The answer to the second mode of Dongcheng

Volume 1 (multiple choice questions, 6 points for each small question, total 120 points)

1—5 DABCA 6— 10 CADDC 1 1— 15 ABCDB 16—20 AAACB

Volume 2 (multiple choice questions, total score 180)

2 1.( 18 points)

(1) ①14.45 ~14.50 (2 points) ②C(2 points) ③1.0/–1.02 (2 points)

(2)① Series connection (2 points); 1985(2 points) ② as shown in the figure (2 points) ③ as shown in the figure (2 points)

④3.80(2 points, giving 3.75 to 3.85)470(2 points, giving 458 to 475).

22.( 16)

(1) field strength between plates (4 points)

(2) Particles (2e, 4m) are subjected to electric field force.

particle acceleration

∵ level flat throw

(12)

23.( 18 points)

(1) The current direction in the excitation coil is clockwise. (3 points)

(2) The acceleration of electrons in the accelerating electric field is determined by the kinetic energy theorem.

①

Electrons move in a uniform circular motion in a uniform magnetic field, and Lorentz force acts as a centripetal force.

②

D=2r ③

Solution: ④

It's also B 5.

Alternative data: ⑥ (12)

(3) increasing the accelerating voltage; Reduce the current in the coil. (3 points)

24.(20 points)

(1) When the box is fixed, the elastic potential energy of the spring is released into the kinetic energy of the slider B, and the slider speed is set.

①

Time taken for slider B to reach A2 wall ② (4 points)

(2) A. Place the box on a smooth level ground. After the spring is released, the speed of the box and the slider B are set to V and V respectively, and the right side is the positive direction.

③

④

Solution: ⑤

⑥

Another solution: give up (6 points)

B when the slider b collides with A2 for the first time, the speed of the box becomes V 1, and the speed of the slider b becomes v 1.

⑦

⑧

Solution: pet-name ruby

⑩

Another solution: give up

From the results, we can know that after the collision of slider B and A2, the speed of slider B and box remains unchanged, but the direction changes.

Similarly, when the slider B collides with A 1, their respective speeds remain unchanged and only change direction. The slider b moves back and forth relative to the ground at a variable speed.

Time interval between two collisions of slider b

(1 1) (10 point)

25. (2 points for each space, a total of 14 points)

( 1) ; Ionic bonds and nonpolar covalent bonds; 2Na2O2+2CO2=2Na2CO3+O2 [Source: Subject Network ZXXK]

(2)& lt； ; & gt

(3) strong; Silica -3+ CO2 +H2O = CO2 -3+ silica (colloid)

26. (2 points per grid, total 12 points) [Source: subject network ZXXK]

(1)2-periodic VA family

(2)3Cu+8H ++ 2NO-3 = 3Cu 2 ++ 2NO ↑+ 4H2O； Sodium nitrite

(3)— 173.4kJ？ mol- 1； abdominal muscle

(4) 1:3

27. (Except for (2)② The second empty score of 3 points and 43 points, the others scored 2 points, totaling 16 points) [Source: Xue. Ke. Net Z.X.X.K]

(1)MnO2+4HCl (concentrated) MnCl2+Cl2 =+2h2o

(2)①c

②2fe 2 ++ Cl2 = 2fe 3 ++ 2Cl-； Take a small amount of the reacted solution and put it in a clean test tube, and add KSCN solution dropwise. If a red solution is generated, it is proved that Fe3+ is generated, and FeCl _ 2 and FeCl _ 2 undergo redox reaction (reasonable is fraction).

③Cl2+2 na2co 3+H2O = NaCl+NaClO+2 nah co 3

④ Connect a washing cylinder with sodium hydroxide solution behind device C (score if it is reasonable).

(3)35.75%

28. (2 points for each space, a total of 16 points)

(1) hydroxyl: hoch2-ch2oh+o2ohc-CHO+2h2o.

(2)CH2 = chch 2coo h； CH3CH=CHCOOH

(3)①

②

③

(4)

29. (2 points for each space, a total of 16 points)

(1) 2; d