Error-prone trap analysis is often used for changes in the state of matter
Trap one: Understanding of common white gas and white fogProne to error?
White gas, white fog is not water vapor, water vapor is not observable by the human eye, butWhite gas and white mist are small mist-like water droplets suspended in the airThe white gas and white fog we see in life are generally divided into two categories: one is the white gas emitted by hot objects, and the other is the white gas emitted by cold objects. They thoughIt is all liquefied by water vapor when it is cold, but the ** of water vapor is not the same. Don't mistake the white gas and white fog you can see for water vapor.
Trap two: Judgment of the change of the state of matterProne to error?
Six changes in the state of matter:Melting and solidification, vaporization and liquefaction, sublimation and condensationThere are many changes in the weather in life that belong to the change of the state of matter, for example, snow is formed by condensation, fog is formed by liquefaction, frost is formed by condensation, dew is formed by liquefaction, etc., some students are easy to confuse vaporization and liquefaction together, or write typos, such as put"Vaporization" is misspelled as "vaporization"., put"Melt" is misspelled as "melt.""
Trap three: MeltwithBoilThe condition is easy to understand.
It is believed that crystals melt when they reach their melting point, and liquids boil when they reach their boiling point
The melting point of ice is 0, and some students think that ice will melt when it reaches 0. In fact, the conditions for ice to melt are:(1) Reaching the melting point; (2) Continue to absorb heatWhen the ice cube is melting, if the heat source is removed, the ice cube will not absorb heat and will no longer melt. Similarly, similar conditions are required for liquid boiling: (1) to reach the boiling point; (2) Continue to absorb heat
Trap four: Ignores the effect of air pressure on the boiling pointProne to error?
Air pressure has an effect on the boiling point of liquids, and the air pressure in a pressure cooker is generally 12 standard atmospheres, the boiling point of water is close to 120. If you put a glass of 40 water in a vacuum hood and start pumping out, you will find that 40 water can also boil.
Trap five: The understanding of temperature and the reading of the thermometer are prone to errors
There is only a "high" and a low temperatureWe can say that an object has a low temperature, but we cannot say that an object has no temperature.
2.Thermometer readings are a prone point, and we canFind the position of the change mark firstThen, assuming that the temperature rises, determine whether the liquid level is close to or far from the zero line, if it is close it is now below zero degrees Celsius, if it is far away, it is now above zero degrees Celsius. Some students misread the temperature because they did not recognize the location of the zero tick line.