Answer:
See the explanation and examples below, please.
Explanation:
To calculate the molar mass of a substance you must have the atomic weights of each component:
Example NaCl ionic compound (sodium chloride, known as table salt)
Molar mass NaCl = Atomic weight Na + Atomic weight Cl = 22, 98 gr + 35, 45gr = 58.35 grams / mol
Example covalent compound HCl (hydrochloric acid) = Atomic weight H + Atomic weight Cl = 1, 004gr + 35, 45 gr = 36, 45 grams / mol
In the case of having compound H20 (water), it is calculated:
Molar mass NaCl = 2 x (Atomic weight H) + Atomic weight 0 (the atomic weight of 1 mol of Hydrogen is multiplied by 2)
For this problem, we use the Hess' Law.
ΔHrxn = ∑(ν*Hf of products) - ∑(ν*Hf of reactants)
The ν represents the corresponding stoichiometric coefficients of the substances, while Hf is the heat of formation. For pure elements, Hf = 0.
Hf of Al₂O₃ = <span>−1676.4 kJ/mol
</span>Hf of Fe₂O₃ = <span>-826.0 kJ/mol
Thus,
</span>ΔHrxn = 1*−1676.4 kJ/mol + 1*-826.0 kJ/mol
<em>ΔHrxn = -2502.4 kJ/mol</em>
Answer:
9.15×10²³molecules
Explanation:
moles=number of particles/Avogadro's number
1.52=x/6.02×10²³
by cross multiplication;
x=1.52×6.02×10²³
=9.15×10²³
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9,000 meters
Because density is altered by altitude, the helium balloon can reach a height of 9,000 meters, or 29,537 feet. Anything higher than this altitude will cause the helium within the balloon to expand and the balloon to pop.
According to Clausius-Clayperon equation,
is the vapor pressure at boiling point = 760 torr
is the vapor pressure at T_{2} =638.43 torr
Temperature
Δ
Plugging in the values, we get
ln
Therefore, the boiling point of octane = 389 K - 273 = 
