Science
Relative atomic masses that may be used in this paper: H-1 C-12 O-16 F-19 Ca -40
Take 10 N/kg for g in the calculations in this paper.
I. Multiple Choice Questions (There are 20 questions in this question, each of which carries 3 marks, ***60 marks. Please select the question in a consistent with the meaning of the option, do not choose, multiple choice, wrong choice are not given points)
1. the following are common phenomena in daily life, which belongs to the chemical change is
A. Sucrose dissolves in water B. Iron rusts C. Ice melts D. Balloon inflatable becomes larger
2. the following are not differentiated from the stem and leaves of the plant is
A. black pine B. B. fern C. soybean D. kelp
3. One of the plans of China's lunar exploration project is to launch a lunar rover to the Moon to further explore the basic profile of the Moon. The following description of the Moon is correct
A．The Moon can not shine during the day, but can shine at night．B．The surface of the Moon is bright and dark, and the bright area is called the lunar sea
C．Early in the formation of the Moon, the surface of the Moon can be formed into craters by the collision of small celestial bodies
D．The Moon's surface, in addition to the rocks and their debris, there is also air, but no water
4．The following belong to the phenomenon of linear propagation of light
5. A. Copper wire is used to make wires B. Carbon dioxide is used as a fire extinguisher
C. Natural gas is used as a fuel D. Dilute sulfuric acid is used to make hydrogen
6. The following experiments or investigations use the control of variables method
A. When measuring the temperature of a liquid, the temperature of the liquid is measured by the temperature gauge. When measuring the temperature of a liquid, the glass bulb of the thermometer should be in full contact with the liquid to be measured
B. When observing the epithelial cells of the human oral cavity with a microscope, the field of view should be brightened by the light before the observation
C. When investigating the incidence of influenza in relation to the seasons, the incidence of men and women should be counted separately
D. When investigating the relationship between the resistance of a conductor and the thickness of the conductor, the material of the conductor should be kept constant, such as length and temperature, Length and temperature, etc.
7. Sturgeon is a large, long life of a freshwater fish (as shown), the development and utilization of great value. At present, people have mastered the sturgeon artificial eggs and hatching technology, some parts of the city has vigorously develop the sturgeon aquaculture industry, has achieved significant economic benefits. The following description is correct
A. Sturgeon reproduction is in vitro fertilization, in vitro development B. Sturgeon large, belonging to the body fertilization of placenta
C. Long life is the cause of the genetic material continues to mutate D. Sturgeon artificial egg and hatching technology belongs to the cloning technology
8. The following and crustal movement and plate theory related to the narrative, is correct
9.
A. The world consists of seven plates B. The plates that make up the Earth collide and split apart
C. Volcanic eruptions are not a form of crustal movement D. When an earthquake occurs, you should quickly run to a larger room
9. When Xiaoming stood on a start-up escalator that was moving at a constant rate of speed and ascended from the first floor to the second floor, the following statements are correct<
A. Xiaoming is stationary relative to the ground B. Xiaoming's kinetic energy remains constant
C. Xiaoming's total mechanical energy remains constant D. The escalator converts mechanical energy into electrical energy
10. Hand, foot, and mouth disease is a common infectious disease caused by a variety of intestinal viruses, most of the patients are infants and young children under the age of 5 years old, the patient's symptoms of the appearance of herpes (as illustrated in the figure below) on the hands, feet, and the oral cavity. The patient's symptom is the appearance of herpes on the hands, feet and mouth (as shown in the figure).
