The reaction for the formation of MgO(s):
2 Mg (s) + O2(g) -à
2MgO(s) ΔH = -601.24
kJ/mol
<span>The enthalpy
information is taken from: http://webbook.nist.gov/cgi/inchi?ID=C1309484&Mask=2</span>
From the equation and with an enthalpy change of -231 kJ:
-231 kJ * 2 mol Mg * (1/-601.24 kJ/mol) = 0.76841 mol Mg
Then, with the molar mass of MgO = 40.3,
0.76841 mol Mg *(2 mol MgO/2 mol Mg)* 40.3 g/mol MgO = <span>30.967 g MgO</span>
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The boiling point of the fluid depends on the intermolecular forces between the fluid atoms and molécules, as these forces must be disrupted to switch from a fluid to a gas. The stronger the intermolecular forces, the greater the point of boiling.
Answer:
Explanation:
At constant pressure and temperature, the mole ratio of the gases is equal to their volume ratio (a consequence of Avogadro's law).
Hence, the <em>complete combustion reaction</em> that has a ratio of 100 ml of gaseous hydrocarbon to 300 ml of oxygen, is that whose mole ratio is 1 mol hydrocarbon : 3 mol of oxygen.
Then, you must write the balanced chemical equations for the complete combustion of the four hydrocarbons in the list of choices, and conclude which has such mole ratio (1 mol hydrocarbon : 3 mol oxygen).
A complete combustion reaction of a hydrocarbon is the reaction with oxygen that produces CO₂ and H₂O, along with the release of heat and light.
<u>a. C₂H₄:</u>
- C₂H₄ (g) + 3O₂ (g) → 2CO₂(g) + 2H₂O (g)
Precisely, for this reaction the mole ratio is 1 mol C₂H₄: 2 mol O₂, hence, this is the right choice.
The following analysis just shows that the other options are not right.
<u>b. C₂H₂:</u>
- 2C₂H₂ (g) + 5O₂ (g) → 4CO₂(g) + 2H₂O (g)
The mole ratio for this reaction is 2 mol C₂H₂ :5 mol O₂.
<u>с. С₃Н₈</u>
- C₃H₈ (g) + 5O₂ (g) → 3CO₂(g) + 4H₂O (g)
The mole ratio is 1 mol C₃H₈ : 5 mol O₂
<u>d. C₂H₆</u>
- 2C₂H₆ (g) +7 O₂ (g) → 4CO₂(g) + 6H₂O (g)
The mole ratio is 2 mol C₂H₆ : 7 mol O₂
