Answer:
C. Chemical change
Explanation:
A physical change is where something is changed but it doesnt affect the build up of the chemical. For example, if you broke sticks and threw them on the ground, that would be a physical change because the change is happening to the physical being of the object and not its chemical buildup. However, if you lit those sticks on fire, that would be considered a chemical change because you end up with two substances, ash and the remnants of the stick. A nuclear reaction would result in something blowing up so its not that. And a physical property is like what it looks like or how it smells. Hope I helped you!
Answer is: theoretical molarity of water is 55.1222 mol/L.<span>
d(H</span>₂O) = 0.9922 g/mL.
M(H₂O) = 2 · Ar(H) + Ar(O) · g/mol.
M(H₂O) = 2 + 16 · g/mol = 18 g/mol.
c(H₂O) = d(H₂O) ÷ M(H₂O).
c(H₂O) = 0.9922 g/mL ÷ 18 g/mol.
c(H₂O) = 0.0551 mol/mL.
c(H₂O) = 0.0551 mol/mL · 1000 mL/L = 55.1222 mol/L.
Hydrogen is usually –1. This is INCORRECT. The oxidation number for H is +1.
Oxygen is usually –2. This is CORRECT.
A pure group 1 element is +1. This is INCORRECT. It does not follow. This will depend on the other elements and the overall charge.
A monatomic ion is 0. This is INCORRECT. Diatomic ion is 0.
69.9%
Explanation:
To find the mass percentage of iron in the compound in Fe₂O₃, we would go ahead to express the given molar mass of the iron to that of the compound.
Mass percentage = 
x 100
Molar mass of Fe = 55.85g/mol
Molar mass of O = 16g/mol
Molar mass of Fe₂O₃ = 2(55.85) + 3(16) = 159.7g/mol
Mass percentage = 
= 69.94% = 69.9%
learn more:
Mass percentage brainly.com/question/8170905
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5 Valence electrons .......... Hope it helps, Have a nice day:)