A. The measures to isolate the patient belong to cut off the means of transmission
B. The human skin can block the invasion of pathogens belonging to the specific immunity
C. The enterovirus that can cause infants and young children to suffer from hand, foot and mouth disease belongs to the pathogens
D. The disinfection of the patient's used items belongs to the protection of the vulnerable The following is a correct understanding of Xiaoming's study of motion and forces
A. If two forces are equal in magnitude and direction, they must have the same effect
B. A lead ball pushed out of the air continues to fly in the air because it is subjected to inertia
C. A bottle of water that is stationary on a horizontal desk must have the same effect
D. A bottle of water that is stationary on a horizontal desk must have the same effect as the one that is used by a patient. C. Horizontal desks on the bottle must be balanced by the role of force
D. If the movement of the object is not subject to external forces, it will slowly come to a stop
12. The city is rich in water, biological and mineral resources, the following about the city's development and utilization of resources in the following accounts are correct
A. water resources are plentiful, there is no need to implement water-saving measures can be liberalized
D. limestone resources are abundant, the city's development and utilizationThe city has a lot of water resources.
D. Limestone resources are abundant, but should be developed in moderation to prevent the increase of environmental pollution
C. More species of wild animals, and the meat is delicious, conducive to the development of specialty catering
D. Large forest reserves, can be cut down for the production of disposable chopsticks, to improve the economic income of farmers
13. The following diagrams are correct
14.
14. rice - duck - ping **** is an emerging agricultural model, in which the aquatic plant red ping (commonly known as Manjiang red) suitable for survival in a shady environment, can be used as feed for ducks, ducks can eat harmful insects, duck manure fertilizer to promote the growth of rice. The following description is correct
A. redbud, rice and other plants crumbled in the producer B. all of the harmful insects in the rice paddy belongs to a population
C. harmful insects belong to the decomposer of the farmland ecosystem D. all of the redbud in the rice paddy and the ducks *** with the same composition of a biotope
15. shown in the figure for the solubility of the a, b two substances curves, the following The relevant statement is wrong
A. a, b solubility are increased with the increase in temperature
B. t1 ℃, b solubility is greater than the solubility of a
C. t2 ℃, a, b solubility are the same, are 40 grams
D. t3 ℃, a saturated solution of solute in the mass fraction of 60%
16．Recently, after a series of food safety incidents exposed in the media, everyone is asking "What can we still eat?" . The following accounts of food hygiene and balanced diet, the correct is
A. Detected meat containing "lean meat extract", processed into ham and sausage can be eaten
B. Contaminated fresh vegetables must be pickled before eating, but also reduce the incidence of cancer
C. China's food hygiene in general is safe
C. The food hygiene is generally safe. C. China's food hygiene is generally safe, every day should adhere to a reasonable combination of various types of food
D. To ensure that residents have balanced nutrition is the premise that food must be safe, and therefore as few types of food as possible for the better
17. Each kidney is composed of about one million renal units, such as the figure for the structure of a renal unit schematic diagram.
A. The inflow of arterial blood contains more carbon dioxide
B. The outflow of venous blood contains less carbon dioxide and metabolic wastes
C. The inflow of arterial blood and the outflow of venous blood contain less oxygen
D. The diagram shows that the glomerular filtration and tubular reabsorption are included
18.
18. Xiaoming read the table below and summarized some conclusions, which are correct
Density of some substances at 0℃ and 1 standard atmospheric pressure (kg/m3)
Water 1.0×103 Ice 0.9×103
Mercury 13.6×103 Dried pine 0.4×103
Alcohol 0.8×103 Copper 0.9×103
Density of some substances at 0℃ and 1 standard atmospheric pressure (kg/m3)
Water 1.0×103 Ice 0.9×103
Acohol 0.8×103 Copper 0.8×103 8.9×103
Kerosene 0.8×103 Aluminum 2.7×103
A. The densities of different substances must be different B. Solid substances must be denser than liquid substances
C. The densities of the same substances must be the same D. Solid copper and aluminum blocks of the same mass, the volume of the copper block is smaller
19. The four diagrams of the devices shown in the figure and their instructions for use are incorrect. The four devices shown in the figure and its use of instructions, the wrong one is
20. To ensure the safety of drivers and passengers, the car is equipped with a seat belt is not fastened prompt system. When the passenger sits on the seat, the seat under the switch S1 closed, if not wearing a seat belt, then the switch S2 disconnect, the indicator on the dashboard lights up; if the seat belt, then the switch S2 closed, the indicator is off. The following design of the most reasonable circuit diagram is
Two, short answer questions (this question has 9 questions 20 blanks, 2 points per blank, **** 40 points. Where you need to fill in the blanks are "▲" mark)
21. April 20, 2011, China Yiwu Cultural Products Trade Fair in Quzhou exhibition area to display the yellow wax stone, yellow wax stone texture comparable to jadeite jade, has a very high appreciation and collection value of yellow wax stone is the main component of silicon dioxide. Silicon dioxide (SiO2) belongs to ▲ (fill in "monomers" or "compounds"), silicon dioxide in the silicon element of the valence of ▲ price.
