Chemistry for junior 3, a method for comparing the activity of metals

If you want to compare the order of activity of the three metals, you can use the following method:

1.First, the three metals are arranged according to the order of metal activity.

2.Then you can take two sides of the metal, and in the middle of the metal salt solution, such as sulfuric acid or something. What to chlorinate. Nitric acid what.

3.It is also possible to use a salt solution on both sides, the method of intermediate metals.

It's very practical, our teacher summarizes it, shares it with you, and hopes you will improve, and other people's textbooks have it, such as this question.

The following reagents are selected, ** magnesium, zinc, iron three metal activity order, of which the group that can achieve the purpose is.

a, iron, zinc, magnesium sulfate b, iron, magnesium sulfate, zinc sulfate.

c, magnesium, iron, zinc sulfate d, iron, magnesium sulfate, zinc sulfate, sulfuric acid.

k ca na mg al zn fe sn pb ( h) cu hg ag pt au

1.The higher the position of the metal, the more active it becomes.

2.The metal in front of the hydrogen can displace the hydrogen in the acid, and the metal behind the hydrogen cannot replace the hydrogen in the acid.

3.Metals in the front can displace the metals in the back from the solution of their compounds, and vice versa.

Metals with strong metal activity can be displaced from compounds of metals that are weaker than them, such as Fe+CuSo4==Cu+FeSo4, where iron is more active than Cu. In junior high school, it is generally used in textbooks, and it is enough to memorize it.

k ca na mg al zn fe sn pb ( h) cu hg ag pt au

A solution containing a certain metal and a certain metal powder are poured together to react, and the metal powder is highly active.

Metals in solutions containing a certain metal that do not react are highly active.

1.It is easier to compare with some of its elements. Take oxygen, for example. 2.The metal is put into another metal salt solution (not suitable for active mg or more). See if you can replace it.

Quantify different metals in the same acid solution at the same concentration and compare the reaction rate.

1.The difficulty of reacting metal elements with water or acid to replace hydrogen.

2.Elemental metals are the most alkaline hydrates (hydroxides).

3.Elemental interpolar replacement.

Periodic table.

Metal Activity Order Table.

How easily a metal can replace hydrogen with acid or water.

The positive and negative electrodes of the galvanic battery.

Displacement reaction of metal salts. Wait a minute.

The difficulty of reacting metal elements with water or acid to replace hydrogen.

Elemental metal replacement.

Textbook tables of the order of metal activity and the accumulation of peacetime.

Summary. The strength of the activity of the metal: the shorter the reaction process, the stronger the activity of the metal, if the valence of these two metal elements in the compound is the same, the relative atomic mass of the metal can be judged according to the amount of hydrogen

The larger the relative atomic mass, the less hydrogen you get, and the smaller the relative atomic mass gets the hydrogen, they all have different valencies, then you can directly know the relative atomic mass, but there are two variables in your question, which is not easy to compare.

A question in junior high school chemistry about the understanding of the concept of metal mobility. In junior high school chemistry, there is a question about the activity of metals, such as a question, in which a sufficient amount of metal is added to the same amount of acid, and a graph is drawn according to the description, the ordinate of which is the mass of hydrogen and the abscissa is time. When teaching this section, our teacher said that there is a law here, judging the activity of metals according to the slope, the greater the slope, the stronger the activity of the metal, then here I have a question, if, magnesium, aluminum, zinc, three metals are put into dilute hydrochloric acid, then according to what our teacher said, magnesium should be on top of aluminum, however, the valency of aluminum is higher, two aluminum atoms can be replaced by three hydrogen molecules, which is equivalent to, one aluminum atom, can be replaced with a hydrogen molecule, given a metal, Its activity is a little higher than that of aluminum, but the valency of this metal is positive bivalent, then, a metal atom can be replaced, a hydrogen molecule, is there a possibility, because the activity of this metal is only a little higher than aluminum, but the molecular weight of the replaced hydrogen is quite different, will this lead to the image of this metal per unit time, will it be higher than aluminum?

