Chemistry questions on chemistry enthusiasts.

1) If magnesium reacts completely with 500ml of 3mol l of sulfuric acid, then 36 grams are needed.

If aluminum reacts completely with 500 ml of 3mol l of sulfuric acid, then 27 grams are needed.

Obviously, magnesium-aluminum alloy cannot fully react with sulfuric acid.

The remaining sulphuric acid consumes Naoh

Eventually, SO42- is Na2SO4, so magnesium, aluminum, and sulfuric acid consume 3mol of NaOH

So the remaining unreacted NaOH is: 400ml * 8mol - 3 = because there is only one precipitate indicating that this NaOH reacts with Al(Oh)3 just completely so the mass of Aluminum is then the mass of Magnesium is , and its mass fraction is.

This is the case where aluminium can be less or none, so the mass fraction of magnesium ranges from 100%2) from (1) it is known that NaOH is left, and the gram precipitate must be a mixture of the two precipitates.

Then let magnesium be x mol and aluminum be y mol

i.e. there is 24x + 27y =

58x + 78(

The solution is x= y =

So the mass of magnesium is gram and the mass fraction is =

Overall. Suppose sulfuric acid and sodium hydroxide react.

The equivalent of sodium hydroxide added to the primary alloy is obtained.

If there is only one precipitate, it should be magnesium hydroxide.

The magnesium content should be at least that's it.

The quality has changed.

So it's the hydroxide that the alloy is bonded to.

Converting the valency of aluminum to 2 valence, the atomic weight of aluminum is 18 and the atomic weight of magnesium is 24

A classic chicken-rabbit cage problem.

n23h2

2NH3 starts.

Invert. x3x balanced.

1-x3-3x

2x because of n in the gas mixture

The volume fraction is a%, so there is:

1-x1-x）+（3-3x）+2x

a%x=(4a%--1) (2a%--1)1) NH in the mixture

The volume fraction is: 2x

4--2xx100%=1--4a% (you substitute x into it) 2) The pressure in the container is (4--2x) before the reaction

The chemical formula of the H2 2. The chemical formula for the formation of solid C is NH3+HCl=NH4Cl

The chemical formula of is SO2

2。An excess of A is introduced into the caustic soda solution and the ionic equation for the reaction that occurs is H2S+2OH-=S2-+2H2O

3。Two strong acids can be formed by fully reacting Y with an aqueous solution in (1) to form two strong acids, and the chemical equation of the anti-Qi response is S+3Cl2+4H2O=6HCl+H2SO4

Find the amount of matter first.

The amount of substance of water is.

The amount of sulfuric acid is.

1.Therefore, the ratio of the number of molecules of water molecule to sulfuric acid molecule is 3:2, and the amount of oxygen atom in water molecule is.

The amount of the substance of the oxygen atom in the sulfuric acid is.

2.Therefore, the ratio of the number of oxygen atoms in the water molecule to the sulfuric acid molecule is 3:83Water molecules contain oxygen atoms, which are combined.

The sulfuric acid molecule containing oxygen atoms is combined.

The amount of the substance in grams of water is:

That is, the ratio of the number of water molecules to sulfuric acid molecules, that is, the ratio of the amount of matter 3:2 The ratio of the number of oxygen atoms in the water molecule to the sulfuric acid molecule is (:(8 moles of oxygen atoms in water? Together.

Is sulfuric acid molar with oxygen atoms? Together.

H2O is.

H2SO4 is.

The ratio of the number of water molecules to sulfuric acid molecules is 3:2

The ratio of the number of oxygen atoms in the water molecule to the sulfuric acid molecule is 3:8

Water contains, oxygen atoms contain sulfuric acid, and oxygen atoms are oxygen atoms in total.

Water is the first question, the ratio of the number of water molecules and sulfuric acid molecules is the ratio of the amount of matter, that is, 3 to 2 The second question, water contains oxygen atoms, and sulfuric acid molecules contain oxygen atoms, so the ratio of the number of oxygen atoms is 3 to 8 The third question, the amount of matter has been calculated, as for the number, multiply the amount of matter by na=, water contains oxygen atoms, and sulfuric acid molecules contain oxygen atoms.