22. China's Long March series of carrier rockets successfully completed a number of launch tasks. Rocket in the acceleration process, fuel combustion chemical energy into ▲ energy, thus increasing the mechanical energy of the rocket; rocket use backward airflow and make their own force forward, which is the use of the role of force is ▲ principle.
23. As shown in the figure for the reaction of hydrogen and copper oxide experimental setup. Please analyze and answer:
(1) at the beginning of the experiment, the reasonable order of operation is ▲ (optional "A" or "B");
A. first heating, and then through the hydrogen B. first through the hydrogen, and then heated
(2) the phenomenon seen during the experiment is black. The phenomenon seen during the experiment is that the black copper oxide turns into a red substance, while water droplets appear at the mouth of the test tube, indicating that hydrogen gas has ▲ nature.
24. May 22, 2011, underwater archaeology to crack the "Nan'ao Ⅰ" mystery work in the South China Sea in full swing. Please analyze and answer:
(1) when the diver jumped into the sea water, due to the lower temperature of the sea water, the diver's skin blood vessels will ▲ (fill in the "contraction" or "diastole"), the skin blood flow is reduced, the heat dissipation is also reduced, is conducive to maintaining a stable body temperature;
24. stability;
(2) in the diver completely submerged in water and continue to dive in the process, the pressure of the sea water on the diver will ▲ (fill in the "bigger", "smaller" or "unchanged"), the diver's pressure will be ▲ (fill in the "bigger", "smaller" or "unchanged "), and the buoyant force on the diver will be ▲ (select "greater", "smaller" or "unchanged").
25. Hangzhou-Changsha high-speed rail Ngazhou section is under intensive construction, high-speed rail with ballastless track, that is, the roadbed without gravel, rails laid directly on the reinforced concrete roadbed (as shown in Figure A), the construction of the cost is high, but to ensure that the train fast-passing safety; traditional railroad rails laid on the sleepers, under the ballast of a small gravel pavement (as shown in Figure B). Please analyze and answer:
(1) the traditional railroad rails laid on sleepers, through the ▲ method to reduce the pressure, to prevent the rails from sinking;
(2) high-speed train into the station speed to be a little larger than the ordinary train, in order to avoid waiting for the passengers to be "sucked" to the train accidents, the platform safety lines The distance from the train should be greater (shown in Figure C). This is because the high-speed train into the station when the air flow velocity near the car body is more
large, air pressure is more ▲ (fill in "big" or "small").
26. The city has a large area of selenium-rich soil resources, planted in this soil, white lotus, sweet potatoes, rice, etc., due to the rich selenium is known as selenium-enriched products, exported to Europe and the United States market. Selenium-enriched products in the "selenium" refers to ▲ (fill in the "element", "molecule" or "atom"), it is known that It is known that selenium in the original nuclear charge of 34, the relative atomic mass of 79, the nucleus of a selenium atom consists of 34 protons and 45 ▲ composition.
