, and does not have a fixed shape or volume?
Gas
200
How are the particles arranged in a solid, liquid, and gas?
Solid - close together and packed
Liquid - Slide past each other - still close
Gas - Far apart - moving rapidly
200
What is the dependent variable on this graph?
Distance (km)
200
What demonstrates that a physical change is occurring?
Change in:
- size
- shape
- state
- no new substance formed
- can be reversed
300
What is the difference between the Nuclear Model and the Planetary Model?
Nuclear Model (Rutherford - 1911): realised that there is a positive charge in the nucleus of an atom
Planetary Model (Bohr - 1913): proposed stable electron orbit, explained the emission spectra of some elements
300
What do manufacturers need to consider when producing a rose-scented perfume? In your response, refer to the particle model and changes of state.
Perfume particles are small and spread out easily in gases.
The liquid perfume evaporates into gas particles that move quickly and spread through the air.
Manufacturers need to make sure the scent evaporates at the right rate (not too fast, not too slow).
300
What state vibrates in place, has strong forces, and has a definite shape and volume?
Solid
300
What are the key components of the particle model?
- Matter is Made Up of Tiny Particles
- Particles are Always in Motion
- Particles Have Spaces Between Them
- Particles Interact with Each Other
- Energy Affects Particle Motion
300
Describe the trends of this graph from point to point:
A-B: as time increases from 0-5 hours, the distance increases by 3km.
B-C: Time is increasing from 5-8 hours, but the distance is staying the same (3km)
C-D: Time and distance increase rapidly from 8 to 12 hours and 3 to 12 km.
D-E: The graph plateaus, thus time increase (by 2 hours), but distance stays the same (12km)
E-F: The slope of the line rapidly decreases from 16 hours to 20 hours, over 12 kms
300
What is an indicator of a chemical change?
Change in:
- Colour
- Temperature
- A solid (precipitate) is formed
- Gas is produced (bubbles)
400
What is the difference between the Planetary Model and the Quantum Model?
Planetary Model (Bohr - 1913): proposed stable electron orbit, explained the emission spectra of some elements
Quantum Model (Schrodinger - 1926):
- Shows electrons don’t move around the nucleus in orbits, but in clouds with no foxed positions
- Still wildly accepted as most accurate model
400
When designing chocolate that melts smoothly in the mouth but not in your hand, what do manufacturers need to think about? Explain using the particle model and changes of state.
Chocolate needs to stay solid at room temperature (particles closely packed in solid).
It should melt near body temperature (particles gain energy and change to liquid).
Manufacturers control the melting point by adjusting ingredients and particle structure.
400
Explain why gases can be compressed but solids and liquids cannot.
The particles in a gas are very far apart, with large spaces between them. When pressure is applied, the particles can be pushed closer together, reducing the volume.
400
How does the particle model explain why gases spread out to fill a container?
Their particles are far apart and move quickly in all directions. Since they aren’t stuck together, they keep moving until they spread evenly through the whole space.
400
How far did the person/object travel in segment C to D?
9km
400
Is boiling water considered a physical change?
Yes - going form a liquid to a gas (state change)
500
What is the difference between the Solid Sphere Model and the Quantum Model?
Solid Sphere Model (Dalton - 1803):
- recognised that atoms for one element are different to other elements
Quantum Model (Schrodinger - 1926):
- Shows electrons don’t move around the nucleus in orbits, but in clouds with no foxed positions
- Still wildly accepted as most accurate model
500
What factors do manufacturers consider when making a deodorant spray? Use the particle model and state changes to explain how the product works.
Liquid deodorant is kept in the can under pressure so it stays as a liquid.
When you spray it, the liquid quickly changes into a gas and the particles spread out.
It evaporates fast, which makes your skin feel cool and helps the smell spread.
500
What is missing in this phase change diagram?
500
Compare particle movement in a liquid and a gas.
Liquid: Particles are close together but can slide past each other. They move more slowly than gas particles. This lets liquids flow and take the shape of their container, but they keep the same volume.
Gas: Particles are far apart and move very fast in all directions. They spread out to fill the whole container and can be compressed.
500
How is section A-B different from section D-E?
A-B: The two variables of time and distance are BOTH increasing.
D-E: Only time is increasing, distance is staying the same.
500
Is this a chemical or physical change? Why?
Chemical change:
- colour change: nail goes from grey to orange; solution goes from blue to yellow
- new substance has formed: the nail has rusted