Wouldn't this go against the rules of our teacher?

Metal Activity Order: Potassium, Sodium, Calcium Magnesium, Aluminum, Zinc-Iron, Tin, Lead (Hydrogen) - Copper, Mercury, Silver, Platinum The biggest effect of the metal activity order is that the highly active metal can be replaced by the less active metal from the salt. Moreover, the more active the metal, the more reducible it is, and conversely, the weaker the activity, the stronger the oxidation of its cations.

Thanks, but I mainly want to ask if it's possible that the kind of situation I've described.

I'm sorry, but I don't know much about that.

Oh, so I'll change the description:

There are two kinds of metals in a unit time, a metal is more active than a metal, but the valence of a metal is higher than that of a metal, so who produces more hydrogen per unit time, please write all the possibilities.

Of course, both metals react with acids.

The strength of the activity of the metal: the shorter the reaction process, the stronger the activity of the metal, if the valency of these two metal elements in the compound is the same, according to the amount of hydrogen, the relative atomic mass of the metal can be judged: the larger the relative atomic mass, the less hydrogen will be obtained, and the smaller the relative atomic mass will be the hydrogen, they are all different valencies, then you can directly know the relative atomic mass, but there are two variables in your question, it is not easy to compare. Okay

The activity of metals refers to how active they are in chemical reactions, i.e., their ability to react with other substances. Different metals have different activity, which can be represented by an order of activity. This order is derived based on the results of the reaction of metals with substances such as acids, water, oxygen, etc.

Generally speaking, the order of activity of metals is from high to low, and highly reactive metals have strong reducing properties and are often used to reduce other substances, for example, zinc can be used to reduce iron ions, while low-reactive metals do not have this ability, and their compounds are difficult to decompose by reducing reactions.

The following is the order of metal activity (from high to low) that is common in junior three chemistry:

Potassium > sodium> calcium> magnesium > aluminum> zinc> iron> tin> lead> hydrogen > copper》 mercury silver > platinum > gold.

Note that although hydrogen is not a metal, it is also listed in this order of activity. This is because hydrogen ions have some reducibility in acids, and it can form compounds with other metals or non-metals.

This sequence of activity is of great help in understanding the chemical reactions of metals, for example, in acidic solutions, highly reactive metals are able to react with acids to produce salts and hydrogen; Metals with low reactivity cannot react with acids. In water, highly reactive metals are able to react with water to produce hydrogen and an alkaline hydroxide; Metals with low reactivity do not react with water.

Order of Metal Activity:

Potassium, calcium, sodium, magnesium, aluminum, zinc, iron, tin, lead (hydrogen), copper, mercury, silver, platinum.

According to the order table of metal activity learned in junior high school chemistry, it can be known that all metals before hydrogen can be regarded as active metals, including potassium, calcium, sodium, magnesium, aluminum, zinc, iron, tin, and lead, and the chemical symbols are k, ca, na, mg, al, zn, fe, sn, and pd;

In the order table of metal activity, the higher the front, the stronger the activity of the metal.

The order of activity of chemical metals in junior high school is as follows:The order of metal activity is from strong to weak: k, ca, na, mg, al, zn, fe, sn, pb(h)cu, hg, ag, pt, au. <>

The higher the position of the metal, the stronger the activity, the easier it is to lose electrons and become ions, and the faster the reaction rate. The metal in front of hydrogen can replace the hydrogen in the acid, and the metal in the hydrogen behind the hydrogen cannot replace the hydrogen in the acid and does not react with the acid. The metal in front can be replaced by the metal in the back from the salt solution.

The metal in the back does not react with the salt solution of the metal in the front.

(1) Elemental metal + acid - salt + hydrogen (displacement reaction).

