Answer:
Explanation:
exothermic reactions are the reactions which involve the release of energy.
the energy released can be of any forms ,for example heat,light .
all the combustion reactions are exothermic reactions
Answer: There are 4.8 x 1024 hydrogen atoms in 2.0 moles of CH4
Answer:
oxygen is an element because it is a pure substance which cannot be split into simpler substances by chemical means
The awnser is central canal the third one