χημική ουσία 用英语:

Magnesium is a chemical element.

Immediately after it caught fire, the chemical factory blew up.

Our company is planning to build a new chemical plant in Russia.

The chemical formula for water is H₂O.

Chemical companies are waiting until everything dies down before reinvesting.

The chemical symbol H expresses hydrogen.

It is only recently that crude oil has come to be used to make chemical products.

Chemical products account for approximately two-thirds of our exports.

As a result of some factories using fossil fuels, chemical emissions have already caused serious environmental problems.

Professor Morita presided at a meeting of the Chemical Society.

The scientist found that rats treated with the chemical lost on average 30% of their weight.

You'd better be careful with this liquid - I wouldn't trust a chemical substance. It can eat away your skin.

They work to prevent harm not only to workers but also to property, the environment, and the public by inspecting workplaces for chemical, radiological, and biological hazards

Some of the chemicals used to kill insects on farms can be bad for our health.

You must wear gloves when handling any of these chemicals.