3 Mg + 1 Fe2O3 →2 Fe + 3MgO
Type of Reaction: Single displacement.
Answer:
a) 381.2 g
b) 39916 g
c) 0.0013 lb mol
d) 29.6 g mol
Explanation:
The molecular weight (mw) of a compound is the mass of it per mole, so it's the ratio of the mass (m) per mole (n).
a) The molecular weight of one mol is found at the periodic table. So, for Mg, mw = 24.3 g/mol, for Cl = 35.5 g/mol, so for MgCl2, mw = 24.3 + 2*35.5 = 95.3 g/mol. The g mol is the mass divided by the molecular weight:
g mol = m/mw
4 = m/95.3
m = 381.2 g
b) The pound (lb) is a unity of mass, and the lb mol is a unity of the mass divided by the molecular weight. So, by the periodic table, the molecular weight of C3H8 is 3*12 (of C) + 8*1 (of H) = 44 lb/mol.
lb mol = m/mw
2 = m/44
m = 88 lb
1 lb = 453.592 g
So, m = 88*453.592 = 39916 g
c) The molecular weight of N2 is 2*14 (of N) = 28 lb/mol.
m = 16/453.592 = 0.0353 lb
lb mol = m/mw
lb mol = 0.0353/28
lb mol = 0.0013 lb mol
d) The molecular weight is 2*12 (of C) + 6*1(of H) + 1*16(of O) = 46 g/mol
3 lb = 1360.78 g
g mol = m/mw
g mol = 1360.78/46
g mol = 29.6 g mol
The concentration of a solution is the number of moles of solute per fixed volume of solution.
Concentration (C) = number of moles of solute (n) / volume of the solution (v)
we have to find the volume of the solution when 36.0 g of Ca(OH)₂ is added to water to make a solution of concentration 0.530 M
mass of Ca(OH)₂ added - 36.0 g
number of moles of Ca(OH)₂ - 36.0 g / 74.1 g/mol = 0.486 mol
we know the concentration of the solution prepared and the number of moles of Ca(OH)₂ added, substituting these values in the above equation, we can find the volume of the solution
C = n/v
0.530 mol/L = 0.486 mol / V
V = 0.917 L
answer is 0.917 L
Answer:
See explanation
Explanation:
The number of electrons in each principal energy shell increases as the number of shells increases because more electronic orbitals become available to accommodate the electrons.
For instance, the n= 2 level only accommodates eight electrons in the s and p orbitals whereas the n=3 level accommodates 18 electrons in s, p and d orbitals respectively.
Each principal level accommodates 2n^2 electrons where n= the principal energy shell.
