Answer:
Explanation:
One of the properties of a liquid is that, <u>it's particles move freely (not tightly packed)</u> hence the reason for <u>it's free flowing (no definite shape)</u> when shaken in a container, unlike a solid whose <u>particles are tightly packed with restricted/no movement</u> and hence the reason for it's compactness and it's definite shape.
When a plastic solid (whose particle is tightly packed and have a restricted movement/no movement) is placed near a heat source, <u>it's particles gains energy in the process and starts to move (though slightly free) and become less tightly packed</u> hence the reason it is observed that plastic solids near a heat source melts.
From the above, it can be deduced that a liquid and a plastic solid near a heat source <u>have there particles move freely (and not tightly packed) hence making the two substances flow freely with no definite shape.</u>
Substances have different tendencies to donate or accept electrons. When a really good donor meets a great acceptor, the chemical reaction releases a lot of energy. Oxygen (O2) is the best electron acceptor and is used in many aerobic reactions (reactions with oxygen). Hydrogen gas (H2) is a good electron donor.
When O2 and H2 are combined, along with a catalyst, water (H2O) is formed. This example of a redox reaction can be written like this:

Oxidation reaction is used in redox reaction
