问题 问答题

解热镇痛阿斯匹林的有效成分是乙酰水杨酸().为测定某解热镇痛药阿斯

匹林产品的纯度,称取样品0.25g,准确加入0.10mol/LNaOH溶液50mL,煮沸60min,发生如下反应:

冷却后用0.10mol/LHCl溶液返滴过量的NaOH,消耗该HCl溶液25.00mL.

(1)计算0.25g阿斯匹林样品反应消耗的NaOH的物质的量(除乙酰水杨酸外,其他物质不与NaOH反应).______

(2)计算该产品中乙酰水杨酸的含量(乙酰水杨酸的摩尔质量是180g/mol).______.

答案

n(HCl)=0.025L×0.1mol/L=0.0025mol,n(NaOH)=0.05L×0.1mol/L=0.005mol,

(1)与反应的氢氧化钠的物质的量为0.005mol-0.0025mol=0.0025mol,

故答案为:0.0025mol;

(2)n(NaOH)=n(HCl)+3n(),则m()=0.0025mol×

1
3
×180g/mol=0.15g,

该产品中乙酰水杨酸的含量为

0.15g
0.25g
×100%=60%,

故答案为:60%.

单项选择题

An Indian anthropologist, Chandra Thapar, made a study of foreign cultures, which had customs similar to (91) of his native land. One culture in (92) fascinated him because it reveres one animal (93) sacred, much as the people in India (94) the cow. The things he discovered might interest you (95) you will be studying India as part of this course.
The tribe Dr. Thapar (96) is called the Asu and is found on the American continent north of the Tamhumara of Mexico. Though it seems to be a (97) developed society of its type, it has an overwhelming (98) with the care and feeding of the rac—an animal much like a bull in size, strength and temperament. In the Asu tribe, it is almost a social (99) to own at least one (100) not more rats. People not possessing at least one are (101) in low esteem by the community because they are too poor to (102) one of these beasts properly. Some members of the tribe, to (103) their wealth and social prestige, even own (104) of racs.
(105) the rac breed is not very healthy and usually does not live more than five to seven years. Each family invests large (106) of money each year to keep its rac healthy and shod, for it has a tendency to throw its shoes often. There are rac (107) in each community, perhaps more than one if the community is particularly (108) . These specialists, however, due to the long period of ritual training they must undergo and (109) the difficulty of obtaining the right selection of charms to treat the rac, demand (110) offerings whenever a family must treat an ailing rac.

A.although

B.since

C.as if

D.when

单项选择题 A1型题