X=107 because the sides of a hexagon must add up to 720
A, B, C, and D, because they are changing from a solid to a liquid, liquid to solid, and solid to gas. Phase changes are when a solid, liquid, or gas, turns into a solid, liquid, or gas. Ex. Ice melting is a solid changing into a liquid. Hope this helps!
- The reaction in which we can't take back the product to reactant form .Or in simple words the reaction which is irreversible is called chemical reaction
Example:-
We cannot pull back the reaction to get wax back .
The subscript 2 in the formula o2 indicates that there are 2 atoms of the element oxygen, represented by the symbol "O." The subscript to the right of the symbol tells how many atoms are present of that element.