27. Sulfurous iron ore (mainly FeS2) is the raw material of industrial sulfuric acid (H2SO4), the first step in the high temperature of sulfurous iron ore powder and oxygen to fully react to generate iron oxide and sulfur dioxide, and then after a series of transformation to generate sulfuric acid. The first step of the reaction can be expressed by the chemical equation:
4FeS2 + xO2 == 2Fe2O3 + ySO2 (x, y represents the number of stoichiometry), then where x = ▲ .
28. Xiao Li students did the following experiment: in a, b two. A, B, two beakers of the same size, each adding equal amounts of blue ink and red ink, the celery petiole from the base along the middle of the cut, respectively, inserted into the two beakers, as shown in the figure. After some time he found that the leaf on the left side showed blue color and the leaf on the right side showed red color. Please analyze and answer:
(1) In Y will be cut across the petiole, observed that there are many red dots on the cross-section, these red dots appeared in the part is the location of the conduit, indicating that the role of the conduit is ▲ ;
(2) If the petiole will be cut across the petiole in X, the phenomenon of cross-section seen on the surface of the ▲ (fill in an optional);
A. the left side of the blue points more than the red point is small, the right side of red point is more less blue dots
B. the circle around the blue dots, red dots in the center
C. blue dots and red dots mixed, evenly distributed
D. blue dots on the left side, red dots on the right side
(3) Xiaoli students continue the following experiment: in A, B two beakers with an equal amount of red ink, will be placed in the same place of the temperature of the two beakers, but only in the beaker B insert fresh celery. After a period of time, the liquid level falls faster is ▲ beaker, the beaker liquid level falls faster is mainly due to ▲ .
29. As shown in the figure for the fishing rod fishing diagram, O for the fulcrum, F1 that the hand on the fishing rod force, please complete the following questions:
(1) in the figure draw the fishing line on the fishing rod tension F2 arm l2;
(2) fishing rod belongs to the ▲ leverage (fill in the "labor-saving", "costly", "labor-saving", "labor-saving", "labor-saving", "labor-saving", "labor-saving", "labor-saving" and "labor-saving"). ", "laborious" or "equal arm").
Three, experimental investigation questions (this question has 5 questions 15 empty, 2 points per empty, ****30 points. Where to fill in the blanks are marked with "▲")
30. Xiaohua students are ready to use clarified lime water and sodium carbonate solution in the laboratory to produce sodium hydroxide solid. Please analyze and answer:
(1) the principle of the reaction: expressed by the chemical equation Ca (OH) 2 + Na2CO3 = CaCO3 ↓ + 2NaOH, the reaction belongs to the ▲ reaction (fill in the "chemical synthesis", "decomposition, "replacement" or "complex decomposition");
(2) experimental steps: take a certain mass of sodium carbonate solution added to the test tube, and then use the burette to the test tube drop by drop of clarified lime water, until just no longer produces a precipitate until, after the reaction The mixture obtained after the reaction is filtered, ▲ to get sodium hydroxide solid. In the process of filtration, a glass rod is used, the role of the glass rod is ▲.
31. It is a common scientific research method to convert quantities that are not easy to measure directly into perceptible and measurable quantities. Please analyze and answer:
(1) in the "study of the factors affecting the size of friction" in the experiment (shown in Figure A), with a spring dynamometer to pull the block, you must let the block in the horizontal plane to do ▲ movement, through the spring dynamometer on the number of signals can be known to the magnitude of friction;
(2) in the "study of the kinetic energy of an object" in the experiment (shown in Figure A), with a spring dynamometer to pull the block, must let the block in the horizontal plane do ▲ motion, through the spring dynamometer can be known to the size of friction;
(2) in the "Study the kinetic energy of the object and which factors are related" in the experiment (shown in Figure B), will be different mass of small steel ball from the same slope, the same height from rest to roll down the slope, by comparing the same wooden block is small steel ball pushed ▲, you can determine the size of the kinetic energy of the small steel ball just rolled to the horizontal plane.
