(5分)维生素C(简称Vc，又名抗坏血酸)，易溶于水，易被氧化。人体缺乏Vc可能引发多种疾病。水果和蔬菜中含有丰富的Vc。某研究性学习小组对它探究如
下列条件下，两种气体的分子数一定不相等的是 ( ) A．相同质量、不同密度的N2和C2H4 B．相同体积、相同密度的CO和C2H4 C．相同温度、
According to a recent study out of the University of Pennsylvania's Wharton School, men with shaved heads are considered to be more manly, powerful, and successful than those with longer hair or th
N2H4是一种高效清洁的火箭燃料。0.25 mol N2H4(g)完全燃烧生成氮气和气态水时，放出133.5 kJ热量。则下列热化学方程中正确的是 A．1/2 N2H4(g)+ 1/2 O2(g)＝ 1/2 N
The expression “down to earth” means being open and honest. It is easy to get on with some one who is down to earth. A down-to-earth person is the opposite of someone who acts important or proud.
下列实验可以证明白磷(P4)和红磷互为同素异形体的是( )A.相同质量的白磷和红磷在足量氧气中充分燃烧，得到了相同质量的P2O5B.二者在一定条件下
微软公司将其开发的互联网浏览软件与视窗软件捆绑，高价销售。由于视窗软件在个人电脑操作软件市场上的高占有率，这种捆绑销售的做法使得其他
下列各组中的性质比较，正确的是A. 酸性HClO4>HBrO4>HIO4 B. 碱性NaOH>Mg(OH)2>Ca(OH)2C. 稳定性：HI>H2S> HCl D.氧化性：Na+>Mg2+>Al3+
