6. Which scientific law is best demonstrated by the reaction shown in the diagram? 2H2 + O2-2H20
Hydrogen Oxygen Water
ALA
law of universal gravitation
law of angular momentum
law of conservation of energy
law of conservation of mass

law of conservation of mass

Explanation:

According to the law of conservation of mass, mass is neither created nor destroyed.

This is actually the law that guides the balancing of chemical reaction equations.

On the left side we have four atoms of hydrogen and two atoms of oxygen. Exactly the same number of atoms of each element is seen on the right hand side in accordance with the law of conservation of mass.

the law of conservation of mass states that in a chemical reaction, the total mass of reactants is equal to the total mass of products. because atoms are only rearranged in a chemical reaction, there must be the same number of sodium atoms and chlorine atoms in both the reactants and products

1. for the first question, we must find the mass of the anhydrous salt, mgso₄. the molar mass for mgso₄·7h₂o is 246.47 g/mol, while that of mgso₄ is 120.37 g/mol.7.834 g mgso₄·7h₂o * 1 mol mgso₄·7h₂o/246.47 g * 1 mol mgso₄/1 mol mgso₄·7h₂o * 20.37 g mgso₄/mol = 0.647 g mgso₄

2. mass of water = mass of sample - mass of anhydrous salemass of water = 7.834 - 0.647 = 7.19 gpercent water in hydrate = 7.19/7.834 * 100 = 91.74%