The complete combustion of butane, (g) is represented by the equation
C4H10+ 13/2O2->4CO2+5H2O
standard enthalpy is -2877kj
How much heat, in kilojoules, is evolved in the complete combustion of
12.8ml at 23.8degrees celsius and 744mmhg ?
see above
To determine the amount of heat evolved in the complete combustion of 12.8 mL of butane, we can use the equation:
Q = n * ΔH
Where:
Q = heat evolved (in kilojoules)
n = number of moles of butane
ΔH = standard enthalpy of combustion of butane (in kilojoules per mole)
To find the number of moles of butane, we can use the ideal gas law:
PV = nRT
Where:
P = pressure (in atm)
V = volume (in liters)
n = number of moles
R = gas constant (0.0821 L * atm / mol * K)
T = temperature (in Kelvin)
First, convert the given volume from mL to liters:
12.8 mL = 12.8 / 1000 = 0.0128 L
Convert the given temperature from Celsius to Kelvin:
23.8°C = 23.8 + 273.15 = 296.95 K
Convert the given pressure from mmHg to atm:
744 mmHg = 744 / 760 = 0.9789 atm
Now, we can substitute the given values into the ideal gas law equation:
(0.9789 atm) * (0.0128 L) = n * (0.0821 L * atm / mol * K) * (296.95 K)
Solving for n:
n = (0.9789 atm * 0.0128 L) / (0.0821 L * atm / mol * K * 296.95 K)
n ≈ 0.000531 mol
Next, we can calculate the heat evolved using the equation:
Q = n * ΔH
Q = (0.000531 mol) * (-2877 kJ/mol)
Q ≈ -1.526 kJ
Therefore, approximately -1.526 kilojoules of heat is evolved in the complete combustion of 12.8 mL of butane at 23.8°C and 744 mmHg.
To calculate the heat evolved in the complete combustion of butane, we need to use the equation:
C4H10 + 13/2O2 -> 4CO2 + 5H2O
Given information:
Volume of butane = 12.8 mL
Temperature = 23.8 degrees Celsius
Pressure = 744 mmHg
To calculate the heat evolved, we need to convert the volume of butane to moles. To do this, we need to use the ideal gas law equation:
PV = nRT
PV = (pressure) * (volume)
R = ideal gas constant = 0.0821 L atm/(mol K)
T = temperature in Kelvin
Converting temperature from Celsius to Kelvin:
T(K) = T(C) + 273.15
T(K) = 23.8 + 273.15 = 297.95 K
Converting pressure from mmHg to atm:
Pressure(atm) = Pressure(mmHg) / 760
Pressure(atm) = 744 / 760 = 0.97894 atm
Now, let's calculate the moles of butane:
PV = nRT
n = PV / RT
n = (0.97894 atm * 0.0128 L) / (0.0821 L atm/(mol K) * 297.95 K)
n = 0.0048 mol
According to the balanced equation, for every 1 mole of butane, 2877 kJ of heat is evolved.
Therefore, we can calculate the heat evolved for 0.0048 mol of butane:
Heat evolved = (0.0048 mol) * (-2877 kJ/mol) = -13.82 kJ
So, the heat evolved in the complete combustion of 12.8 mL of butane at 23.8 degrees Celsius and 744 mmHg is approximately -13.82 kJ.