Help me with homework.

Coefficient is the number that is Compound or element in the reaction For example : . Here 2 is the coefficient and it means that there are two SEPARATE INDIVIDUAL Hydrogen ions are present they are not bonded together.

Coefficient is the number which tells you how many number of molecules or atoms are present in a reaction. It is a whole number that is placed infront of the substance. If you change the coefficient it simply means you are decreasing or increasing the number of molecules. It is not the part of the chemical formula.

Subscript is the placed after the Element. Example , here 2 is the subscript after the preceding element i.e. Hydrogen.

The subscript is the number which tells you what is the amount of that element in the compound or simply how many number of atoms of that that element are present. It is the part of the chemical formula.

molecule has two atoms of hydrogen and it cant be changed.

Number of molecules

Yes, it is correct. You cannot change subscripts in a chemical formula to balance a chemical equation and you can change only the coefficients. Changing subscripts changes the ratios of atoms in the molecule and the resulting chemical properties, as it is a part of a chemical formula.

1- A big two before H is Coefficient

2- A small two after H is Subscript

Number of atoms = (Number of moles) x (Avogadro's Number i.e. )

If there is no coefficient present, it means that there is only One molecule or compound is present.

they are all solids.