Equal, for all practical purposes, due to conservation of mass. In theory, it can be slightly less, but the effect is insignificant. Do some reading on "mass deficit" for more information; but briefly, energy can escape during a chemical reaction, and this energy has some mass.
It can be either.
Either pair can be greater..
The algebraic sum of the charges in a compound is zero. Each atom contributes either a negative or a positive charge to form the compound when they react with each other.
Not always.
no because 3 + 0= 3 and three is not greater than itself
substance
If two elements are chemically combined, they become a compound which will have totally different chemical and physical characteristics than either of the two original elements.
It might be either a molecule or an ionic compound.
a compound
a compound. on their own they are either elements or molecularly smaller compounds.
That's a compound. The bonds can either be covalent, ionic... there are a range.
Compounds are formed in chemical reactions of either other compounds, or elements, or a combination of elements and compounds.For example burning hydrogen and oxygen is an exothermic chemical reaction that forms water, a new compound.
A pure substance made of two or more elements is a compound.
It's sodium chloride if you're talking about the compound NaCl. And no, the property of the compound will not be the same as the property of either of the elements.
The components of a pure substance can be either molecules or atoms.
It could be either. Solid, liquid, and gas are different phases of matter and both compounds and elements are matter and can be in any of those phases depending on temperature and pressure.
They are called the trans-uranic elements. They are either synthetic or the rare product of radioactive decay.