Answer: (C) conservation of matter
Solution: Law of conservation of matter or mass states that' total mass of the reactants should always be equal to the total mass of the product that is the total mass is remained conserved in a chemical reaction.
A balanced chemical equation always follow this law.
For example:

Mass of hydrogen = 1 g/mol
Mass of Oxygen = 16 g/mol
Total mass on the reactants = 2(2×1)+(2×16)= 36g/mol
Total mass on the product side = 2[(2×1) +16] = 36 g/mol
As,
Mass on reactant side = Mass on the product side
Therefore, a balanced chemical reaction follows Law of Conservation of mass.
white phosphorus is used in flares and explosives, so may be important in warfare, etc. Red phosphorus is used in matches (side of matches) and in fertilizers which are essential to growing plants. I don't know if that is economically important, but there are many ways that phosphorus benifit the economy. One downside on the economy is that phosphorus is one of the main ingredients in meth, which of course causes trouble for the economy ( law enforcement, medical, etc. )
Answer:
The Aufbau Principle
Explanation:
In the ground state of an atom or ion, electrons fill atomic orbitals of the lowest available energy level before occupying higher-energy levels.
Q. How many molecules of H2O can be produced from reactants in container below?
A. 3 molecule of molecules H2O will be produced from reactants in container.
<em><u>Explanation</u><u>:</u></em>
There are seven molecules of H2 and three molecule of O2 are there in the container Q, 6 molecules of H2 will react with 3 molecules of O2 to produce 3 molecules of H2O. One molecule of Hydrogen will not take part in reaction and will be present in container Q after then reaction, and the mass in overall reaction is conserved!
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