The final examination paper of the first volume of the eighth grade

In 2005, Wenzhou City tested the academic level of the eighth grade of the new curriculum in the first semester.

Science Examination Paper (A) 2006 438+0

Congratulations on your completion of the science study in Grade 8 (1). This volume will test the teacher's teaching effect and your gains. Please read the questions carefully and answer them as required. The completion time of this volume is 90 minutes.

First, multiple-choice questions (2 points for each small question, ***50 points)

1. The main source of water for human production and life is ().

A, seawater B, groundwater C, terrestrial water D and atmospheric water

2. When electrolyzing water, the gas produced by the anode can rekindle the wood strip with Mars is ().

A, hydrogen b, hydrogen c, oxygen d, oxygen

3, the characteristics of the following animals related to increasing pressure is ()

This puppy has sharp teeth. The centipede has many feet in its abdomen.

C, loach body surface has viscous liquid D, snake body surface is covered with rough scales.

4. As shown on the right, where is the maximum pressure of the liquid at the bottom of containers A, B and C? ( )

A, point a, point b, point B.

C, point c and point d are the same size.

5, in the following chart, the use of buoyancy is ()

6, the following substances do not belong to the solution is ()

A, mineral water b, seawater c, iodine d and muddy water

7, about the solution of the following statement is correct ()

A saturated solution must be a concentrated solution.

B at t℃, the saturated solution of 100g of a substance contains 18g solute, so the solubility of the substance at t℃ is 18g.

C, saturated solution refers to a certain amount of solvent at a certain temperature can't continue to dissolve solute solution.

D. Unsaturated solution can be changed into saturated solution by adding solvent.

8, the main basis of atmospheric stratification is ()

A, vertical variation characteristics of air pressure B, vertical variation characteristics of air temperature

C, vertical variation characteristics of precipitation D, the above three are all.

9. The following phrase describing weather phenomena is ()

A, warm in winter and cool in summer; B, the seasons are like spring; C, it is very hot all year round; D, breeze and drizzle.

10, when does the highest temperature appear in a day? ( )

A, before and after sunrise b, at noon 12:00 C, 2:00 D, before and after sunset.

1 1. On the weather map, the wind direction shown on the right is ().

A, southeast wind b, northeast wind

C, southwest wind d, northwest wind

12, in pharmacy, in order to extract antibiotics from the solution, water should be boiled by heating to remove water, but the temperature above 80℃ can't extract antibiotics, and the method to be adopted is ().

A, increase the air pressure to make the boiling point of water lower than 80℃ B, and decrease the air pressure to make the boiling point of water lower than 80℃

C, shortening the boiling time d, and heating to boiling with low fire.

13. Hang two ping-pong balls in the air with a thin thread and keep a proper distance. When blowing hard between them, two table tennis clubs ()

A, separate to both sides b, move closer to the middle c, stay put d, can't judge.

14, the following phenomenon may appear in the low pressure area is ()

A, Wan Li is cloudless B, dragonflies fly higher C, rainy D, sunny and dry.

15, "Four seasons in one mountain, different days in ten miles" reflects that the main factor affecting climate is ().

A, latitude position b, land and sea distribution c, terrain d, human behavior

16, the following biological behavior, does not belong to the rhythmic behavior is ()

A. flowering and fruiting of plants B. owls catch voles at night

C. Migration of migratory birds D. Growth of plants behind stems

17, someone is slow-witted, mentally retarded and short stature, which is due to people ()

A, insufficient secretion of growth hormone in childhood B, insufficient secretion of insulin in childhood

C, insufficient thyroid hormone secretion in childhood D, insufficient sex hormone secretion in adolescence

18, the phototropism of plants is due to ()

A, the distribution of auxin on the smooth surface is more than that of B, but less on the smooth surface.

C, the distribution of auxin on both sides is as much as that of D, which is possible.

19. After the car accident, someone's coordination ability was greatly reduced. Please judge that the injured part may be ().

A, spinal cord B, brain C, brain stem D, cerebellum

20, the following options, belongs to human behavior is ()

A, strong light stimulation, immediately close your eyes B, hear the bell, walked into the room.

B, cannibalism, salivation D, hearing the tragic story makes people cry.

2 1, quiet, the main part of human heat production is ().

A, brain B, viscera C, muscle and skin D, others

22, the figure marked with a pencil of several materials, usually belongs to the insulator is ().

A, wood, rubber b, graphite, metal

C, wood, metal d, graphite, rubber

23, as shown in the four circuit diagrams, corresponding to the physical diagram is ().

24, as shown on the right, to make the sliding rheostat slide to the left when the resistance becomes larger, two wires in the circuit should be connected ().

a . c . d . b . a . d

C.c and b.d.a and C.

25. The factors affecting the resistance are studied by experiments. Teachers provide students with the following optional wire specifications, as shown in the table below. Do you think the reasonable choice of conductor is ()

a、abcd B、aefg C、bcfg D、cdef

2. Short answer questions: (65438+ 0 points per grid, ***35 points)

26. The picture on the right is a schematic diagram of the water cycle:

Write the names of the links shown in the water cycle:

(1)② Yes; ② ③ Yes.

27. A student prepared100g of 5% salt solution. The whole process is shown in the figure below.

Fill in the blanks as required: point out the other two steps of the experiment and point out the mistakes in the picture:

(1)① Step 1: Calculate that salt is gram and water is milliliter.

Step two: Step three:.

(2) Errors in the picture:

28. A metal ball is said to be 7.6 Niu in air and 6.62 Niu in liquid, so the buoyancy of the metal ball is cow, and the gravity of the liquid it displaces is cow.

