Chemistry unit examination questions in the second volume of Shanghai Education Edition, grade three.

Possible relative atomic mass: H- 1 O- 16 S-32 Zn-65.

1. Multiple choice questions (This question contains 10 small questions, each with 2 points, totaling 20 points. There are four options for each small question, only one of which meets the meaning of the question)

1. The substances in the kitchen are put into enough water and fully stirred, and the one that cannot form a solution is ().

A. edible oil B. white vinegar C. white sugar D. salt

2. The following statement about the solution is true ()

A. Even and stable liquids are all solutions.

B Under other conditions unchanged, the solubility of nitrogen decreases with the increase of pressure [source

C. saturated solution must be thicker than unsaturated solution.

D. oil stains on tableware can be washed off by emulsification of detergent.

At a certain temperature, there is a glass of salt water, and a small amount of salt solids at the bottom of the glass cannot be dissolved. Now put the fresh radish pieces in and leave them for a while. The following statement is wrong ()

A. the original salt solution must be saturated and dissolved. B. the quality of radish pieces must be reduced. The salt solids in the cup must be completely dissolved. The quality of the solution must be improved.

4. At room temperature, there are two bottles of potassium nitrate solution, one bottle is saturated (solute mass fraction is 40%) and the other bottle is 10% solution. In the following experimental operation, it is () that can't distinguish the two solutions.

A, adding a certain amount of water b and adding a small amount of potassium nitrate crystals.

C, slightly lowering the temperature d and evaporating a small amount of water at room temperature.

5. Prepare 500 g concentrated sulfuric acid and distilled water with the density of 1.84 g/cm3 and the mass fraction of 98% in the laboratory.

It is 20% dilute sulfuric acid. How many milliliters does it take to measure concentrated sulfuric acid with a measuring cylinder? ( )

A. 100 ml 54.35 ml B. 100 ml 55.5 ml

250 ml 54.35 ml 250 ml 55.5 ml

6. With 100g 10% hydrochloric acid solution, the method to double its solute mass fraction is ().

A. pour out half the solution.

B. the mass of solute is doubled.

C, mixing 100g 10% hydrochloric acid with 200g25% hydrochloric acid.

D, that mas of the evaporated solvent is half of that of the original solution.

7. At the temperature of 7.t℃, add 50 g of water into a beaker filled with 0. 15 g of hydrated lime, and let it stand after full vibration. There is still undissolved white solid at the bottom of the beaker. The following statement is true ()

A. When the supernatant becomes an unsaturated solution at high temperature, the solubility of hydrated lime is 0.3 g.

C. The mass of the solution in the beaker is less than 50.15g d. The mass fraction of solute in the supernatant is more than 0.3%.

8. The right picture shows the solubility curves of three substances, A, B and C. The following analysis is correct ().

At A 50℃, the solubility order of a, b A>B>C is a > b > C.

When 50℃, 50gA is put into 50g water, a saturated solution of A can be obtained, in which the mass ratio of solute to solvent is 1:2.

C, changing the saturated solution of c into unsaturated solution, and adopting a cooling crystallization method.

D. when the saturated solution of a, B>A=C C is cooled to 20℃ at 50℃, the solute mass fraction relationship of the three solutions is B>A=C.

At 9.20℃, 20 grams of four pure substances, A, B, C and D, were taken and added into four beakers containing 50 grams of water for full dissolution. The dissolution is as follows:

Material methyl ethyl propyl butyl.

Mass of undissolved solids/g 4.2 2 0 9.2

The following statement is true ()

A. The four cups of solution obtained are all saturated solutions. B. solute mass fraction d of the solution.

The solubility relationship of four substances at 20℃ is c > b > a > d.

D the mass of solvent in four cups of solution is: solution c > solution b > solution a > solution d.

10. Selection of saturated saline water commonly used in agriculture. Under the condition of constant room temperature, a small amount of solids will precipitate after the saturated salt solution is exposed to air for a period of time. Description of this process, the following image is correct ()

Second, choose the filling question (this question includes 5 small questions, each with 3 points, totaling 15 points. First, choose a correct option among A, B and C, and then add the matching answer in D, with 2 points for each question, and fill in 1 point).

