某合金(仅含铜、铁)中铜和铁的物质的量之和为y mol,其中Cu的物质的量分数为

题型:选择题

问题:

某合金(仅含铜、铁)中铜和铁的物质的量之和为y mol,其中Cu的物质的量分数为a,将其全部投入50 mL b mo1·L-1的硝酸溶液中,加热使其充分反应(假设NO是唯一的还原产物)。下列说法正确的是[ ]

A.若金属有剩余,在溶液中再滴入硫酸后,金属不会再溶解

B.若金属全部溶解,则溶液中一定含有Fe3+

C.若金属全部溶解,且产生336 mL气体(标准状况),则b=0.3

D.当溶液中金属离子只有Fe3+、Cu2+,则ab的关系为:b≥80 y (1-a/3)

考点:金属、非金属的有关计算
题型:选择题

精密称取供试品约0.5g,加冰醋酸与醋酐各10ml,加结晶紫指示液1~2滴,用高氯酸滴定液(0.1mol/L)滴定。用此方法测定含量的药物是()。

A.磺胺嘧啶

B.硫酸阿托品

C.盐酸麻黄碱

D.丙酸睾酮

E.罗红霉素

题型:选择题

社会主义荣辱观的主要内容是()

A.“八荣八耻”

B.中国特色社会主义共同理想

C.以改革创新为核心的时代精神

D.以爱国主义为核心的民族精神

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The telephone rang in my ninth-grade high school classroom.“Jill , please come to the counseling office (教导处)!”As I walked down the hall ,I  36  , why would someone want me to come to the counseling office? As I stepped into the counseling office ,I was   37  by a girl who needed to speak to someone about her friend. I was reassured by the school counselor (辅导员) that I was not   38  and that someone needed to talk with me. I was called because I was a member of   39 .

The Breakfast Club is   40  a club where one eats breakfast . It is an organization of   41  started thirteen years ago   42  a young student’ s suicide (自杀). His mother thought that it could have been prevented   43  her son talked to someone about how he was feeling.

The B. C. as we call it   44  ,give us an opportunity to   45  talk to our peers (同辈) about anything on their minds and   46  .Our   47  :We care but we don’t cure. Members from the previous year ,teachers ,and counselors   48  students for the Breakfast Club. The club is a   49  group including ,Asians ,blacks, whites, ,athletes, musicians, and students with all levels of   50  achievement ,The criteria (条件) for   51  the group is to be a good   52  ,be able to brainstorm ideas, and   53  give advice! We barely knew one another in the beginning , but we became  54  after all the training   55  we went through.

36. A. knew               B. wondered      C. murmured        D. shouted

37. A. met                B. hit            C. greeted           D. seated

38. A. in need             B. in difficulty     C. in trouble         D. in time

39. A. the counseling office  B. the school      C. our class          D. the Breakfast Club

40. A. just                B. only          C. such              D. not

41. A. teachers            B. students       C. blacks and whites   D. parents

42. A. as a result of        B.against         C. because           D. regardless of

43. A. if                 B. for            C. had              D. did

44. A. at present          B. in brief         C. for fun          D. for short

45. A. privately           B. secretly        C. frankly           D. kindly

46. A. in their family      B. in their hearts    C. in their school      D. from their friends

47. A. belief             B. banner          C. note             D. motto

48. A. select             B. permit          C. recognize         D. thank

49. A. perfect            B. international     C. diverse           D. morning

50. A. working           B. various         C. different          D. academic

51. A. going to          B. belonging to     C. contacting        D. participating

52. A. organizer          B. student         C. listener           D. speaker

53. A. quickly            B. then           C. not               D. yet

54. A. fast friends         B. common friends  C. strong opponents   D. dear relatives

55. A. study             B. care           C.struggle          D. experiences

题型:选择题

X线牙片上牙齿邻面颈部所呈现的三角形透明区是()

A.邻面龋

B.正常牙颈部

C.牙槽嵴吸收

D.牙颈部脱钙

E.投照角度不正确所致

题型:选择题

如何调整中心轴间隙?

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