32. An interest group of students to explore different concentrations of growth hormone to promote the rooting of plant cuttings, the experimental materials for the growth of the same poplar branches, divided into an equal number of six groups inserted into different concentrations of growth hormone solution and water culture. The experiment was completed in four times and in the same laboratory, each experiment until the branches no longer rooted, calculate the average number of roots produced by each group of branches; the results are shown in the table below. Please analyze and answer:
2×10-1g/L 2×10-2g/L 2×10-3g/L 2×10-4g/L 2×10-5g/L fresh water
May 26th 0 0 0 0 1 6 0
May 31st 0 0 0 0 2 11 0
June 5th 0 1 2 5 13 1
June 10th 0 2 5 6 16 1
(1)The purpose of setting up the clear water group in this experiment is ▲;
(2)The data in the table shows that the branches rooted the most when they were incubated with growth hormone at the concentration of ▲;
(3)It can be seen from the analysis that when the concentration of growth hormone is too large, the roots of the branches will not be produced. "unfavorable") rooting of branches;
(4) After analyzing the data in the above table, a student came to the conclusion that "the lower the concentration of growth hormone, the more obvious the effect of promoting rooting", do you think this conclusion is correct? The reason is ▲.
33. Xiaohua students to do the experiment of iron wire burning in oxygen, used two different methods to ignite the wire, carried out the following experiments. Please analyze and answer:
(1) put the wire on the flame of the alcohol lamp heating, when the wire red, the wire is moved to a sufficient amount of oxygen and a small amount of water in the cylinder, the wire can not be burned (shown in Figure A), this is because of the red wire to the cylinder, ▲ ;
(2) switch to a match to ignite the iron wire, the iron wire is in the sufficient amount of oxygen and a small amount of water in the cylinder The wire burned violently, sparks shot out, and produced a black solid (as shown in Figure B). Write the chemical formula of this black solid ▲ .
34. The French scientist Albert Feuer and the German scientist Pieter Bertrand. Fell and the German scientist Peter Greenberger, who were responsible for the discovery of giant magnetism. Greenberger won the Nobel Prize in Physics for their discovery of the giant magnetoresistance (GMR) effect. Xiaoming designed the circuit shown in the figure to study the relationship between the magnitude of GMR and the presence or absence of a magnetic field. Please analyze and answer:
(1) Disconnect S1, close S2, move the slide of the sliding rheostat R2, measured four sets of data of the two meters as shown in the table below. It can be seen that the resistance of GMR in the absence of magnetic field is ▲ ohm;
Experiment No. 1 2 3 4
U/volt 1.00 1.25 2.00 2.50
I/amp 2×10-3 2.5×10-3 4×10-3 5×10-3
And then close S1 and S2, keep the position of the wind slide unchanged, and move the slide of the rheostat R2
S1 and S2, keep the position of the wind slide unchanged, move the slide of the rheostat R2
S1 and S2 closed, and keep the position of the rheostat R2 unchanged. rheostat R2
slider, measured four sets of data of the two meters as shown in the table below, can be calculated when there is a magnetic field
GMR resistance size;
Experiment No. 1 2 3 4
U / volts 0.45 0.91 1.50 1.79
I / amps 0.3×10-3 0.6×10-3 1×10-3 1.2×10-3
(2) The conclusion drawn from the above experiment is ▲ ;
(3) Using the circuit designed by Xiaoming and keeping the original equipment unchanged, you can further study the problem related to the size of the giant magnetic resistance is ▲ .
Four, analysis and calculation questions (this question has four subtopics, the 35th 6 points, the 36th 9 points, the 37th 7 points, the 38th 8 points, ****30 points)
35. March 11, 2011, Japan, a magnitude 9.0 earthquake, the earthquake triggered a tsunami. Affected by this, the Fukushima Daiichi nuclear power plant explosion, a number of reactor units on fire. March 19, a Chinese company donated a 62-meter-long arm length pump to Japan, the pump is mainly involved in the nuclear power plant reactor water injection cooling work. Please complete the following questions:
(1) The pump was shipped from Changsha, and after 25 hours and 1,200 kilometers of long-distance transportation to Shanghai, it was then shipped to Japan. What is the average speed of transportation of this pump truck from Changsha to Shanghai?
