问题 选择题

已知NH3和HCl都能用来作喷泉实验。若在同温同压下用等体积烧瓶,一个收集满NH3,另一个收集满HCl气体,做喷泉实验,如图所示,喷泉实验停止后,两个烧瓶内溶液的关系是(不考虑溶质的扩散及静止时液面高度的影响)

A.溶质的物质的量浓度相同、溶质的质量分数不同

B.溶质的质量分数相同,溶质的物质的量浓度不同

C.溶质的物质的量浓度和溶质的质量分数都不同

D.溶质的物质的量浓度和溶质的质量分数都相同

答案

答案:A

题目分析:同温同压下用等体积烧瓶收集的NH3和HCl的物质的量相同,二者均易溶于水,所以溶液充满整个烧瓶,即所得溶液的体积相同,所以所得溶液中溶质的物质的量浓度相同;但等物质的量的NH3和HCl的质量不同,所以溶液中溶质的质量分数不同,答案选A。

多项选择题
阅读理解

Jockeys(职业赛马骑师) are the smallest athletes. They are rarely over five feet six, or 120 pounds. The lighter the weight on the horse, the faster it can go.

Riding fast horses on the track is tough on the small jockeys. The jockey doesn’t“sit”on the horse. He leans forward on his legs. The strain is on his thighs(大腿) and calf(小腿) muscles. As jockeys age, their legs“go”first. Jockeys also need arm strength. It’s a strain holding a 1000-pound racehorse.

On muddy days, jockeys get a pounding of mud. The mud comes flying off the hooves(蹄) of the horses in front. “It feels like someone is punching you all over,”says one rider.

And a jockey can be hurt. A jockey can have a leg jammed between two horses. Or it can get caught between horse and the rail. The worst accidents are from falls. A horse may fall on his rider. Or horses behind may trample if he hits the track. In one year about 240 riders are hurt badly. That’s one out of six jockeys.

But the jockeys are well-paid. A jockey keeps about ten percent of the money his horses win. Jacinto Vasquez, a five-foot-three comer, has ridden horses to $7,000,000 in wins in the last eight years, which means he does almost $100,000 a year.

Why do some jockeys do better than others? “It isn’t the way a boy sits on a horse or uses the reins or the whip,”says Conn McCreary. McCreary was a top jockey of the 1950’s. He rode two Kentucky Derby winners. “Most jockeys do this the same. It’s the ‘feel’ he has for the horses.”

“When you come right down to it, it just seems that horses run better for some riders,” McCreary says. “A real good jockey doesn’t lose with the best horse. And sometimes he’ll win with the second or third best.”

Many Latin-American riders, like Jacinto, seem to have the knack. “Maybe it’s because we grew up with horses,”says Jacinto. “Maybe it’s because we like to ride. There was a strike at Aqueduct last year. We, Jorge Velasquez, and Angel Cordero (two other top Latin riders) went to a park. We rented horses, and rode around the bridle path(骑马专用道)!”

小题1:The main idea of Paragraph 1 is about ______________.

A.the size of jockeys.

B.the age of jockeys

C.the size of the horse

D.the speed of the horse小题2:When a jockey is riding a fast horse, he doesn’t __________.

A.really sit on the horse

B.lean forward on his legs

C.use much arm strength

D.get any mud on wet track小题3: The most dangerous problem for a jockey arises __________________.

A.when his leg is jammed between two horses

B.when his clothes are splashed over with mud.

C.when the jockey’s horse falls on the jockey

D.when the jockey is not well paid小题4:A really good jockey can often win a race ____________.

A.only when he rides on the best horse

B.even when he rides the second best horse

C.when he rides on a rented horse

D.if the horse is just a Kentucky Herby小题5: The underlined word “Knack” in the last paragraph probably means__________________.

A.special skill

B.dangerous hobby

C.riding culture

D.excellent horses.