问题 选择题

下列叙述正确的是(  )

①CO2、NO2、P2O5均为酸性氧化物

②Ca(HCO32、Fe(OH)3、FeCl2均可由化合反应制得

③碘晶体分散到酒精中、氯化钠晶体分散到酒精中所形成的分散系分别为:溶液、胶体

④灼热的炭与CO2的反应、Ba(OH)2•8H2O与NH4Cl的反应均既属于氧化还原反应,又是吸热反应

⑤需要通电才可进行的有:电离、电解、电泳、电镀、电化腐蚀

⑥氯化铁溶液与氢氧化铁胶体具有的共同性质是:能透过滤纸,加热蒸干、灼烧后都有氧化铁生成

⑦按照纯净物、混合物、强弱电解质和非电解质顺序排列的是.单甘油酯、混甘油酯、苛性钾、次氯酸、氯气

⑧金属元素和非金属元素形成的化合物一定是离子化合物.

A.①②③④

B.②③⑥

C.①③④⑤⑥⑦⑧

D.②④⑦

答案

①NO2和碱反应生成硝酸钠、亚硝酸钠,发生了氧化还原反应,二氧化氮不是硝酸的酸酐,故①错误;

②CaCO3+CO2+H2O=Ca(HCO32、4Fe(OH)2+O2+2H2O=4Fe(OH)3、2FeCl3+Fe=3FeCl2均可由化合反应制得,故②正确;

③碘晶体分散到酒精中形成的分散系是溶液,氯化钠晶体分散到酒精中所形成的分散系是胶体,故③正确;

④Ba(OH)2•8H2O与NH4Cl的反应不属于氧化还原反应,故④错误;

⑤电解、电泳、电镀需通电,电离是溶液中水分子或熔融作用下进行;电化腐蚀是形成原电池反应发生的腐蚀;不需要通电,故⑤错误;

⑥溶液和胶体能通过滤纸,加热氯化铁溶液时,铁离子水解生成氢氧化铁,蒸干、灼烧时氢氧化铁分解生成氧化铁和水,氢氧化铁胶体加热时聚沉生成沉淀,蒸干、灼烧时氢氧化铁分解生成氧化铁和水,故C正确;

⑦氯气不是非电解质,电解质是化合物.故⑦错误;

⑧金属元素和非金属元素形成的化合物不一定是离子化合物,也可以形成共价化合物,如AlCl3是共价化合物,故⑧错误;

综上所述:②③⑥正确;

故选B.

单项选择题
单项选择题

The Frugal Gourmet Cooks American

by Jeff Smith

Our real American foods have come from our soil and have been used by many groups— those who already lived here and those who have come here to live. The Native Americans already had developed an interesting cuisine using the abundant foods that were so prevalent.

The influence that the English had upon our national eating habits is easy to see. They were a tough lot, those English, and they ate in a tough manner. They wiped theft mouths on the tablecloth, if there happened to be one, and they ate until you would expect them to burst. European travelers to this country in those days were most often shocked by American eating habits, which included too much fat and too much salt and too much liquor. Not much has changed! And, the Revolutionists refused to use the fork since it marked them as Europeans. The fork was not absolutely common on the American dinner table until about the time of the Civil War, the 1860s. Those English were a tough lot.

Other immigrant groups added their own touches to the preparation of our New World food products. The groups that came still have a special sense of self-identity through their ancestral heritage, but they see themselves as Americans. This special self-identity through your ancestors who came from other lands was supposed to disappear in this country. The term melting pot was first used in reference to America in the late 1700s, so this belief that we would all become the same has been with us for a long time. Thank goodness it has never worked. The various immigrant groups continue to add flavor to the pot, all right, but you can pick out the individual flavors easily.

The largest ancestry group in America is the English. There are more people in America who claim to have come from English blood than there are in England. But is their food English Thanks be to God, it is not! It is American. The second largest group is the Germans, then the Irish, the Afro-Americans, the French, the Italians, the Scottish, and the Polish. The Mexican and American Indian groups are all smaller than any of the above, though they were the original cooks in this country.

Immigrant groups, when they got settled down in the United States, still have had their own sense of self-identity because().

A. their foods are easily identified among all the foods Americans eat.

B. their foods stand out in sharp contrast to foods of other countries.

C. they know pretty well what elements of American food are of their own countries’ origin.

D. they know pretty well how their foods contribute to American cuisine.