Answer:
23.34 %.
Explanation:
- The percentage of water must be calculated as a mass percent.
- We need to find the mass of water, and the total mass in one mole of the compound. For that we need to use the atomic masses of each element and take in consideration the number of atoms of each element in the formula unit.
- <em>Atomic masses of the elements:</em>
Cd: 112.411 g/mol, N: 14.0067 g/mol, O: 15.999 g/mol, and H: 1.008 g/mol.
- <em>Mass of the formula unit:</em>
Cd(NO₃)₂•4H₂O
mass of the formula unit = (At. mass of Cd) + 2(At. mass of N) + 10(At. mass of O) + 8(At. mass of H) = (112.411 g/mol) + 2(14.0067 g/mol) + 10(15.999 g/mol) + 8(1.008 g/mol) = 308.5 g/mol.
- <em> Mass of water in the formula unit:</em>
<em>mass of water</em> = (4 × 2 × 1.008 g/mol) + (4 × 15.999 g/mol) = 72.0 g/mol.
- <em>So, the percent of water in the compound = [mass of water / mass of the formula unit] × 100 = [(72.0 g/mol)/(308.5 g/mol)] × 100 = 23.34 %</em>
I think it’s 44.6 J, but I’m not to sure so hoped this helped /:).
I think this question is talking about electrons (since they flow freely in the electron cloud of an atom).
a) 1 mole of Ne
b) i/2 mole of Mg
c) 1570 moles of Pb.
d) 2.18125*10^-13 moles of oxygen.
Explanation:
The number of moles calculated by Avogadro's number in 6.23*10^23 of Neon.
6.23*10^23= 1/ 6.23*10^23
= 1 mole
The number of moles calculated by Avogadro's number in 3.01*10^23 of Mg
3.2*10^23=1/6.23*10^23
= 1/2 moles of Pb.
Number of moles in 3.25*10^5 gm of lead.
atomic weight of Pb=
n=weight/atomic weight
= 3.25*10^5/ 207
= 1570 moles of Pb.
Number of moles 4.50 x 10-12 g O
number of moles= 4.50*10^-12/16
= 2.18125*10^-13 moles of oxygen.
Basis: 1 L of the substance.
(1.202 g/mL) x (1000 mL) = 1202 g
mass solute = (1202 g) x 0.2 = 240.2 g
mass solvent = 1202 g x 0.8 = 961.6 g
moles KI = (240.2 g) x (1 mole / 166 g) = 1.45 moles
moles water = (961.6 g) x (1 mole / 18 g) = 53.42 moles
1. Molality = moles solute / kg solvent
= 1.45 moles / 0.9616 kg = 1.5 m
2. Molarity = moles solute / L solution
= 1.45 moles / 1 L solution = 1.45 M
3. molar mass = mole solute / total moles
= 1.45 moles / (1.45 moles + 53.42 moles) = 0.0264