1 1. The following substances can be dissolved in enough water to form a colorless solution ().

A. ferrous sulfate B. sucrose C. flour D. _ _ _ _ _ _ _ _ _ _ _

12. With the device shown in the figure, drop X into solid Y, the liquid level in the U-shaped tube becomes higher on the right and lower on the left, and then

The reagent set corresponding to X and Y is ()

election

reagent

X. H2O H2O H2O

Y NaCl NH4NO3 NaOH

13 has a cup of saturated potassium nitrate solution at a certain temperature. To change the mass fraction of solute, the following operation is feasible ().

A. adding potassium nitrate crystal B. evaporating solvent at constant temperature C. cooling D. _ _ _ _ _ _ _ _ _ _

14. Now the NaCl solution with 5% solute mass fraction is prepared, and the following statement is correct ().

A. directly weigh the sodium chloride solid on the tray of the balance

B. The beaker for preparing the solution has residue after washing with a small amount of distilled water.

C, pour the prepared solution into a narrow-necked bottle, plug it with a cork, and label it.

D._______________________________________________

15. Use 10g water to evaporate100g saturated solution of sodium nitrate at 70℃, and return the temperature to 70℃. The following amounts have not changed ().

A. Solubility of sodium nitrate B. Quality of solute in solution

C. The quality of the solvent in the solution D. _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

Fill in the blanks and explain the problem (this big question contains 5 small questions, with a total of 30 points)

16.(6 points) Write the chemical formula of solute in the following solution:

Name of lime water potassium permanganate clarification solution

Solution physiological saline 38 "site" liquid diluted iodine sulfate

Chemical formula of solute

17.(7 points) Add 10g, 25g and 25g nano 3 solids into three beakers A, B and C with the same amount of water respectively, and after full dissolution, the phenomenon is shown in Figure 1.

(1) The solution in the beaker must belong to any one of _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.

(2) In Figure 2, the solubility curve of NaNO3 can be represented by _ _ _ _ _ _ _ _ (fill in "A" or "B");

(3) To make the remaining solids in beaker B continue to dissolve, the method that can be adopted is _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _;

(4) The meaning of point A in Figure 2 is _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _;

(5) At the temperature of T2℃, 30 grams of A is dissolved in 50 grams of water, and the mass fraction of the obtained solution is _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _;

(6) According to the analysis in Figure 2, if the saturated solution of 100g of A and B is cooled from t2℃ to t 1℃ respectively, the correct description of the obtained solution is _ _ _ _ _ _ _ (fill in the serial number).

A.A and b are both saturated solutions. B. solvent quality: a < b.

C. solution mass: A > B. D solute mass fraction: a > b.

18.(5 points) Complete the following questions as required:

(1) The above figure shows the solubility curves of solid substances A and B:

① The solubility of A and B increases with the increase of temperature, and the solubility is greatly affected by temperature.

② When t℃ is known, the solubility of substance A is wg. Then at t℃, the mass fraction of solute in the saturated solution of substance A can be expressed as%;

③ The solubility of gas is usually expressed by volume. For example, at 0℃, the solubility of nitrogen is 0.024. It means _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.

19.(6 points) The following table shows the solubility data of Ca(OH)2 and NaOH. Please answer the following questions:

Temperature/℃

Solubility/g Ca (OH) 20.190.170.140.120.090.08

NaOH 3 1 9 1 1 1 1 129 3 13 336

(1) According to the data in the above table, draw the solubility curves of Ca(OH)2 and NaOH. In the figure below, the solubility curve of NaOH can be represented by (fill in A or B).

(2) Turn a bottle of nearly saturated Ca(OH)2 solution into a saturated solution. The specific measures are as follows:

(1) adding calcium hydroxide, (2) raising the temperature, (3) lowering the temperature, (4) adding water, (5) recovering to the original temperature after evaporating water, and (6) adding quicklime.

