If you are interested in junior high school chemistry, please enter!

Interested, interested, o( o

The questions you asked were good, and the inference questions were extremely useful.

Elemental C, H2, N2, O2, I2, there are many compounds, the common ones are H2O, H2O2, CaCO3, KCL, Baso4, AGCL, etc.

Oxide, Fe2O3, FeO, Fe3O4, Cuo, MGO, H2O, H2O2, CaO, K2O, Na2O, Bao, CO2, CO and many more.

Common elements are Fe, Cu, C, O2

Common compounds FeO, H2O, CO2

The addition of vegetable oil to the test tube is generally used to isolate the air.

Elemental: C (black) Fe (black) Cu (red) O2 (colorless, odorless gas)...

Compounds: H2O, H2SO4, HCl, HNO3, CuSO4, BaSO4 (white precipitate), NaOH (deliquescent, corrosive), CaCO3 (white precipitate), Na2CO3...

Oxides: H2O, CO2, Co, SO2, Fe3O4 (black solid), Fe2O3....There are many more, according to the theme.

The function of adding vegetable oil to the test tube: 1. Prevent water evaporation.

2. Isolate oxygen (iron nail rust experiment).

3. The drainage method measures the volume of gas produced (measuring the volume of carbon dioxide produced).

In junior high school, 95% of the vegetable oil in the test tube is used to isolate the air and oxygen. As for the common substances, the upstairs has already made it very clear.

You know that you ask on knowing, why don't you know how to search on it.

Try to take them to do a little bit of experiment, let them do it themselves, and then explain the principle.

1. Start with interesting experiments to cultivate students' interest in chemistry learning Chemistry is a science based on experiments, experiments are a window for students to understand chemistry, and vivid demonstration experiments can best attract students' attention and stimulate their interest in learning. The instruments used in the magic wand lighting experiment are alcohol lamps, glass rods, 98% concentrated sulfuric acid, and potassium permanganate (KMNO4) powder.

The steps are to mix potassium permanganate powder and concentrated sulfuric acid in a crucible. Use a clean glass stick to light an alcohol lamp. Use a glass rod dipped in the prepared mixture to light the alcohol lamp.

ResultsA glass rod dipped in the mixture can light an alcohol lamp, and through this experiment, students will realize that it is not necessary to use a match, lighter, etc. to light an alcohol lamp. Certain substances react with each other to still ignite the alcohol lamp. Therefore, it can well cultivate students' interest in learning chemistry. Cultivate their hands-on ability, observation and experimental ability, and ability to analyze, judge and solve problems.

Then I held a glass of sodium hydroxide solution and a glass of colorless phenolphthalein solution in my right hand and deliberately told the students that these were two glasses of "clear water", and at this time told the students: "I want to turn these two glasses of 'clear water' into a glass of wine". So two glasses of the solution are poured together, and a bright red "wine" is immediately produced.

The students were overjoyed and surprised, and then the teacher asked, "Is there really wine in the glass?"

There is a way to teach, but there is no fixed law. The determination of teaching methods should be determined by the content of teaching materials, learning conditions, teaching resources and teaching equipment of the school. In the traditional teaching method, the teaching goal only focuses on students' cognition, ignores emotions, attitudes, and values, and cannot focus on students' development, and the interaction between teachers and students is not strong, which cannot promote the transformation of learning methods, which seriously restricts students' development and affects the formation of students' innovative spirit and innovative consciousness.