Senior 1 Chemistry Questions Chapters 1 and 2 .

Example: This is not a plus, there is no reason.

Example 1: If Na is Avogadro's constant, then the number of NH3 molecules contained in ammonia is , the number of hydrogen atoms contained in ammonia is , and the total number of atoms contained in ammonia is .

Example 2: In the mixed solution of MgCl2, Kcl and K2SO4 in 2L, if K+ is mol and Mg2+ is 3mol, find the concentration of K2SO4 substance?

Example 3: Under standard conditions, the mass of 100ml of a gas is: Calculate the relative molecular mass of this gas.

Example 4: A certain amount of liquid compound xy happens to be completely burned in a certain amount of O, and the equation for the reaction is:

xy₂（1）+3o₂(g)=xo₂(g)+2yo₂（g）

After cooling, the volume of the product measured under standard conditions is 672 ml, and the density is , then:

1. The volume of the former o is ———

2. The molar mass of compound XY is ———

3. If the mass ratio of X and Y in the XY molecule is 3:16, then the X and Y elements are ——— and ——— respectively

Example 5:11(20 minutes) At room temperature, dissolve CuSO4 5H2O in water to reach saturation, let the density of the solution be cm3, find:

1) The amount of Cuso4 in the solution.

2) The volume of the solution.

3) The amount of CuSO4 in the solution.

4) Take out ml of the solution and prepare a dilute solution of mol l, then what is the volume of the diluted solution ml?

Answer: 12 2g mol

4 672ml 76g/mol c s

5 mol mol /l ml

The molar volume of the gas under the standard condition is.

It depends on what state it is in, if it is under the standard condition, 1mol of H2 can be calculated using this formula, PV=Nrt, P represents pressure, V represents volume, N represents the amount of matter, R is a constant, I can't remember how much, T represents temperature.

However, the general questions are under the standard conditions, and there will be no non-standard conditions under normal circumstances.

The mass fraction of a substance is on the periodic table, but I can give you a few here. h1，he4,c12，n14，o16，na23,mg24,al27,si28,p31,s32,,k39,ga40,fe56,cu64,ag108

That's pretty much it.

Seeing that I've worked so hard, would you like to give me a share?

There is 1 mol of chloride in 1 mol of NaCl.

There are 2 mol chloride ions in 1 mol of mgcl2.

The quantity and concentration of the substance are the same, and the volume ratio is the ratio of the quantity of the substance, so 1*3:2*4=3:4 The second question is the reverse solution.

1.Let the concentration of sodium chloride and magnesium chloride be 1mol L, obtained by C=NV, the concentration of chloride ion substances in sodium chloride and magnesium chloride is 3 and 4 respectively, so the ratio of the amount of chloride ion substances in the two solutions is 3:4.

2.The same goes for 3:2:3

If you don't understand, you can ask.

Seek the best.

The ratio of chloride ions in the volume of sodium chloride (NaCl) and 2A volume of magnesium chloride (MgCl2) is 3A:2A*2=3:4

The ratio of chloride ions in the volume of sodium chloride (NaCl), 2A volume of magnesium chloride (MgCl2) and A volume of aluminum chloride (AlCl3) is 3A:2A*2:A*3=3:4:3

1. From n = CV, one mole of sodium chloride contains one mole of chloride ions, and one mole of magnesium chloride contains two moles of chloride ions, so that 3 volumes of sodium chloride contain 3c moles of chloride ions, and 2 volumes of magnesium chloride contain 4c moles of chloride ions.

2. The same solution is explained by the above analysis.

Get 3:4:3

First calculate the relative molecular mass of calcium chloride, that is, the relative molecular mass is equal to the sum of the masses of each atom = 40 + 37 + 37

Then calculate the amount of calcium chloride substance n = m m m

Then calculate the sum of the number of neutrons contained in a calcium chloride in the chemical formula = (40-20) + (37-17) + (37-17) = 60

So the amount of matter of the neutron is.

mol*60=180mol

The amount of sodium ions in the solution is the concentration of the substance.

The NaCl solution is correct and also the NaCl solution is incorrect.

Na2SO4 solution mol l Na2CO3 solution.

So it's a don't know how to ask.

This question discusses the concentration problem without considering volume, which is the interference information. It's easy to pick out A

I choose a...Their concentrations are the same.

The volume of concentrated sulfuric acid is: 100, because c = 18mol l, after dilution is 9mol l, that is, diluted 1 times, the volume should be 200.

If the density of dilute sulfuric acid is less than that of concentrated sulfuric acid, let the dilute sulfuric acid be x,x<

The mass of water added is: 200*x -100, x<, 200*x <200

The amount of water added is less than 100 mla

The density of concentrated sulfuric acid decreases as the concentration of the amount of the substance decreases.

When the density does not change with the decrease of concentration, the concentration should change to 9mol l when the same volume of water is mixed, but because the density also decreases after dilution, resulting in the expansion of the volume, the amount of water added should be smaller, answer a

Always remember that liquid volumes are not additive.

Another dilution that is commonly tested is to dilute concentrated ammonia. That density is just the opposite, and the higher the concentration, the lower the density.

The density of concentrated sulfuric acid is 1, so its volume < 100ml

The concentration of concentrated sulfuric acid is 18mol l, mixed with the same volume of water, and the concentration is reduced to 9mol l, so the volume of water added < 100ml

Only purple litmus solution can be used to separate nitric acid and sodium hydroxide first. Then take the remaining two and do a flame reaction. That's all there is to it, one solution, two methods. Wouldn't go against the topic, I used to do it.

1. A: The reagent taken out can be poured into the reagent bottle again to prevent contamination of the reagent in the entire reagent bottle.

B: Yes, the upper layer goes up, and the lower layer goes down to prevent pollution.

C: Sodium hydroxide is corrosive and needs to be weighed in a beaker.

d: Do not evaporate all the water during evaporation.

2. A: The preparation solution should be to add water to 1L, calcium chloride itself will cause volume changes.

B: The lower corner of chloride ions is marked as slow hand 2, and the concentration should be multiplied by 2c: after the concentration of the solution is prepared, no matter how much is taken, the concentration does not disturb the dislike of transportation.

D: Right.

Application: The quantity of matter can be used as a bridge to relate the mass of matter and the number of particles contained in the substanceExample analysis: The following statement is correct ( A 1g The number of molecules contained in hydrogen is na b The molar mass of sulfuric acid is 98g c 2mol The mass of hydroxide is 34g d The price molar mass of iron is equal to its relative atomic mass Analysis:

The number of atoms contained in 1g of hydrogen should be, i.e., a wrong; The unit of molar mass is g mol, b error; The molar mass of the molar dust and the relative atomic mass are two different physical quantities, and the molar mass of iron is equal to its relative atomic mass in g mol, d is wrong. The correct answer is c, the mass of hydroxide m = 2 mol * 17g mol = 34 g

Choosing d the same density and volume means that the mass is equal, and the molecular weight of these two gases is also equal, so choose D