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
<u>Answer:</u> The final volume of the reaction is 4.69 L
<u>Explanation:</u>
The relationship of number of moles and volume at constant temperature and pressure was given by Avogadro's law. This law states that volume is directly proportional to number of moles at constant temperature and pressure.
The equation used to calculate number of moles is given by:
where,
are the initial volume and number of moles
are the final volume and number of moles
We are given:
Putting values in above equation, we get:
Hence, the final volume of the reaction is 4.69 L
Using the periodic table, the pair of non metals that has the most similar properties would be :
Oxygen and Selenium
at the periodic table, these both located on the same period
hope this helps
Answer: Kb = 3.15 × 10 ⁻⁴
Explanation:
This is how you calculate Kb for this reaction.
1) Equilibrium equation:
CH₃NH₂ + H₂O ⇄ CH₃NH₃⁺ + OH⁻
2) Kb = [CH₃NH₃⁺] [OH⁻] / [CH₃NH₂] ↔ all the spieces in equilibrium
3) From the stoichiometry [CH₃NH₃⁺] = [OH⁻]
Then, Kb = [OH⁻] [OH⁻] / [CH₃NH₂] = [OH⁻]² / [CH₃NH₂]
4) You get [OH⁻] from the pH in this way:
pOH + pOH = 14 ⇒ pOH = 14 - pH = 14 - 11.40 = 2.60
pOH = - log [OH⁻] = 2.60 ⇒ [OH⁻] = 10^(-2.6) = 0.002512
5) [CH₃NH₂] in equilibrium is given: 0.0200M
6) Now compute:
Kb = (0.002512)² / 0.0200 = 3.15 × 10 ⁻⁴
Answer:
No.
Explanation: You cannot change the formulas of individual substances because the chemical formula for a given substance is characteristic of that substance.
