Gas presentation
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Throwing aerosol cans into a fire is dangerous because: 1) The high heat can cause the compressed gas inside to rapidly expand, which may cause the can to explode like a projectile. 2) The explosion could send flaming or molten fragments flying in all directions, posing burn and impact risks. 3) The contents of the aerosol can, such as propellants or solvents, may ignite or intensify the fire when exposed to high heat.
Gas presentation
- 1. Physics: study of the properties of matter that are shared by all substances.
- 4. What is gas? Gas - a substance that is characterised by: • widely separated molecules in rapid motion • No definite shape/volume – Expands to fill its container • Easily compressed (squeezed into a smaller container) – Compressibility is a measure of how much the volume of matter decreases under pressure – Gases are easily compressed because of the space between the particles in a gas
- 5. Common gases include - O2 and N2, the major components of "air" Other common gases - F2, Cl2, H2, He, and N2O (laughing gas)
- 6. 4 things You can predict the behavior of gases based on the following properties: pressure, P, Pascal's volume, V, litters. temperature, T, Kelvin's. number of particles, n, moles.
- 7. 1- Pressure and the number of molecules Pressure and the number of molecules are directly related: More molecules means more collisions. Fewer molecules means fewer collisions.
- 8. 1- Pressure and the number of molecules If you double the number of molecules, You double the pressure. As you remove molecules from a container the pressure decreases Until the pressure inside equals the pressure outside Molecules naturally move from high to low
- 9. The diagrams below show a sealed container at three pressures. Complete the labels showing the gas pressure in each container. What can happen if too much air is pumped into a tire?
- 10. 2-Changing the size of the container In a smaller container: Molecules have less room to move. Hit the sides of the container more often. As volume decreases pressure increases.
- 11. 2-Changing the size of the container As the pressure on a gas increases the volume decreases. Pressure and volume are inversely related. pressure volume
- 12. In the diagram, complete the labels showing the pressure on the piston and the gas pressure inside the container. When the volume is reduced by one half, what happens to the pressure? ………………………… ………………………… ………………
- 13. 3- Temperature Raising the temperature of a gas increases the pressure if the volume is held constant. … why? The molecules hit the walls harder.
- 14. 3- Temperature Raising the temperature of a gas increases the if the volume pressure is held constant.
- 15. Work sheet Work instructions Complete this work sheet. You are going to work in 4 teams of 3 students each. Your answer must be in cloze in this words : {direct – inverse- increase – decrease} you can use a word more than one. We have 10 minutes to run the activity.
- 16. Work sheet 1. If the temperature is constant, the relationship between pressure and volume is………. 2. If the pressure is constant, the relationship between temperature and volume is………….. 3. pressure of gas increased and its volume remains constant, its temperature will ………………… 4. If a gas volume is decreased and pressure, its temperature will ………………… 5. If the temperature of a gas remains constant but pressure is decreased, the volume will………… 6. Raising the temperature of an enclosed gas causes its pressure to …………… 7. If too much air is pumped into a tire the pressure will ………….
- 17. Explain why it is dangerous to throw aerosol cans into a fire.