Density is mass divided by volume. Therefore, volume is mass divided by density.

The nucleus!! This is made up of protons and neutrons that each weigh about 1 amu.
Electrons are not found in the nucleus and weigh almost nothing so chemistry in school doesn’t bother with them :)
Answer:
Explanation:
Plantae Animalia Archaebacteria and Animalia Protista and Eubacteria . Protista and Eubacteria kingdom(s) include organisms that are autotrophic or heterotrophic
Answer:
2HClO4(aq) + Ca(OH)2(aq) → Ca(ClO4)2(aq) + 2H2O(l)
Perchloric acid + Calcium hydroxide → Calcium perchlorate + Water.
Explanation:
This is a neutralization reaction where the acid, Perchloric acid reacts completely with an appropriate amount of base, aqueous Calcium hydroxide to produce salt, aqueous Calcium perchlorate and water, liquid H2O only.
During this reaction, the hydrogen ion, H+, from the HClO4 is neutralized by the hydroxide ion, OH-, from the Ca(OH)2 to form the water molecule, H2O.
Thus, it is called a neutralization reaction.
Answer:
0.4694 moles of CrCl₃
Explanation:
The balanced equation is:
Cr₂O₃(s) + 3CCl₄(l) → 2CrCl₃(s) + 3COCl₂(aq)
The stoichiometry of the equation is how much moles of the substances must react to form the products, and it's represented by the coefficients of the balanced equation. So, 1 mol of Cr₂O₃ must react with 3 moles of CCl₄ to form 2 moles of CrCl₃ and 3 moles of COCl₂.
The stoichiometry calculus must be on a moles basis. The compounds of interest are Cr₂O₃ and CrCl₃. The molar masses of the elements are:
MCr = 52 g/mol
MCl = 35.5 g/mol
MO = 16 g/mol
So, the molar mass of the Cr₂O₃ is = 2x52 + 3x35.5 = 210.5 g/mol.
The number of moles is the mass divided by the molar mass, so:
n = 49.4/210.5 = 0.2347 mol of Cr₂O₃.
For the stoichiometry:
1 mol of Cr₂O₃ ------------------- 2 moles of CrCl₃
0.2347 mol of Cr₂O₃----------- x
By a simple direct three rule:
x = 0.4694 moles of CrCl₃