The burning of magnesium is a highly exothermic reaction. How many kilojoules of heat are released when 0. 75 mol of Mg burn in
1 answer:
Taking into account the definition of enthalpy of a chemical reaction, the quantity of heat released when 0.75 moles of Mg are burned is 451.5 kJ.
<h3>Enthalpy of a chemical reaction</h3>The enthalpy of a chemical reaction is known as the heat absorbed or released in a chemical reaction when it occurs at constant pressure. That is, the heat of reaction is the energy that is released or absorbed when chemicals are transformed into a chemical reaction.
The enthalpy is an extensive property, that is, it depends on the amount of matter present.
<h3>Heat released in this case</h3>In this case, the balanced reaction is:
2 Mg(s) + O₂ (g) → 2 MgO(s) + 1204 kJ
This equation indicates that when 2 moles of Mg reacts with 1 mole of O₂, 1204 kJ of heat is released.
When 0.75 moles of Mg are burned, then you can apply the following rule of three: if 2 moles of Mg releases 1204 kJ of heat, 0.75 moles of Mg releases how much heat?
<u><em>heat= 451.5 kJ</em></u>
Finally, the quantity of heat released when 0.75 moles of Mg are burned is 451.5 kJ.
Learn more about enthalpy of a chemical reaction:
<u>brainly.com/question/15355361</u>
<u>brainly.com/question/16982510</u>
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Answer:
the final volume of the gas is = 1311.5 mL
Explanation:
Given that:
a sample gas has an initial volume of 61.5 mL
The workdone = 130.1 J
Pressure = 783 torr
The objective is to determine the final volume of the gas.
Since the process does 130.1 J of work on its surroundings at a constant pressure of 783 Torr. Then, the pressure is external.
Converting the external pressure to atm ; we have
External Pressure :
The workdone W = V
The change in volume ΔV=
ΔV =
ΔV =
ΔV = 1.25 L
ΔV = 1250 mL
Recall that the initial volume = 61.5 mL
The change in volume V is
multiply through by (-), we have:
= 1250 mL + 61.5 mL
= 1311.5 mL
∴ the final volume of the gas is = 1311.5 mL
Answer : The rate constant at 785.0 K is,
Explanation :
According to the Arrhenius equation,
or,
where,
= rate constant at
=
= rate constant at
= ?
= activation energy for the reaction = 262 kJ/mole = 262000 J/mole
R = gas constant = 8.314 J/mole.K
= initial temperature =
= final temperature =
Now put all the given values in this formula, we get:
Therefore, the rate constant at 785.0 K is,