1 When you find that in humid climates, moss withers; The cedar has brown wounds, and the cotton leaves are whitish; That is, various plants appear "smoke spot disease". Excuse me if this is a sign of that gas contamination:

A SO22 What kind of gas pollution in the air does the appearance of "white spot disease" indicate that cloves and weeping willows are sluggish?

A SO23 According to the characteristics of air pollution in China, the items currently included in the air pollution index are not included:

a．co2 c.Oxides of nitrogen dTotal suspended solids.

4.Depending on the ingredients contained, the following are not the same type of "oil":

a Peanut oil bRapeseed oil cShea dGasoline.

5.The ingredients that are not present in soy sauce are:

a Amino acids bSugars cTable salt dFatty acid.

6.The white powder outside the persimmon is:

a.Fructose powder bDextrose powder cStarch DSucrose powder.

7.Smoking is strictly prohibited in the workshop where flour is produced, and the main reasons are:

a fire prevention bPrevent cProtection of the environment dProtect workers from nicotine poisoning.

8.Combustible ice from the depths of the ocean, the main components are:

9.When raising fish with tap water, the water needs to be exposed to the sun for a period of time before being injected into the fish tank

a.Make the hardness of the water less bCauses hypochlorous acid to decompose in water.

c.Plays a bactericidal role dIncrease the amount of O2 in the water.

10.At present, some foreign experts believe that ( ) is the resurrection water:

a.Boiled water bCool boiled water cTea dMineral water.

What is the reaction product of hydrogen iodide gas with oxygen?

2 Na2O2 Deca2CO2 2Na2CO3 + O22*78g 2*1mol

78g x y

The column proportional solution yields x== y==

Oxygen quality is.

Therefore, 78GN2O2 can react with liter CO2 (under standard conditions) to produce O2 mass of 16g.

2CO2 + 2Na2O2 = = 2Na2CO3 + O278g The amount of the substance of Na2O2 = 78 78 = 1mol so 1mol CO2 is required to participate in the reaction.

So the CO2 volume of the reaction = =

The amount of O2 substance generated = 1 2 =

O2 mass = 32* = 16g

2Na2O2+2CO2=2Na2CO3+O2Na2O2:(78g 78)mol=1mol So CO2 is up to 1mol

Because under standard conditions, V(CO2) = can be generated because the molar mass ratio of Na2O2 to O2 is 2:1.

m(o2)=

2co2 + 2na2o2 == 2na2co3 + o2

If the amount of 78GN2O2 is 1mol, then the amount of O2 is 16g, the mass of oxygen is 16g, and the amount of carbon dioxide participating in the reaction is 1mol, then the volume is. The relationship between them is determined by their stoichiometric number.

78 grams is 1 mol of Na2O2

2na2o2+2co2==2na2co3+o22 2 1

1 x yx = 1 mol volume v = 1*

y = moles. Mass = grams.

Analysis: The mass of silver nitrate reacting with copper can be calculated from the weight gain of copper sheet, and the total mass of silver nitrate minus the mass of silver nitrate reacting with copper can obtain the mass of silver nitrate that generates silver chloride precipitate.

cu+2agno3===cu(no3)2+2ag δm340 152x

x=340*

Let the mass of barium chloride be a, the mass of silver nitrate reacting with barium chloride is y, the mass of aluminum chloride is b, and the mass of silver nitrate reacting with aluminum chloride is z

bacl2+2agno3===2agcl+ba(no3)2208 340

a yy=340*a/208

alcl3+3agno3===3agcl+al(cl)3510

b zz=510*b/

a+b=340a/208）+510b/

Solving a system of binary equations can be found as a and b as their respective mass fractions.

The amount of hydrogen is 15 ml*

So4 2- is completely precipitated, then the amount of the substance of aluminum sulfate is the amount of the substance of Al3+ in the aluminum chloride solution is.

The amount concentration of the substance is: