某无色溶液中可能含有Na+、K+、Fe3+、NH4+、Cu2+、SO42-、SO

题型:多选题

问题:

某无色溶液中可能含有Na+、K+、Fe3+、NH4+、Cu2+、SO42-、SO32-、CO32-、Cl-、Br-这几种离子中的若干种,依次进行下列实验,观察到的现象记录如下:①pH试纸检验,溶液的pH>7.②取少量原溶液,向溶液中加入过量的BaCl2和盐酸的混合溶液,无白色沉淀生成.③另取少量原溶液,向溶液中滴加足量氯水,无气体产生,再加入CCl4振荡,静置后CCl4层呈橙色,用分液漏斗分液.④向分液后的水溶液中加入Ba(NO32溶液和HNO3溶液,有白色沉淀产生,过滤.⑤在滤液中加入AgNO3和HNO3的混合溶液有白色沉淀产生.则关于原溶液的判断中不正确的是(  )

A.肯定存在的离子是Na+、K+、SO32-、Br-

B.肯定不存在的离子是Fe3+、Cu2+、NH4+、SO42-、CO32-

C.无法确定原溶液中是否存在Cl-

D.若步骤④改用BaCl2溶液和盐酸的混合溶液,则对溶液中离子的判断无影响

考点:离子共存离子的检验
题型:多选题

20℃,氯化钠的溶解度为36g,在此温度下,要提纯50g含有少量泥沙的粗盐,溶解粗盐加入水的体积最好约为(水的密度为1g/cm3)(  )

A.只要粗盐全部溶解,任意体积

B.189mL

C.139mL

D.18mL

题型:多选题

阅读理解。

     Skinner Creek ESL Guest Ranch offers a unique outdoor adventure camp for international students.

Students who come to Skinner Creek have the opportunity to learn English in an environment entirely

different from a regular school setting. English classes are designed to meet the academic and spoken

levels of each student. All English classes will be taught by instructors qualified in teaching English as a

second language. All levels of English are available.

     After class, students can enjoy many outdoor activities in a controlled and safe environment.

Experienced managers and camp teachers will prepare each activity to the level appropriate for each

student.

Students' safety is a priority (优先考虑的事) for the staff of Skinner Creek ESL Guest Ranch. Students

are monitored at all times and supervisors are in the cabins with the students at night. Staff members have

St. John's First Aid and Transportation and Wilderness First Aid. An emergency clinic is nearby and

accessible 24 hours.

     English Classes:

     Class hours are from Monday to Friday, 9:00 am-2:00 pm with a one-hour break for lunch.

     Students are challenged in reading, writing, grammar, vocabulary building and conversational English.

     Fun After-class Activities:

     Great after-class activities include: horseback riding lessons, hiking, baseball, volleyball, badminton,

mountain hiking, bonfires and much more.

     Time to watch videos and TV and play games.

     Experience Canadian family life.

     Weekends:

     Special all-day and overnight weekend activities include: camping, days at the lake(fishing, swimming

and boating) and more.

     Travel Information:

     Students will be picked up at Vancouver airport and dropped off again for their individual flights.

Transportation to and from the ranch will be provided as well as overnight stays in Vancouver.

     Please contact the ranch directly for prices: skinnercreek@telus. net.

1. If you attend Skinner Creek Summer Camp, you will___.

A. sometimes have English Classes outdoors.

B. learn how to deal with dangers in the wild.

C. enjoy different sports activities after class

D. experience the traditional farmer lifestyle.

2. How many hours of English classes do students have every week in Skinner Creek?

A. 35 hours

B. 28 hours

C. 25 hours

D. 20 hours

3. How will most students travel to Skinner Creek if they want to attend the camp?

A. By air

B. By car

C. By boat

D. By train

题型:多选题

下述关于喉癌常规放疗描述正确的是()。

A.声门癌放疗首选60Co或4MV直线加速器

B.喉癌通常采用分段照射以减少上呼吸道和上消化道并发症

C.放疗分次剂量宜低于2Gy,即1.8Gy/次

D.第二原发肿瘤是放疗常见的急性期反应

E.声门上型喉癌的射线能量选择对疗效影响较大

题型:多选题

清心定惊

题型:多选题

国家监督管理机关调查食品安全事故,应当坚持实事求是、尊重科学的原则,及时、准确查清事故性质和原因,认定事故责任,提出()。

A.警告

B.追究责任

C.行政处罚

D.整改措施

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