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Anonymous users2024-02-07Solution: (1) Copper does not participate in the reaction in the copper-zinc alloy, only zinc participates in the reaction, due to the complete reaction, then the mass of hydrogen gas generated is: 20g+
2) Let the mass of zinc in the copper-zinc alloy be x, and the mass of the generated zinc sulfate is y.
zn + h2so4 = znso4 + h2↑x y
65： 2=x ： 161 ：2=y：
Solution: x= y=
The mass fraction of copper in brass is: ( x100% =
The mass fraction of solute in the remaining solution is: x100% = A; Outline.
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Anonymous users2024-02-061) The copper in brass does not react with dilute sulfuric acid, so m zinc = 20+; m hydrogen =;
2)m Copper=, Copper=;
solute ZnSO4 in the remaining solution, mass m2=; Mass Score =
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Anonymous users2024-02-05The order of activity is known by zn>cu
By knowing the order of activity cu>ag
By knowing the order of activity cu>ag
By know the order of activity zu>cu
By knowing the order of activity zn>ag
Comparing the two pairs shows that 1 and 5, 2 and 3 will not work.
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Anonymous users2024-02-04Analyze and :
The verification is that the zn activity is greater than h and greater than cu.
The verification is that the zn activity is greater than the ag
A combination of both. It can be known that the activity of Zn is greater than that of Cu and Ag, but the activity of Cu and Ag is not known, so it cannot be verified.
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Anonymous users2024-02-03A combination of one and five. One phenomenon is that zinc reacts with copper and does not react, indicating that zinc is more active than copper. Five can prove that zinc is more active than silver. However, the sum of the two still does not prove that zinc and copper are lively.
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Anonymous users2024-02-021. According to the reaction of Zn with dilute hydrochloric acid and the non-reaction of Cu, it means that Zn H Cu;
Fifth, according to the solution of Zn and Agno3, the ag is replaced, indicating that the activity of Zn Ag is not compared with the activity of Cu and Ag, so the activity order of zinc, silver and copper cannot be verified.
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Anonymous users2024-02-01A group of Zn can react with hydrochloric acid to release hydrogen, while copper does not, proving that zinc is more reactive than copper. The third group of zinc displaces the silver, proving that zinc is more reactive than silver. But the combination of the two does not prove who is more lively, copper or silver.
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Anonymous users2024-01-31After seeing your question, I was a little overwhelmed, and I thought I was still the representative of the chemistry class back then, I was really ashamed!
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Anonymous users2024-01-30A mixture of elemental metals such as iron and copper
Substance elemental.
Non-metallic elements, such as oxygen, sulfur
Pure things {e.g. this line does not need to be written!}
Compound { as this line does not need to be written! }
For example, this line does not need to be written!
For example, this line does not need to be written!
1.Chemical properties of salt.
1) Salt + metal new salt + new metal displacement reaction, in which the metal that ranks first in the order of metal activity reacts with the salt solution of the metal that follows.
2) The reaction between salt and acid, salt and alkali, and salt must meet the conditions of metathesis reaction.
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Anonymous users2024-01-29Elemental metals such as copper, iron.
Non-metals such as oxygen, carbon.
Chemical properties of salt.
1.Salt + metal = new salt + new metal H (hydrogen) before salt solution 2No.
The direct copy-paster is my son.
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Anonymous users2024-01-28(2) The reaction of salt with acid, salt with salt, and alkali with salt must meet the conditions for the metathesis reaction to occur.
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Anonymous users2024-01-27Gases elemental, O2, H2
Non-gaseous elemental, K, Na
Salt, metal, front, exchange.
Salt and alkali, acid and alkali, produce salt and water.
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Anonymous users2024-01-26Let's ...
Because the solid matter is obtained after sufficient reaction, the reduced part is the mass of CO2, which is CaCO3===CaO+CO2
xg100/x=44/
x=10gcaco3%=10g/20g=50%
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Anonymous users2024-01-25The mass is conserved from the conservation of atoms before and after the chemical reaction, so m(b)=30g, m(a):m(b)=15g 1:30g 2=1:1
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Anonymous users2024-01-2445-15 = 30g (mass of all b's).
30 2 = 15g (relative molecular mass of b).
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Anonymous users2024-01-23From the conservation of atoms and mass before and after the chemical reaction, m(b)=30g, m(a):m(b)=15g, 1:30g, 2=1:1
According to "take the filter residue gram in step 1, add a sufficient amount of dilute sulfuric acid to fully react with the filter residue, filter, wash and dry to obtain solid grams", it can be seen that the solid gram is activated carbon that does not react with dilute sulfuric acid, then: (1) the total mass of iron and ferric oxide in the gram of filter residue is; >>>More
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