【判断题】黄铜是铜和锌的合金,它的颜色随含锌量的增加会由黄红色变成淡黄色。( )
【单选题】--- It’s already ten. We’re going to miss the train! --- ______. It leaves in about an hour. We’ve got plenty of time.
【简答题】黄铜是铜和锌的合金。为了测定某黄铜样品中铜的质量分数,取20g该黄铜样品加入一定量稀硫酸中(Zn+H 2 SO 4 ==ZnSO 4 +H 2 ↑),恰好完全反应,产生氢气0.2g。求: (1)该黄铜样品中锌的质量。 (2)该黄铜样品中铜的质量分数(精确到0.1﹪)。
【单选题】--- It’s already ten. We’re going to miss the train!--- ______. It leaves in about an hour. We’ve got plenty of time.
【判断题】黄铜是铜和锌的合金,它的颜色随含锌量的增加由黄红色变成淡黄色。 ()
【简答题】--- It’s already ten. We’re going to miss the
train! --- ______. It leaves in about an hour. We’ve got plenty of time.A. Hurry up B. Relax C. Go on D. Be quick
【简答题】黄铜是铜和锌的合金.为了测定某黄铜样品中铜的质量分数,取20g该黄铜样品加入一定量稀硫酸中(Zn+H 2 SO 4 =ZnSO 4 +H 2 ↑),恰好完全反应,产生氢气0.2g. 求: (1)该黄铜样品中锌的质量. (2)该黄铜样品中铜的质量分数(精确到0.1%).