29. The solubility curves of two solid substances drawn by Xiao Zhang are shown on the right:

At (1)40℃, the solubility of substance A is.

(2) The information you can get from the picture on the right is: (Write at least two)

A, yes;

B, B.

30. Due to the continuous development of modern industry, the gradual improvement of living standards, the massive consumption of energy such as coal, oil and natural gas, and the massive reduction of forests, the carbon dioxide in the atmosphere is increasing, and the heat preservation effect of the atmosphere on the ground is enhanced, which makes the global temperature warm.

(1) The main reason for the earth's "sweating" is the increase in the mass fraction of carbon dioxide in the atmosphere caused by natural and man-made reasons. There are two reasons for the increase in the mass fraction of carbon dioxide:

; .

(2) What measures do you think should be taken to reduce carbon dioxide emissions?

.

3 1. The picture on the right shows the weather map of the northern hemisphere. Please answer the following questions:

(1) A is controlled by air pressure, and the weather conditions are characterized as follows.

(2) The active front near the top and bottom is the front, and the temperature at the top and bottom will decrease after the front passes through the top and bottom.

32. In general, the hand will retract quickly when it comes into contact with a hot object, but this is not always the case. For example, in order to rescue people trapped by the fire at the scene of the fire, firefighters sometimes touch high-temperature objects with their hands and persist for a period of time. At this time, it is a conscious behavior involving the brain, indicating that the brain is the nerve center of _ _ _ _ _ _ _ _, which can be the lower nerve center below the brain.

33. After a normal meal, the blood sugar content of Party B is 14%, and that of Party A is 0. 1%. Then two people, A and B, were injected with the same amount of glucose solution with the same concentration, and their blood sugar content was measured every half hour. The result is shown in the curve on the right. Please answer:

(1)A and B are patients, and they may have _ _ _ _ _ _ _ _.

(3) After drinking glucose solution 1 hour, the blood sugar content will drop rapidly. At this time, the secretion of _ _ _ _ by the pancreas is obviously increased, and the function of this hormone is _ _ _ _ _ _ _.

34. Body temperature mainly depends on the two physiological processes of heat production and heat dissipation to maintain dynamic balance. When the outside temperature is relatively low, it is mainly used for heat dissipation, and the human body is mainly used for heat dissipation in high temperature environment.

35. What happened to each circuit shown in the figure below?

A picture:

Figure b:.

36. As shown in the figure, mark the symbol of voltmeter or ammeter in each circle of the circuit, and mark the positive and negative poles.

37. Compare the two experiments as shown in the figure, close the switch and heat the metal wire and glass column at the end of the old light bulb with alcohol lamp respectively (there are two metal wires embedded in it without touching each other), and the observed phenomenon is:

(1) The pointer of the ammeter in Figure A becomes smaller, indicating:

(2) The brightness of the small light bulb in Figure B will be (fill in "dim", "bright" or "unchanged").

Three. Analysis and calculation problems (5 points for each small question, *** 15 points)

38. The following is a physical diagram of the circuit for measuring the resistance of a small light bulb.

(1) Before the experiment starts, the switch should be _ _ _ _; Sliding vane of sliding rheostat should be moved to _ _ _ _ end.

(2) According to the instructions of the electric meter, calculate the resistance value of the small bulb.

39. A person with a mass of 60 kg walks on the road, and the contact area between each foot and the ground is 196 cm 2. What is the pressure on the road when pedestrians walk?

40. Please try to increase the solute mass fraction of 200g 10% salt solution to 20%.

Method:

Calculation process:

In 2005, Wenzhou City tested the academic level of the eighth grade of the new curriculum in the first semester.

Reference answers to scientific papers (1)

First, multiple-choice questions (2 points for each small question, ***50 points)

1C 2C 3A 4D 5C 6D 7C 8B 9D 10C 1 1B 12B 13B

14C 15C 16D 17C 18B 19D 20D 2 1B 22A 23C 24C 25B

2. Short answer questions: (65438+ 0 points per grid, ***35 points)

26, (1) evaporation; (2) Water vapor transport

27、( 1)5,95; Weighing; Dissolve (2) Turn the reagent bottle cork upside down and use coarse salt (just write 1).

28、0.98,0.98

29, (1)60 grams; (2) At 20℃, the solubility of A and B is equal, and the solubility of A changes obviously with temperature (other reasonable answers are given).

30.( 1) Coal, oil, natural gas and other energy consumption is large; A large reduction of forests; (2) Planting trees, using new energy sources, and improving the utilization rate of coal, oil, natural gas and other energy sources (just write 1, and give points for other reasonable answers)

3 1, (1) low rainy weather; (2) Warmth and rising

32, advanced, control

33, (1) B, diabetes; (3) insulin, reducing blood sugar content

34, skin sweat evaporation

35, open circuit, short circuit

36. (As shown on the right)

37, (1) metal resistance increases with temperature; darken

Three. Analysis and calculation problems (5 points for each small question, *** 15 points)

38、

(1) off, b (or right, d)

(2) Solution: R = = = 5.3Ω

A: Omit.

Note: For each grid 1 min, the reading of the electric meter is correct 1 min, and the calculation process and results are correct 1 min.

39. Solution: F=G=mg=60kg×9.8N/kg=588 cattle.

p= = =3× 104Pa

A: Omit.

Note: 2 points for correct pressure calculation, 2 points for correct area calculation 1 minute and 2 points for pressure calculation.

40. Solute solution: 200g×10%+x = (200g+x )× 20% x = 25g A: omitted.

or

Evaporative solvent decomposition: 200g×10% = (200g-y )× 20% y =100g a: omitted.

Description: Naming method 1, vertical correction 2, calculation correction 2.