kim loại thiếc có nhiệt độ nóng chảy là 232 độ C, thiếc hàn nóng chảy ở khoảng 180 độ C. cho bt thiếc hàn là chất tinh khiết hay có trộn lẫn chất khác nhau? giải thik

the molecules move in straight line until they collide with each other or with the walls of the container. collisions are perfectly elastic; when two molecules collide, they change their directions and kinetic energies, but the total kinetic energy is conserved.

explanation:

one negative thing it that it can kill water animals. another negative thing is it can cause the destruction of ecosystem. one way water pollution can be reduced is to conserve energy.