Analysis of 15 questions in chemistry 5, analysis of 15 questions in chemistry

The question D examines the balance of matter, the balance of matter before the reaction, and the decrease of h after the reaction, the problem is to figure out how much h is reduced over there and how little there is. Got the problem. The amount of hydrochloric acid h substance m the amount of sulfuric acid h substance m 49

The amount of the substance of zinc is m 65 and the amount of the substance of iron is m 56

In this question, the iron is not fully reacted, and the zinc is completely reacted.

So, the amount of hydrogen produced on the hydrochloric acid side is determined by the amount of zinc as m 65, and the amount of hydrogen on the sulfuric acid side is determined by the amount of sulfuric acid as m 49

This question is to compare the sizes between them.

Hydrochloric acid edge acid excess so there is m greater than m 65 sulfuric acid edge iron excess so there is m 49 less than m 56 through the above two relations we can know the relationship between m and m from this comparison m 65 m 49

They are not sure.

All quantities in this question are calculated in units of h non-hydrogen).

The answer is that the reason is that zinc reacts completely, iron is surplus, and the specific conditions are as follows: 1. Acid reacts completely; 2. Zinc reacts completely, and acid also reacts completely; 3. The zinc reacts completely, and there is a surplus of acid reacting with zinc, and there is a surplus of iron in another beaker.

Analysis of Sun Liangming:

1) Incorrect, there is no change in pH, which proves that 84 disinfectant is not acidic, otherwise the pH will be reduced.

2) HClo + Naoh Naclo + H2O3) is unreasonable, and the phenolphthalein reagent discoloration slag sensitivity range is pH, and only red is displayed at pH.

Litmus reagent should be used, and the discoloration range is pH, and acidic, neutral, and alkaline are shown as red, purple, and blue, respectively.

4) The bleaching strength of 84 disinfectant is related to temperature or light intensity.

An appropriate amount of 84 disinfectant solution can be taken in a dark room and a bright room and gradually added to the NaOH solution containing phenolphthalein reagent.

Or an appropriate amount of 84 disinfectant can be taken in the refrigerator room and boiler room room and gradually added to the NaOH solution containing phenolphthalein reagent.

Combined with the environment, magnesium does not react with sodium hydroxide, and it is aluminum that does the negative electrode, but magnesium is more active than aluminum (metal activity order), so a is wrong. Since there is a lot of sodium hydroxide solution, the precipitation will not be seen immediately, so B is wrong. (The resulting aluminum hydroxide immediately reacts with sodium hydroxide) CD is not visible.

Aluminum and magnesium hydroxide solutions react to form tetrahydroxyaluminic acid and hydrogen.

NaOH absorbs carbon dioxide, i.e., produces carbon dioxide based on the combustion of methane, gets methane, multiplies, and gets liters.

The mass of the CO2-forming substance is.

The amount of CH4 and CO2 is equal, and so is the amount of CH4, and its volume is C.

The amount of methane matter = the amount of carbon dioxide substance =

Volume of methane =

Why do I feel more like a biology question?

1.The main ingredient of tofu is protein, and the coagulant is caso4 (gypsum)2Amino acid 3Pure.

c,b,a,d。The caustic soda is NaOH, the hydrated lime is Ca(OH)2, the quicklime is calcium oxide (CAO), the soda ash is sodium carbonate (Na2CO3), and the chemical composition of the active ingredient of Bordeaux liquid is CuSO4·XCU(OH)2·YCA(OH)2·ZH2O, a sky blue gelatinous suspension formulated from about 500 grams of copper sulfate, 500 grams of quicklime and 50 kilograms of water.

c g d a

I'm not sure.