A、液态溴蒸发成气态溴 B、SnO<sub>2sub>(s) + 2H<sub>2sub>(g) = Sn(s) + 2H<sub>2sub>O(l) C、电解水生成H<sub>2sub>和O<sub>2sub> D、公路上撤盐使冰融化
A、液态溴蒸发成气态溴 B、SnO<sub>2sub>(s) + 2H<sub>2sub>(g) = Sn(s) + 2H<sub>2sub>O(l) C、电解水生成H<sub>2sub>和O<sub>2sub> D、公路上撤盐使冰融化
A、液态O<sub>2sub> B、液态CO<sub>2sub> C、液态N<sub>2sub> D、P<sub>5sub>(OH)<sub>2sub>
A、K<sub>1sub>+K<sub>2sub> B、K<sub>1sub>-K<sub>2sub> C、K<sub>1sub>·K<sub>2sub> D、K<sub>1sub>/K<sub>2sub>
A、K<sub>1sub>+K<sub>2sub> B、K<sub>1sub>-K<sub>2sub> C、K<sub>1sub>·K<sub>2sub> D、K<sub>1sub>/K<sub>2sub>
A、在图示轮系中,各齿轮均为标准齿轮,已知z<sub>1sub>=20,z<sub>2sub>=48,z<sub>2’sub>=20。试求z<sub>3sub>及传动比i<sub>1Hsub>。 src="https://img.ppkao.com/2018-06/liuqianlan/2018061309131663418.jpg" />
A、已知298.2K时,NaCl(s)、H<sub>2sub>SO<sub>4sub>(l)、Na<sub>2sub>SO<sub>4sub> (s)和HC<sub>lsub>(g)的标准摩尔生成焓分别为-411、-811.3、-1383和-92.3 kJ·mol<sup>-1sup>,求下列反应的src="https://img.ppkao.com/2019-04/yuanhuijuan/2019041517091565373.jpg" />
2NaCl(s) + H<sub>2sub>SO<sub>4sub>(l) = Na<sub>2sub>SO<sub>4sub>(s) + 2HC<sub>lsub>(g) 
A、KMnO<sub>4sub>法测定H<sub>2sub>O<sub>2sub> B、溴酸盐法测定苯酚 C、间接碘量法测定Cu<sup>2+sup> D、用已知准确浓度的Na<sub>2sub>S<sub>2sub>O<sub>3sub>溶液标定I<sub>2sub>
A、Δ<sub>rsub>H<sup>θsup><sub>m1sub>-Δ<sub>rsub>H<sup>θsup><sub>m2sub> B、2Δ<sub>rsub>H<sup>θsup><sub>m1sub>+Δ<sub>rsub>H<sup>θsup><sub>m2sub> C、2Δ<sub>rsub>H<sup>θsup><sub>m1sub>—Δ<sub>rsub>H<sup>θsup><sub>m2sub> D、Δ<sub>rsub>H<sup>θsup><sub>m1sub>+ 2Δ<sub>rsub>H<sup>θsup><sub>m2sub>