Calculation of chemical reaction This question has never been understood A. When B and C are 16 grams, they can only produce 30 grams of new substance D. if 10 grams of a is added, only C remains in the original substance after the translation stops 1 -- after the first reaction stopped, B remained 9g 2 -- after the second reaction, the mass of D is 50g 3 -- the mass ratio of a and B in the reaction is 3:2 4 -- the mass ratio of a to C in the reaction is 5:2 Please analyze each option carefully

First of all, a + B + C = 48g, after the reaction stops, adding a can continue the reaction, so a is insufficient. Let's look at the first option, because before and after a add 26G, b16g, and it is a complete reaction, so a: B = 13:8,... So 1 and 3 options are excluded. Because a: D = 16:30,..., the mass of d after the second reaction should be 48.75, according to a: B = 1

A problem of chemical reaction equilibrium
Under a certain temperature, the reaction takes place in a closed container
2A (g) + B (g) - (reversible) 3C (g)
If 2mol A and 2mol B are added at the beginning of the reaction, the volume fraction of a is a%
When other conditions remain unchanged, if the following four ratios are used as the starting material
The equilibrium of a is greater than that of A
A 2 mol C
B 2 mol a 1 mol B and 1 mol he (he does not participate in the reaction)
C 1 mol B and 1 mol C
D 2 moles a 3 moles B and 3 moles C
Please help me to analyze the next train of thought. Do not need specific calculation can also be

The answer is ab
C. Less than
D. The volume fraction of a is equal to the problem set,
Since the volume ratio of the two sides of the chemical formula is (2 + 1): 3, that is 1:1, the pressure will not cause the balance to move, as long as the ratio of a: B: C is analyzed. The higher the ratio of a, the greater the volume fraction of equilibrium

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