(2) This pump truck injected 180 tons of water into the nuclear reactor unit in 1 hour, assuming that the height of injection is 50 m, how much work does the pump truck need to do on this water?
36. March 10, 2011, the city of a chemical enterprise occurred in the hydrofluoric acid leakage, after the firefighters on-site treatment, the leakage was controlled. Hydrofluoric acid is an aqueous solution of hydrogen fluoride (HF) gas, acidic, and highly toxic and corrosive, when a small amount of hydrofluoric acid leakage, a mixture of sand and dry slaked lime can be used to deal with. The chemical properties of hydrofluoric acid are similar to those of hydrochloric acid, and can be neutralized with slaked lime [Ca(OH)2] to produce calcium fluoride (CaF2) and water. Please analyze and answer according to the above information:
(1)The pH of hydrofluoric acid ▲ 7(select ">", "=" or "<");
(2) Highly toxic and corrosive are ▲ properties of hydrofluoric acid;
(3) How many kilograms of slaked lime are needed to react completely with 4 kilograms of hydrofluoric acid solution with a solute mass fraction of 35%?
37. a brand "first generation of hot air hand dryer" high thermal power, not only energy consumption, and the work of the internal temperature of the appliance is high, the electronics and wiring is easy to deteriorate, the use of short life; the current development of the "second generation of high-speed hand dryer" with a High-speed motor, wind speed can reach 100 meters / second, only a few seconds to dry hands, do not need high temperature, low thermal power, so low energy consumption, low failure rate, long service life.
Comparison table of the parameters of the first-generation hot air hand dryer and the second-generation high-speed hand dryer
Rated voltage Rated total power Hand drying time
The first-generation hot air hand dryer 220 volts 2000 watts 36 seconds
The second-generation high-speed hand dryer 220 volts 1100 watts 6 seconds
Please complete the following questions:
(1) With the (1)Compared with the "first generation hot air hand dryer", "the second generation of high-speed hand dryer" can speed up the drying of hands, the main reason is ▲ ;
(2)The second generation of high-speed hand dryer normal operation of the current is how much?
(3) If the price of electricity is 1 yuan / kWh, the normal use of a second-generation high-speed hand dryer compared with the use of a first-generation hot-air hand dryer, how much money can be saved a month? (are used 240 times a day, a month to 30 days)
38. In order to understand the growth pattern of the tea tree, a scientific research institution selected Wuniu early, Zhennong 117 and Longjing 43 three kinds of potted tea trees have grown a year of photosynthesis research, the experiments in the carbon dioxide concentration to maintain a constant, suitable moisture in the same greenhouse, and with scientific instruments measured three tea trees Varieties of organic matter accumulation per unit leaf area, the results of the experiment shown in Figure A, while recording the temperature in the greenhouse, shown in Figure B. Please analyze and answer:
(1) from Figure A can be seen, three varieties of tea tree unit leaf area in the peak of the amount of organic matter accumulated in the ▲ (fill in the specific time), indicating that at this time the plant's ▲ role is the strongest, the manufacture of the largest amount of organic matter;
(2) comprehensively analyze the experimental data of the Figure A and Figure B, you think that the experiment's conclusions are ▲ ;
(3) moderate drinking of tea It is good for health because tea contains a substance called catechin, which has the effect of lowering blood lipids and inhibiting atherosclerosis. It is known that the chemical formula of a catechin is C15H14O6, and the mass ratio of carbon and hydrogen elements in the catechin is C∶H= ▲.
