北海虽赊扶摇可接

1.把带火星木条放入未装满氢气的集气瓶中,现象怎样?会有"砰"的一声吗?那放人装满氢气的集气瓶中呢?2.如果在氯酸钾制氧气实验中,发现将带火星木条放入制取的氧气中,无论上下底部带火星 氯气和氢氧化钙的化学方程式!感激不尽感激不尽! 一个圆柱形水池,直径是20米,深2米.在池内的侧面和池底抹一层水泥,水泥面的面积是多少平方米? 化学速率的理解问题化学高手请进1.化学反应速率为什么要定义成单位时间浓度的改变而不是单位时间物质的量的改变？我认为一个反应中反应物的物质的量一定改变，但浓度却有可能不变 H2O2中的O元素 是氧化性还是还原性还是氧化性和还原性都有 X,Y,Z三种主族元素位于周期表中连续的三个不同周期,原子顺序Z>X>Y,其中Y原子的次外层电子数为2,X原子的次外层电子数与Y,Z原子的次外层电子数均不同,X+Y的族序数之和=Z的族序数.已知X的氢氧 0.8吨化成分数是多少吨 0、8%化成分数 请大家帮我几个英语选择题,Taiwan police cannot decide whether to treat it as an extremely clever act of stealing or an even cleverer cheat (诈骗). Either way , it could be the perfect crime (犯罪), because the criminals are birds—hor The policeman has questioned all the people ---------- the robbery.A.relating to B.related to C.connected with---------on the earth that the stars have changed their positions.A.It appears to the scientists B.The scientists appears to beC.It looks to The Olympic champions ( ) all the audience excited at the 2008 Olympic Games.A.let B.saw C.made D.felt 英语的两道选择题,大家帮帮忙吧My father is_____a book in his room A.looking B.seeing C.reading DwatchingHIs uncle lokks_____a policeman. A.with B.on Cat D.like 已知等差数列an的通项公式为an=4n-3,求它的前n项和s 已知数列{an}的通项公式为an=4n-3,证明这个数列是等差数列 一个圆柱形水池的直径是8米.深是5米.这个水池的占地面积是多少平方米?在水池内部抹一层水泥.抹水泥的的面积是多少平方分米? 已知知数列{an},{bn},均为等差数列,前n项和分别为Sn,Tn,若Sn/Tn=2n+2/n+3,则a10/b10=__ 乘法口诀表中那俩句口诀只能计算一道乘法试题 一弹性球从100米高处自由落下,每次着地后又跳回原来高度的一半再落下,第10次着地时所经过的路程和为__米 动点A从原点出发向数轴负方向运动,同时,动点B也从原点出发向数轴正方向运动,3秒后,两点相距15个单位长度．已知动点A、B的速度比是1：4．（速度单位：单位长度/秒）（1）求出两个动点运 一平行四边形底6.5分米高是3.4分米每平方米重0.75千克钢板重多少千克 2的2000次方是多少 2的2000次方是多少啊 2个2000次方等于多少? 1.My English teacher isn't______.She's_______.(我的答案是C）A.a Chinese;English B.an English;JapaneseC.English;an Japanese D.an English;a Chinese2.Can you borrow some money______ me?I want to buy some books.A.to B.from C.for D.of (我的答案 1、What ____ you doing?----- I was reading a story about Lucy.A.did B.was C.were D.do2、There are many children playing in the park,Some are riding bikes,some are flying kites ,_____ are reading under the trees.3、My brother likes watching TV.I of 彩票一张二元每次买递增二元78次总计多少元?如2+2=4+2=6+2=8 设数列{an}的前n项积为Tn,Tn=1-an,设cn=1/Tn（1）证明数列{Cn}是等差数列（2）求数列{an}的通项公式（3）是否存在正整数m,n（1＜m＜n）,使得a1,am,an成等比数列?若存在,求出所有的m,n的值,若不存在, 在正整数数列中 前n项和Sn满足Sn=1/8*(an+2)^2求证是等差数列,若Cn=1/（an*an+1）,求Cn的前n项和Tn. 记数列An前n项积为Tn=1-An,记Cn=1/Tn.（1）证明Cn是等比数列；（2）求An如题确实是等差,我打错字了%>_ 1.-I tried to make Jim_____his plan,but I found it impossible.-Well ,I saw you ______that when I went past.A.change,do B.changes,doing C.to change,do D.change,doing2.It's 9:00 again.It's time to have your temperature______.A.to take B.taking C.taken 二元一次方程求解x+y=86x+4y=38 X+Y=5,2X+Y=8 .4X+3Y=5,X-2Y=4 .这2题用带如消元法解7X-2Y=3,9X+2Y=-19 用加减消元法解