Among them, the correct measures are. ?

A.②④⑥ B.③④ C.①③⑤⑥ D.①②⑤⑥？

(3) At 20℃, 19 1g saturated NaOH solution, after evaporating 10g water, and then cooling to 20℃, the mass of NaOH crystals can be precipitated as follows.

(4) The existing saturated solution of Ca(OH)2 at 20℃ (solution A) is obtained by adding a certain amount of CaO (solution B), and the mass fraction of solute in the solution is ethyl methyl (fill in ">", "

(5) The existing saturated solution containing Ca(OH)2 and NaOH at 60℃ should adopt the following physical methods to obtain pure NaOH crystals.

20.(6 points) The diagram on the right shows the solubility curves of substances A and B. Please answer the questions with this diagram:

At (1)℃, the solubility of A and B is equal.

(2) The substance whose solubility decreases with the increase of temperature is (fill in "a" or "b").

(3) The method of crystallizing and separating the substance A from the saturated solution is.

(4) At T2℃, respectively cool the saturated solutions of the two substances to t 1℃, and the solute mass fraction of solution A (fill in "greater than", "equal to" or "less than") is the solute mass fraction of solution B. ..

(5) Xiao Ming conducted the following experiment with substance A:

① During the experiment, the solutions corresponding to B, C and D are unsaturated solutions.

② In the process of adding another 30 g of solid A to the solution corresponding to B, it was found that all the solids were dissolved, and some solids were precipitated after a period of time. The reason why you think "all dissolved" is.

Four, experimental questions (this question includes 3 small questions, a total of 25 points)

2 1.(6 points) A beaker is filled with a certain mass of solution, the temperature is 80℃, and the solute is M. Put it in a room temperature environment, and measure the mass of solid M precipitated at different temperatures. The determination results are recorded in the following table.

Solution temperature/℃

Mass of precipitated solid M /g 0 0 2.0 4.5 8.4

If you don't consider the influence of water evaporation on the experiment, please answer the following questions.

Is the solution saturated at (1)65℃? _ _ _ _ _ (fill in "Yes", "No" or "Unable to judge");

(2) Turn the nearly saturated M solution at 40℃ into a saturated solution, and the following methods will certainly achieve the purpose of _ _ _ _ _ (fill in the serial number). (1) heating, (2) cooling, (3) adding solute M, (4) adding water, (5) adding another solid N, (6) evaporating water at constant temperature, and (7) mixing with saturated solution of M at 40℃.

(3) At 20℃, the solid powder M and water were used to prepare a 100g M solution with 5% solute mass fraction. The necessary instruments are: pallet balance (with weight box), beaker, _ _ _ _ _ _ _ _ _ _.

22.(5 points) The solubility curves of NaCl, KNO3 and Ca(OH)2 are shown in Figure 1 and Figure 2. Please answer:

Figure 1, Figure 2 and Figure 3

(1) As can be seen from Figure 1, the solubility of sodium chloride at 20℃ is g; Solubility of sodium chloride at 50℃ (fill in ">" or "

(2) In order to purify sodium chloride solid containing a small amount of potassium nitrate, the crystallization method can be _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

(3) As shown in Figure 3, at 20℃, put a small test tube filled with saturated limewater into a beaker filled with water, and after adding sodium hydroxide solid into the water, the limewater becomes turbid. Analyze the reasons with Figure 2.

23.( 14) The laboratory needs to prepare a certain concentration of potassium nitrate solution.

(1) Check the solubility of potassium nitrate. As can be seen from the right figure, the solubility of potassium nitrate is g at 20℃, and the mass fraction of solute is% when preparing potassium nitrate solution at this temperature (the calculation result remains an integer).

(2) calculation. Prepare 40 g of potassium nitrate solution with mass fraction of 10%, the required mass of potassium nitrate is g, and the required volume of distilled water is mL (the density of water is about 1 g/mL).

