一个玻璃瓶的质量是0.2kg，玻璃瓶装满水时的总质量是0.7kg，装满另一种液体时的总质量是0.6kg，那么这种液体的密度是多少？ρ_水=1.0×10³ kg/m³．

阅读短文，判断正误。

    Mr. Black has a bigfarm. There is a vegetable garden on the farm. You can see carrots, green beans, potatoes and tomatoes. On his farm, there are many animals, too. There are ducks, sheep, hens, horses and goats. Mr. Black likes his animals. He feels(感觉) happy. My friends and I often go to the farm and play with the animals. Some friends like horses and some like goats. I like sheep. We often help Mr. Black clean the farm.

四川遂宁境内的卓筒井是手工制盐的活化石，被誉为“中国古代第五大发明”、“世界石油钻井之父”，不仅是古代劳动人民勤劳、智慧的象征，也造福了千秋万代．其工艺流程如图1所示包括下面五个步骤：

请结合所学化学知识，回答下列问题：