| When water is broken down electrolytically into oxygen and hydrogen, the water molecules are broken down into oxygen atoms and hydrogen atoms. Every two oxygen atoms form an oxygen molecule, and every two hydrogen atoms form a hydrogen. molecule. A large number of oxygen molecules come together to become oxygen, and a large number of hydrogen molecules come together to form hydrogen gas. When water evaporates into water vapor, the distance between the water molecules and the water increases. the molecules themselves do not change, which is a physical change. So the answer is: when water is electrified and broken down into oxygen and hydrogen, it is a change in the water molecules, which is a chemical change; when water evaporates into water vapor, it is a change in the water molecules. distance between water molecules, which is a changephysically. |
Please explain the essential difference between the following changes from the point of view of molecules and atoms: decomposition of water by electricity and evaporation of water by heat
< p>Evaporation of water by heat, the principle is that water molecules continue to expand when heated, but water molecules do not decompose do not and do not produce new molecules, so it is a physical change.The principle of water electrification is that water molecules decompose into hydrogen atoms and oxygen atoms after being electrified, and then combine to produce water molecules. hydrogen and oxygen molecules, forming two new molecules, so it is a chemical change.
So the answer is: physics; chemistry ; there was no ; the electrical decomposition of water is a chemical change. The work carried out byelectrons overcome the attraction between oxygen and hydrogen atoms. atoms, producing water. The molecules become oxygen molecules and hydrogen molecules. The bond is broken and electrical energy is converted into chemical energy.
The evaporation of water when heated is a physical change. The increase in temperature intensifies the irregular thermal motion of water molecules enough to break away from the Van
der
De Waals force and hydrogen Due to bonding, the distance between water molecules becomes about ten times greater than the radius.