问题 问答题

某合作小组欲探究Al、Cu、Ag三种金属活动性,特设计如下实验:把一根洁净的铝丝浸入硫酸铜溶液中,过一会取出,观察铝丝表面的现象把一根洁净的铜丝浸入硝酸银溶液中,过一会取出,观察铜丝表面的现象

(1)请填写下列空白

实验现象反应的化学方程式
铝丝浸入硫酸铜溶液中______________________ 2Al+3CuSO4=Al2(SO43+3Cu
铜丝浸入硝酸银溶液中铜丝表面有银白色物质析出___________________________ 
(2)据此得出三种金属活动性由强到弱的顺序为______.

(3)该组同学发现,洁净的铝丝浸入硫酸铜溶液时,还观察到铝丝表面有气泡产生.你推断硫酸铜溶液pH______7.(填>、<、=)

答案

(1)铝丝浸入硫酸铜溶液中,置换出铜,

故答案为:铝丝表面有红色物质析出;

铜丝浸入硝酸银溶液中,由现象铜丝表面有银白色物质可知铜在溶液中置换出银,

故选Cu+8AgNO3=Cu(NO38+8Ag.

(8)由8Al+3CuSO═Al8(SO3+3Cu,Cu+8AgNO3=Cu(NO38+8Ag可知,金属的活泼性Al>Cu>Ag,

故选Al>Cu>Ag.

(3)洁净的铝丝浸入硫酸铜溶液时,还观察到铝丝表面有气泡产生,则说明硫酸铜溶液中有较多的H+,显酸性,

故答案为:<.

问答题
单项选择题

An official report, addressing concerns about the many implications of genetic testing, outlined policy guidelines and legislative recommendations intended to avoid involuntary and/or ineffective testing, and to protect confidentiality. The report identified urgent concerns, such as quality control measures (including federal oversight for testing laboratories) and better genetics training for medical practitioners. It recommended voluntary screening, urged couples in high-risk populations to consider carrier screening, and advised caution in using and interpreting pre-symptomatic or predictive tests, because certain information could easily be misused or misinterpreted.

About three in every 100 children are born with a severe disorder presumed to be genetic or partially genetic in origin. Genes, often in concert with environmental factors, are being linked to the causes of many common adult diseases such as heart disease, hypertension (high blood pressure), various cancers, Alzheimer’s disease, etc. Tests to determine predisposition to a variety of conditions are under study, and some are beginning to be applied.

The report recommended that all screening, including screening of newborns, be voluntary. Citing the results of two different voluntary newborn screening programs, the report said these programs can achieve compliance rates equal to or better than those of obligatory programs. State health departments could eventually require the offering of tests for diagnosing treatable conditions in newborns, however, careful pilot studies for conditions diagnosable at birth need to be done first.

Although the report asserted that it would prefer that all screening be voluntary, it did note that if a state requires newborn screening for a particular condition, the state should do so only if there is p evidence that a newborn would benefit from effective treatment at the earliest possible age. Newborn screening is the most common type of genetic screening today. More than four million newborns are tested annually so that effective treatment can be started in a few hundred infants.

Prenatal (preceding birth) testing can pose the most difficult issues. The ability to diagnose genetic disorders in the fetus(胎儿)far exceeds any ability to treat or cure them. Parents must be fully informed about risks and benefits of testing procedures, the nature and variability of the disorders they would disclose, and the options available if test results are positive.

Obtaining informed consent—a process that would include educating participants, not just processing documents—would enhance voluntary participation. When offered testing, parents should receive comprehensive counseling, which should be nondirective. Relevant medical advice, however, is recommended for treatable or preventable conditions.

Genetics also can predict whether certain diseases might develop later in life. For single-gene diseases, population screening should only be considered for treatable or preventable conditions of relatively high frequency. Children should be tested only for disorders for which effective treatments or preventive measures could be applied early in life.

The phrase " in concert with " (Line 2, Para. 2)maybe best replaced by()

A. in contrast with

B. on account of

C. with relation to

D. in company with