题目

长期存放的Na2SO3可能部分被氧化。某化学兴趣小组为了测定某无 水Na2SO3被氧化的程度，进行如下实验： (1) 甲同学设计如下实验流程：         ①甲同学选择的试剂a可以是________(填序号）。 A．盐酸酸化后的氯化钡  B.硝酸酸化后的氯化钡  C.氢氧化钡 ②判断试剂a是否过量的方法是__________________ ③操作II名称是________________________ ④Na2SO3的质量分数的表达式为__________________ (2)乙同学准确称量Na2SO3样品mg,并设计如下图所示的实验装置，进行相关实验： �6．Volunteers NeededAre you good with children？We need two people to volunteer your time at Sunny Children's Hospital．You need to be good with children．Your job is to play fun games with children．       If you can spare an hour three times a week，come and join us!Tel：605-968-5957Are you interested in repairing？       We have set up a group，Home Love，to help older people who need to fix up their homes．       If you have skills in repairing and you'd like to help the old，join us and spend eight hours a month．Tel：602-752-3425Email：HomeLove@hotmial．comClean beaches!       We need people who are strong and can help clean up Blue Water Beach．We don't want to put off this job till summer．We need help to collect and carry rubbish．       If you are free for two hours this weekend，come and join us!Tel：601-200-4365E-mail：BlueBeach@yahoo．comTeach English!       We need 5 volunteers to work as English teachers in S．O．S Children's Village this winter holiday．You need to be good at English，and open-minded with a loving heart．       If you can spare one week this winter holiday，join us!Tel：604-368-2745E-mail：Volneeded@hotmail．com41．You are good with children，so you can call atA．A．605-968-5957     B．602-752-3425      C．601-200-4365  D．604-368-274542．If you are interested in repairing things，you can go toB．A．Blue Water Beach                             B．Home LoveC．Sunny Children's Hospital                D．S．O．S Children's Village43．If you want to volunteer on the beach this weekend，it will take youB．A． one hour            B．two hours         C．eight hours       D．ten hours44．What can you do in S．O．S Children's Village？DA．Clean up the beach．B．Fix up old things．C．Play fun games．D．Teach English．