A:氢氧化钡溶液和稀硫酸反应:Ba2+ + SO42-=BaSO4↓
B:铁与稀硫酸反应: 2Fe + 6H+ =2Fe3+ + 3H2↑
C:稀醋酸加入到氢氧化钡溶液中:H+ + OH-=H2O
D:氯化铝溶液中加入过量氨水:Al3+ + 3NH3·H2O=Al(OH)3↓+ 3 NH4+
取5.0克氧化镁与氧化铜的混合物,加入稀盐酸(含0.2mol的HCl),恰好完全反应生成盐和水,原混合物中金属元素的质量是( )
— ______ people travel every year?
— Perhaps when we are talking about it, more than 100 planes have taken off around the world.