用向下排气法在容积为V mL的集气瓶中收集氨气，由于空气尚未排净，最后瓶内气体的平均式量为19，将此盛满气体的集气瓶倒置于水中，瓶内水马上升到一定高度后，即停止上升，则在同温同压下，瓶内剩余气体的体积为（ ）
A．
mLV 4
B．
mLV 5
C．
mLV 6
D．无法判断
设最后瓶内气体中氨气的物质的量为x，空气的物质的量为y，
由瓶内气体的平均式量为19，则
=19，解得17x+29g x+y
=5，x y
气体的体积之比等于物质的量之比，
即VmL的集气瓶中收集氨气为
VmL，5 6
将此盛满气体的集气瓶倒置于水中，水上升的体积为氨气的体积，剩余气体为空气，
瓶内剩余气体的体积为VmL-
VmL=5 6
mL，V 6
故选C．
| The basic story is very old indeed and familiar to most of us. The heroine, Cinderella, is treated cruelly by her stepmother and mocked by her two ugly stepsisters. And even though her father loves her, she can’t tell him how unhappy she is because her stepmother has bewitched him. One day Cinderella’s stepmother and stepsisters are invited to a ball at the royal palace. Cinderella is told she cannot go and is understandably very unhappy. However, her fairy godmother comes to the rescue and, waving her magic wand, produces some beautiful clothes for Cinderella as well as a carriage to convey her to the ball. There, she dances with the handsome prince, who falls in love with her… Just a sweet, pretty tale Not in the view of Ellen Macintosh, who has written extensively about fairy tales. "This story features the stock, two-dimensional characters of most fairy tales, and little character development is attempted," she says. Indeed, although her comment does make one wonder why simplicity of this sort should be out of place in a story for children. Be that as it may, Ellen’s main problem is with what the story implies. "Instead of standing up to her cruel stepmother and absurd stepsisters, Cinderella just waits for a fairy godmother to appear and solve her problem. But wouldn’t you want a daughter of yours to show more spirit " The story is enduring, whatever its shortcomings, and it doesn’t take much in the way of analytical skills to see its influence on a number of recent Hollywood productions, all aimed at girls aged five to fifteen. In these versions for the silver screen, the Cinderella character no longer has to clean the house and has no siblings to make her life a misery, though she persists in not showing much backbone. The character of the rich and handsome stranger, however, is retained, and in some cases really is a prince. The role of the fairy godmother is often played by coincidence or sheer luck; we live in an enlightened age when even very young children might reject the notion of fairies. The wicked stepmother may be transformed into a villain of some sort. In the majority of film versions, the heroine has a profession and is even permitted to continue working after marrying her prince — this is the twenty — first century, after all. Doesn’t the success of these films indicate that the story has relevance to children even today "Yes," admits Ellen, who sees its message as being rooted in a fundamental childhood desire for love and attention. "Most children experience a sense of inner loneliness as they are growing up and empathies with the protagonist who faces some sort of test or challenge. This can be seen in the original story of Cinderella, where the fairy godmother tells the heroine that she must learn to be gracious and confident if she is to go to the ball. She has to grow spiritually, and by maturing, she becomes attractive to the prince, thus ensuring that the ending of the story will be happy." "In the later versions, this element is missing," says Ellen, "and the theme of the story is simply that a girl’s role in life is to be more beautiful than other little girls so that she can carry off the prize: the handsome prince. Is this really what we want girls to grow up believing " |
In Ellen’s view, what makes the Cinderella story so appealing
A．(A) Children can identify with the heroine.
B．(B) Little girls enjoy being challenged.
C．(C) It has an element of magic.
D．(D) Cinderella is more beautiful than other girls.