How much heat is released when 75 g of octane is burned completely if the enthalpy of combustion is -5,500 kJ/mol CsH18? C8H18 +
1 answer:
Answer : The correct option is, (D) 3600 kJ
Explanation :
Mass of octane = 75 g
Molar mass of octane = 114.23 g/mole
Enthalpy of combustion = -5500 kJ/mol
First we have to calculate the moles of octane.
Now we have to calculate the heat released in the reaction.
As, 1 mole of octane released heat = -5500 kJ
So, 0.656 mole of octane released heat = 0.656 × (-5500 kJ)
= -3608 kJ
≈ -3600 kJ
Therefore, the heat released in the reaction is 3600 kJ
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First you calculate the pOH of the solution:
pH+ pOH = 14
3.25 + pOH = 14
pOH = 14 - 3.25
pOH = 10.75
<span>Concentration of [OH]</span>⁻<span> in solution:
</span>
[ OH⁻ ] =
[ OH⁻ ] = 10^ - 10.75
[OH⁻] = 1.778 x 10⁻¹¹ M
hope this helps !
pH+ pOH = 14
3.25 + pOH = 14
pOH = 14 - 3.25
pOH = 10.75
<span>Concentration of [OH]</span>⁻<span> in solution:
</span>
[ OH⁻ ] =
[ OH⁻ ] = 10^ - 10.75
[OH⁻] = 1.778 x 10⁻¹¹ M
hope this helps !
Answer:
21.8 grams.
Explanation:
Molar mass data from a modern periodic table:
- Mg: 24.301;
- O: 15.999.
How many moles of MgO will be produced if Mg is the limiting reactant?
Number of moles of Mg:
.
The ratio between the coefficient of Mg and that of MgO is 2:2. Two moles of Mg will make two moles of MgO. 0.670644 moles of MgO will be produced if Mg is the limiting reactant.
How many moles of MgO will be produced if O₂ is the limiting reactant?
Number of moles of O₂:
.
The ratio between the coefficient of O₂ and that of MgO is 1:2. One mole of O₂ will make two moles of MgO. of MgO will be produced if O₂ is in excess.
How many moles of MgO will be produced?
0.541284 is smaller than 0.670644. Only 0.541284 moles of MgO will be produced since O₂ will run out before all 16.3 grams of Mg is consumed.
What's the mass of 0.541284 moles of MgO?
Formula mass of MgO:
.
Mass of 0.541284 moles of MgO:
.