题目内容
根据课文内容和重点短语填空
A.Metals are widely used in the world.It’s hard to ________ ________ a world without metals.If we want to use metals well, I think it’s necessary for us to know how exactly they ________ ________ different substances, for example, water.From the table we know, ________, ________ and ________ can react with cold water.And ________, ________ and ________ can react with steam.But iron only has reaction with water and steam, ________ has no reaction with them at all.
B.Let’s do an experiment aiming to find out if there’s a change in weight when copper burns in air.Use the following apparatus to do an experiment.Write down the method.
copper, Bunsen burner, a balance, a crucible
First, put the copper in the ________.Then put the ________ on the ________ and weigh it.Next heat the copper.Light the ________ and hold the ________ over it.Finally, weigh the copper again.
Result:It weighs a lot heavier than before.
Conclusion:There is a change in weight when copper burns in air.
解析:
A.think of react with potassium sodium calcium magnesium aluminum zink partial copper B.crucible crucible balance Bunsen burner crucible |