26.Zinc and dilute sulfuric acid Zn + H2SO4 = ZnSO4 + H2

27.Iron and dilute sulfuric acid Fe + H2SO4 = FeSO4 + H2

28.Magnesium and dilute sulfuric acid mg + h2so4 = mgso4 + h2

29.Aluminium and dilute sulfuric acid2Al2 +3H2SO4 = Al2(SO4)3 +3H2

30.Zinc and dilute hydrochloric acid Zn + 2HCl ==ZNCL2 + H2

31.Iron and dilute hydrochloric acid Fe + 2HCl ==FeCl2 + H2

32.Magnesium and dilute hydrochloric acid mg + 2HCl == mgCl2 + H2

33.Aluminium and dilute hydrochloric acid 2AL + 6HCl = = 2ALCL3 + 3H2

2) Elemental metal + salt (solution) - another metal + another salt.

34.Iron and copper sulfate solution reaction: Fe + CuSO4 ==FeSO4 + Cu

35.Zinc and copper sulfate solution reaction: Zn + CuSO4 == ZnSO4 + Cu

36.Copper and mercury nitrate solution reaction: Cu + Hg(NO3)2 ==Cu(NO3)2 + Hg

Carbon monoxide reduces iron oxide: 3CO + Fe2O3 High temperature 2Fe + 3CO2

Generally speaking, the activity of the elements in the periodic table from top to bottom and from right to left has an increasing trend, the essential reason is that with the increase of the metal radius, the number of electrons in the outermost shell decreases, and its ionization energy and sublimation energy decrease.

However, for some special cases, such as lithium, due to its extremely small radius, the heat of hydration is high enough to compensate for the lack of sublimation heat and ionization energy, resulting in its activity in water is even higher than that of cesium.

One influencing factor of free energy is the enthalpy change (h). When the metal element forms cations in water, it undergoes three steps of sublimation, ionization, and hydration, and there are energy changes in these three steps, which determines the enthalpy of the total reaction, which has a great impact on the activity of the metal. Therefore, when analyzing the causes of metal activity, it is necessary to comprehensively consider the sublimation energy, ionization energy and heat of hydration of metals [2].

The first can be verified with a displacement reaction, and the second is a comparison of the reaction rates of active metals and acids.

There are two metals, A and B, and the rate of hydrogen production is compared by putting a sufficient amount of A and B of the same mass into hydrochloric acid at the same concentration. The fast ones are more mobile.

Prepare the saline solution of A and B, put A into the saline solution of B, and B into the saline solution of A. If A is precipitated on B, then B is more active than A, and conversely, A is stronger than B.

If the metal does not react with the acid, use the second one.

Compare the rate of reaction with metals. The displacement reaction of a metal with a salt solution of another metal.

1. The alkalinity of the corresponding hydroxide of the metal.

2 The ease of replacing hydrogen in acid or water.

Metal Activity Order Table.

Mutual displacement of saline solutions

Example 1 (Binzhou 2010) X, Y, and Z are the three metals in the order table of metal activity, and they can undergo the following reactions in solution.

x+yso4=xso4+y y+2zno3=y(no3)2+2z x+h2so4=xso4+h2 z does not react with h2so4. then the activity of the three metals satisfies ( ).

a．x>y>z b．z>y>x c．y>z>x d．x>z>y

Analysis] This question examines the derivation of the order of metal activity based on actual reactions. Rule: The metal in front can displace the metal in the back from its salt solution, regardless of whether it is pre-hydrogen or post-hydrogen; The metal that precedes the hydrogen displaces the hydrogen in the acid.

According to the title, X can replace Y in Yso4, indicating that X is in front of Y in the order of metal activity, and Y can replace Z in Zno3, indicating that Y is in front of Z in the table of metal activity order. X can react with H2SO4 to produce hydrogen, while Z does not react with H2SO4, indicating that X is ranked before hydrogen and Z is ranked after hydrogen in the metal activity order table. Therefore, the order of metal activity of x, y, and z from strong to weak is:

x＞y＞z。then the activity of the three metals satisfies a.

Hopefully, there are exercises here that you want.