Zhejiang Province 2011 Junior High School Graduates Academic Examination Paper (Quzhou Volume)
Science Test Questions Reference Answers
I. Multiple Choice Questions (There are 20 questions in this question, each question carries 3 points, ****60 points. Please choose one correct option in each question that meets the meaning of the question.)
Question No. 1 2 3 4 5 6 7 8 9 10
Answer B D C A A D A B B C
Question No. 11 12 13 14 15 16 17 18 19 20
Answer C B D A D C D D D D A B
Two, short-answer questions (There are 20 blanks in 9 subquestions in this question, and each blank is worth 2 marks, ****40 marks)
21. compound +4 22. within (or heat) each other 23.(1) B (2) reduction
24.(1) contraction (2) become larger unchanged 25.(1) increase the area of force (2) small 26. element neutron
27. 11 28.(1) transport of water and inorganic salts (2) D (3) B transpiration of the leaf blade
29.(1) (see right figure shows) (2) laborious
Three, experimental investigation questions (this question has 5 sub-questions 15 blanks, 2 points per blank, *** 30 points)
30. (1) complex decomposition (2) evaporation crystallization drainage 31. (1) uniformly linear (2) the size of the distance of the movement (or the movement of the distance)
32. (1) to act as a control (2)2 × 10-5g / L (3) unfavorable (4) incorrect because no experiments have been carried out with lower concentrations of growth hormone
33.(1) The temperature of the wire falls below the ignition point (2) Fe3O4
34.(1) 500 (2) The resistance of the giant magnetic resistor becomes significantly larger in the presence of a magnetic field
(3) To study the relationship between the magnitude of the giant magnetic resistor and the strength of the magnetic field (or to study the magnitude of the giant magnetic resistor and the direction of the magnetic field)
35.(2) To study the relationship between the magnitude of the giant magnetic resistor and the direction of the magnetic field
36.(3) To study the relationship between the magnitude of the giant magnetic resistor and the strength of the magnetic field
37. The relationship between the magnitude of the resistance and the direction of the magnetic field)
Four, analysis and calculation of the genus (this question has four sub-topics, the 35th question 6 points, the 36th question 9 points, the 37th question 7 points, the 38th question 8 points, *** 30 points)
35. (6 points)
Solution: (1) v = S / t = 1200 km / 25 hours = 48 km / hour
(2) G=mg =180,000 kg x 10 N/kg = 1.8 x 106 N
W=Fs=Gh = 1.8 x 106 N x 50 m = 9 x 107 J
Answer: (1) The average speed of transporting this pumper from Changsha to Shanghai is 48 km/h
(2) This pumper needs to do work of 9 x 107 J on this water
p> 36.(9 marks)
(1)< (2)Chemistry (3)Solution: let X kg of slaked lime be required
2HF + Ca(OH)2 = CaF2 + 2H2O
40 74
4 kg x 35% X kg
40:74 = 4 kg x 35%:X kg
X = 2.59
A: 2.59 kg of quicklime is required.
37.(7 marks).
Solution, (1) the speed of air flow on the surface of the liquid is large (or the wind speed is large) (2) I = P / U = 1100 watts / 220 volts = 5 amps
(3) The first generation of hot-air hand dryer: W = Pt = 2 kilowatts × 36 / 3,600 hours × 240 = 4.8 kilowatt-hours
The second generation of high-speed hand dryer; W = Pt = 1.1 kilowatts × 6 / 3600 hours × 240 = 0.44 kWh
(4.8 kWh - 0.44 kWh) × 1 yuan / kWh × 30 = $130.8 yuan
A: (2) The current of the second-generation high-speed hand dryer is 5 amps when it is working normally
(3) It can save $130.8 yuan in a month 38.(8 points) (1) 10:00 Photosynthesis
(2)Photosynthesis in tea trees increases with temperature, and is strongest up to 35°C, after which photosynthesis gradually decreases with increasing temperature
(3)90:7