When a 0.650 g sample of a mixture of volatile hydrocarbons is burned in a bomb calorimeter with a heat capacity of 4920 J/°C, the temperature rises by 8.50 °C.
What is the change in energy (in kilojoules) for the reaction?
Calculate the energy change by the combustion of a 6.00 g sample of the same mixture.
Thank you so much!
To calculate the change in energy for the reaction, we can use the formula:
Change in energy = (mass of sample) * (specific heat capacity) * (change in temperature)
Given:
Mass of the sample = 0.650 g
Specific heat capacity of the calorimeter = 4920 J/°C
Change in temperature = 8.50 °C
Change in energy = (0.650 g) * (4920 J/°C) * (8.50 °C)
Change in energy = 27762 J
To convert the energy to kilojoules, we divide by 1000:
Change in energy = 27.762 kJ
Therefore, the change in energy for the reaction is 27.762 kJ.
To calculate the energy change for the combustion of a 6.00 g sample of the same mixture, we can use the concept of proportionality. Since the mass of the sample has changed, we need to find the ratio of the masses and multiply it with the previous energy change.
Mass of the first sample = 0.650 g
Mass of the second sample = 6.00 g
Ratio of masses = (mass of the second sample) / (mass of the first sample)
Ratio of masses = (6.00 g) / (0.650 g)
Ratio of masses = 9.23
Energy change for the combustion of the second sample = (Ratio of masses) * (Change in energy)
Energy change for the combustion of the second sample = (9.23) * (27.762 kJ)
Energy change for the combustion of the second sample = 255.935 kJ
Therefore, the energy change for the combustion of a 6.00 g sample of the same mixture is 255.935 kJ.
To calculate the change in energy for the reaction, we can use the formula:
ΔE = q + w
Where:
ΔE = Change in energy
q = Heat absorbed or released by the system
w = Work done on or by the system
In this case, we are burning a sample of hydrocarbons in a bomb calorimeter, so there is no work done (w = 0). Therefore, the formula simplifies to:
ΔE = q
To calculate the heat absorbed or released by the system (q), we can use the equation:
q = CΔT
Where:
C = Heat capacity of the calorimeter
ΔT = Change in temperature
Given values:
C = 4920 J/°C
ΔT = 8.50 °C
Substituting these values into the equation, we get:
q = (4920 J/°C)(8.50 °C)
q = 41820 J
Now, to convert this to kilojoules, divide by 1000:
q = 41.82 kJ
Therefore, the change in energy for the reaction is 41.82 kJ.
To calculate the energy change by the combustion of a 6.00 g sample of the same mixture, we can use the principle of proportionality. Since the change in energy is directly proportional to the mass of the sample, we can set up a proportion:
Change in energy (6.00 g) = Change in energy (0.650 g)
Let's call the change in energy for the new sample "ΔE2". Setting up the proportion:
ΔE2 / 6.00 g = 41.82 kJ / 0.650 g
Now, cross-multiply and solve for ΔE2:
ΔE2 = (6.00 g)(41.82 kJ) / 0.650 g
ΔE2 ≈ 384.92 kJ
Therefore, the energy change by the combustion of a 6.00 g sample of the same mixture is approximately 384.92 kJ.
change in engery=8.50*4920 J
what is 6.0/.650 * energy change above