Gas Laws and the Over-Reliance on Algorithmic Thinking | Chemical Education Xchange
Forget the fact that it's a complete misuse of Gay-Lussac's Law or the Students knew about the directly proportional relationship between .. We all want to teach our students to think critically. . What does it represent?. shown in Figure to study the relationship between the pressure and the volume of a gas. By taking Boyle's law states that the volume of a given amount of gas held at a con- P1 and V1 represent a set of initial conditions for a gas and P2 and V2 rep- resent a set of .. Thinking Critically Explain why gases such as. Gay-Lussac's law can refer to several discoveries made by French chemist Joseph Louis . Boyle's law – Relationship between pressure and volume in a gas at constant temperature; Charles's law – Relationship between volume and.
Neon is slightly lighter than air, Xenon is quite a bit heavier. Not actually a pure gas, but a gas mixture that acts much like a pure gas.
It is used by scuba divers at shallow depthsand to run pneumatic tools, and for producing foam materials. Laughing gas, Happy gas, Nitro, NOS Once used as an anaesthetic in dentist offices, this sweet-smelling gas reduces pain sensitivity and causes euphoric sensations.
It is an excellent oxidizer, reigniting a glowing splint much like oxygen would. Sulfur Hexafluoride One of the densest gases in common use. Summary 10 Textbook Assignments Read Chapter 1: Know the properties of gases Know the features of some important gases, esp: Oxygen Hydrogen Carbon dioxide Know the environmental problems associated with some gases, eg. The Kinetic Molecular Theory 2. The Kinetic Molecular Theory The Kinetic Theory of Gases tries to explain the similar behaviours of different gases based on the movement of the particles that compose them.
All matter is composed of particles ions, atoms or molecules which are extremely small and have a varying space between them, depending on their state or phase. Particles of matter may attract or repel each other, and the force of attraction or repulsion depends on the distance that separates them. Particles of matter are always moving. In other words, when it is cold, molecules move slowly and have lower kinetic energy. When the temperature increases, molecules speed up and have more kinetic energy!
In solids, the particles molecules are moving relatively slowly.
- Gases and Their Applications
- Gas Laws Boyle’s Law Charle’s law Gay-Lussac’s Law Avogadro’s Law
- Gay-Lussac's law
They have low kinetic energy In liquids, molecules move faster. They have higher kinetic energy. In gases, the particles move fastest, and have high kinetic energy. But, as we will find out later: Heavy particles moving slowly can have the same kinetic energy as light particles moving faster. Gas Particles move freely through container.
Gases and Their Applications - ppt download
The wide spacing means molecular attraction is negligible. Strong molecular attractions keep them in place. As they capture new electrons, the atoms emit light—they glow. Four of these are listed on page 61 of your textbook The fifth one is not. The particles of an ideal gas are in constant motion, and move in straight lines until they collide with other particles The particles of an ideal gas do not exert any attraction or repulsion on each other.
The average kinetic energy of the particles is proportional to the absolute temperature. Collisions between particles are perfectly elastic, ie. No energy is lost in collisions.
At absolute zero an ideal gas would occupy no space at all. Not all molecules move at exactly the same speed. The kinetic theory is based on averages of a great many molecules. Even if the molecules are identical and at a uniform temperature, a FEW will be faster than the average, and a FEW will be slower. That means SOME heavy molecules may be moving as fast as the slowest of the light ones. Temperature is based on the average mean kinetic energy of sextillions of individual molecules.
Not the velocity of individual molecules Not the mass of individual molecules.
Gas Laws and the Over-Reliance on Algorithmic Thinking
At that speed an oxygen molecule could travel from Montreal to Vancouver in three hours…If it travelled in a straight line. Each air molecule has about ten billion collisions per second 10 billion collisions every second means they bounce around a lot! The number of oxygen molecules in a classroom is about: The average distance air molecules travel between collisions is about 60nm. Because the distances between particles in a gas is relatively large, gases can be squeezed into a smaller volume.
Compressibility makes it possible to store large amounts of a gas compressed into small tanks 2. Gases will expand to fill any container they occupy, due to the random motion of the molecules 34 2. They do this because of the random motion of the molecules. Effusion is the same process, but with the molecules passing through a small hole or barrier Next slide: Which of the following samples of gas will have the greatest pressure if they all have the same volume?
Since we continuously try to connect the macro level with the particulate level, it served as a useful conceptual question. Instead, it just requires a moment in which you must stop and think about how the two variables, moles and temperature, relate to pressure.
After all, the idea of pressure came up frequently throughout the unit which meant we had multiple opportunities to explain why pressure would increase or decrease from a particle-level perspective. Within these opportunities, feedback was provided with the hope that it would be used to improve future explanations and overall understanding. In fact, I saw the majority of students citing the concept of particle-wall collisions much more frequently after they were given time to acknowledge previous feedback.
However, as I was grading the tests, I started to notice something—many students were choosing answers that I had previously thought would have been easily dismissed. After I was done grading the tests, I decided to look at the data. After reflecting on this for a bit, here is what I think happened and how it reflects a recurring issue especially in science education. Answer—10 moles at 70 0C Of all the answers available, I thought this one was going to be the easiest to dismiss.
After all, if answers A and B both had the same number of moles but one was at a lower temperature, how could the answer with a lower temperature possibly cause a greater frequency of collisions?
Gay-Lussac's law - Wikipedia
The bigger the bottom number temp the smaller the answer will be. Therefore, the smaller of these two temperatures will result in the greater pressure. My biggest concern here was that the moment they saw some numbers, they instantly resorted to an equation, which was completely misused.
So, what about the students that chose the other answer? Answer—2 moles at 82 0C I think the thought process that would lead someone to choose this answer is much easier to explain.