Encourage students to identify these and talk through possible explanations. Some prompts:. If needed, raise issues such as these, which will open up discussion, but it is better if the students themselves come up with some. Note that many of the issues are to do with gases — it is their properties that we most need a particulate model to explain.
To reinforce the notion of elastic collisions, ask what would happen if collisions between gas particles were not elastic. What practical consequences would there be for people?
This can be introduced by dropping different types of balls such as a soccer ball, a table tennis ball and a bouncy ball from toy shops and explaining that a bouncy ball behaves more like gas particles.
Using activities like POE Predict-Observe-Explain can help students think about and then question their existing ideas. The following activity will help students consider their ideas about the movement of particles. Set up two pairs of flasks each connected by a valve see diagrams below. Both pairs have brown nitrogen dioxide in the left hand side flask. The first pair also has air in the right hand side flask. Students are asked to predict what will happen when the valve between the two flasks is opened.
The brown colour will spread very slowly from one flask to the other because the particles have frequent collisions with the air particles. The second pair of flasks has brown gas in the left hand side flask but the right hand side flask is completely evacuated. Students are asked again to predict what happens when the valve is opened. The very fast speed of the molecules means that they fill the evacuated flask very quickly.
Diffusion experiments can reinforce the idea of movement of particles. These can also be used as POEs. Brownian motion can also be observed using stereo microscopes when sulphur powder or camphor is sprinkled on the surface of water or ethanol.
A cotton wool piece soaked in ammonia is placed at one end of a long glass tube with another soaked in hydrochloric acid HCl placed at the other end. Eventually a white ring will form where the two gases meet. The two gases are at the same temperature and thus the particles have the same kinetic energy; the ring forms closer to the source of heavier and thus slower moving HCl.
This is predicted by a comparison of the relative molecular masses. Including a strip of universal indicator paper in the tube allows the gas diffusion to be tracked.
Students need to be given the opportunity to use the scientific conceptions about particle theory in other settings. Our website uses a free tool to translate into other languages. Be detailed, please. A: The movement of the red particle is such where it only moves short distances in a straight line until it hits another particle; at that point, the particle then changes direction.
There is no predetermined path that the red particle travels. Each time the simulation is set, there is a different path that the red particle travels. NH3 aq 2 wide mouth gas collecting bottle with stoppers Procedure: 1. Have students observe the collisions of the marbles with each other and with the walls of the container. Simulate the effect of increase temperature by moving the box rapidly.
Have students not changes in the motion of the marbles. In a fume hood, place a small amount of 12M HCl in one of the wide mouth collecting bottle and stopper it. Place a similar amount of concentrated NH3 aq in the second collecting bottle and stopper it. Open both bottles in the fume hood. Carefully do this under a hood because these vapors are harmful. A: During these demonstrations you should have seen that with increase temp motion of hand moving the particles, the particles moved faster.
If all of the following flasks are the same size, at the same temperature, and contain the same number of molecules, in which flask will the pressure be highest? Flask 2 B. Flask 4 C. Flask 3 D. Flask 1 E. Ar :- He 3. Kr Gas pressure is caused by: A. If all of the following flasks are the same size, at the same temperature, and contain the same number of molecules, in which flask will the molecules be moving slowest?
Flask 2 C. Flask 1 D. Flask 3 Four different flasks contain gas samples at K. In which of the following samples will the gas molecules be moving the slowest? H2 :- CO2 C. Each of these flasks contains the same number of gas molecules. In which would the pressure be lowest? Flask 4 B. Flask 3 C. Flask 2 Which of the following gases would have the slowest rate of diffusion, assuming all of the gases are at the same temperature?
Each of these flasks is the same size and at the same temperature. In which flask will diffusion occur most slowly? Flask 3 9. Which one contains the fewest molecules? Flask 3 B. Flask 4 D. In which would the pressure be highest? Flask 1 C. Flask 2 D. Flask 3 Four different flasks contain gas samples at K.
In which of the following samples will the gas molecules be moving the fastest? CO2 Each of these flasks contains the same number of molecules.
In which container is the pressure highest? Flask 4 Which one contains the most molecules? Flask 2 :- Flask 4 C. Flask 1 In which container is the pressure lowest? Flask 1 B. If all of the following flasks are the same size, at the same temperature, and contain the same number of molecules, in which flask will the molecules be moving fastest? Flask 4 :- Flask 1 C.
Adding more gas molecules B. Decreasing the volume of the container C. Raising the temperature D. Using each site, answer the questions that I pose on the Google doc. Temperature is related to the average kinetic energy of the particles of the material. During a phase change, the temperature of the material is constant. For example, ice melts at zero Celsius. What does that imply about the average kinetic energy of the particles in each of the two phases?
Usually, adding heat to a substance causes the particles to increase in kinetic energy and the temperature rises. Since that does not happen during a phase change, where does the heat energy go?
A: Heat energy is used to change phases. Energy is needed to break the cohesion of particles of a solid so they become a liquid. Why is the energy needed to convert a liquid to a gas usually very much larger than the amount of energy needed to convert a solid to a liquid? A: The intermolecular bonds of a liquid are harder to break so more energy is needed to make a substance a gas. A radiator or pressure cooker allows a liquid to achieve a higher temperature than normal boiling by sealing off the system from the surroundings.
Based on the definition of boiling and this animation, how is that possible? A: If you change the pressure above the surface of a liquid, the boiling point can be changed as well. In addition, the temperature of the gas vapor can get much higher than the liquid. By sealing in the gases, you can continue to heat those gases to a higher temperature to cook the food. If all of the following flasks are the same size, at the same temperature, and contain the same number of molecules, in which flask will the molecules be moving slowest?
Each of these flasks is the same size and at the same temperature. Which one contains the most molecules? Which one contains the fewest molecules? In which flask will diffusion occur most slowly?
Four different flasks contain gas samples at K.
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