The complete combustion of 1.00 ml of octane increases the temperature by 22.7 degrees celsius. The density of octane is 0.7g/mL. What is the efficiency of the octane in heating the water?
You have to know how much water.
Sorry. There are 250.00g of water.
find the heat of commbusion, then figure the heat from the ocatane.
Now, the water: heat to heat water:masswater*c*22
efficiency=heatforwater/heatfromoctane * 100 if you want it in percent.
I have a feeling this is just part of th question and that it refers to another question.
Increases the temperature of what 22.7 celsius? Water?
Calculate dH combustion octane.
2C8H18 + 25O2 ==> 16CO2 + 18H2O
dHrcomb(rxn) = (n*dHf products) = (n*dHf reactants) = ? = heat of combustion for octane. This is the amount of heat available (theoretical I've called it below).
Use density to convert 1.00 mL octane to grams. Mass of water octane heated is not given.
q = mass H2O x specific heat H2O x delta T = this is the actual heating accomplished.
Effeciency = [(actual heating)/theor heating)]*100 = ?
But @DrBob222 where would I find delta T? Also, mass of water is 250 grams.
delta T is 22.7. Right?
I'm getting really high negative percentage numbers.
Bob Pursley's answer and my are are the same. Post your work if you're still having trouble.
To find the efficiency of the octane in heating the water, we need to calculate the amount of heat energy released by the combustion of octane, and then compare it to the heat energy absorbed by the water.
First, we need to find the mass of octane that was burned. We can do this using the density of octane, which is given as 0.7 g/mL, and the volume of octane used, which is 1.00 mL. The mass can be calculated as follows:
Mass of octane = Density × Volume
Mass of octane = 0.7 g/mL × 1.00 mL
Mass of octane = 0.7 g
Next, we need to calculate the heat energy released by the combustion of octane. This can be done using the specific heat capacity of octane, which is 45.8 kJ/mol·°C, the molar mass of octane, which is 114.2 g/mol, and the increase in temperature, which is 22.7 °C. The heat energy can be calculated as follows:
Heat energy = (Change in temperature) × (Mass of octane) × (Specific heat capacity of octane) / (Molar mass of octane)
Heat energy = 22.7 °C × 0.7 g × 45.8 kJ/mol·°C / 114.2 g/mol
Simplifying the expression, we get:
Heat energy ≈ 9.08 kJ
Now we need to find the amount of heat energy absorbed by the water. The heat energy absorbed by water can be calculated using the specific heat capacity of water, which is 4.18 J/g·°C, the mass of water, and the increase in temperature. However, we have not been provided with the mass of water in the question.
Therefore, without the mass of water, we cannot calculate the efficiency of the octane in heating the water. We would need to know the mass of water to proceed with the calculation.
Please provide the mass of water so that we can continue with the calculation.