(3) Weighing. Put pieces of paper on the left and right plates of the balance respectively, and adjust the balance (fill in letters).

A. Move the traveling code to the required position first, and then add potassium nitrate until the balance is balanced.

B, first add the required potassium nitrate, and then move the code until it is balanced.

(4) measure. The instrument used to measure the required distilled water is (fill in letters).

(5) dissolution. Weighed potassium nitrate and distilled water are mixed and dissolved.

(6) dilution. 20 ml 10% potassium nitrate solution was diluted to 4% potassium nitrate solution at 20℃. Find the data you need from the table below: g/mL.

Density of potassium nitrate solution (unit: g/ml)

Temperature/℃

Mass fraction /% 20 40 60

4 1.023 1.0 16 1.007

10 1.063 1.054 1.044

V. Calculation problem (this problem includes 1 small question, with a total score of 10)

24. An extracurricular interest group in a school analyzed a batch of crude zinc samples (containing impurities, insoluble in water and not reacting with acid). Students in groups A, B and C conducted experiments respectively, and the experimental data were recorded as follows:

group

Medicine methyl ethyl propyl

Beaker+dilute sulfuric acid/g152.5152.5 252.5

Crude zinc sample /g 20 15 15

Beakers and residues/g172.1167.1267.438+0

Please analyze the data carefully and help them answer the following questions (each group answers completely):

The dilute sulfuric acid used by students in group (1) just completely reacts with the crude zinc sample;

⑵ Calculate the mass fraction of zinc in the crude zinc sample;

⑶ Calculate the mass fraction of solute in the original sulfuric acid solution;

(4) Calculate the mass fraction of solute in a group of experimental solutions that have just completely reacted (the beaker mass is 52.5g, and the calculation result is accurate to 0. 1%).

1 1 B NaCl, etc. Calcium carbonate hydrochloride 13. C adding water 14 C in order to speed up the solid dissolution, the mass fraction of solute in 15 A solution is stirred (reasonably) with a glass rod.

Fill in the blanks and answer the short answer (this question contains 5 small questions, with a total score of 30 points)

16 potassium permanganate c2h5oh H2SO4 naci2

17.①B； ②A； (3) heating (adding water); ④ The solubility of A and B is equal at T 1℃; ⑤33.3%; ⑥BD。

18.① Increase A2 100 w/( 100+w) ③ When the pressure is 1 kloc-0/kpa and the temperature is 0℃,1volume of water can dissolve 0.024 volume of nitrogen at most. (2 points)

19. (1) a (2) d (3) 9.1g (omitted units do not score) (4) < (5) cooling crystallization filtration (2 points).

20.( 1) t 1 (2) b (3) cooling crystallization (reasonable) (4) is greater than.

5] ① B ② When substance A is dissolved in water, it will release heat, which will increase the temperature of the solution and increase the solubility of substance A. ..

Four, experimental questions (this question includes 3 small questions, a total of 25 points)

2 1 (2 points per grid) (1) It is impossible to judge (2) 236 (3) Measuring cylinder and glass rod.

22(5 points) (1) 36 (2) < (3) Evaporative crystallization (4) Sodium hydroxide dissolves in water to give off heat, while the solubility of calcium hydroxide gradually decreases with the increase of temperature, so crystals are precipitated (2 points).

23 (2 dots per grid) (1) 3023 (2) 436 (3) a (4) BC (6)1.063

V. Calculation problem (this problem includes 1 small question, with a total score of 10)

24( 1) B

Solution: H2 is167.5-167.5438+0 = 0.4g.

XgZn reacts with YgH2SO4 to produce zgZnSO4.

Zinc+sulfuric acid = = = zinc sulfate+H2↑ =

65 98 16 1 2

X Y Z 0.4g

65:98: 16 1:2 = X:Y:Z:0.4g

Solution: x =13gy =19.6Gz = 32.2g.

(2) 13g/ 15g× 100% = 86.7%

(3) 19.6g/( 152.5-52.5)g× 100% = 19.6%