A 2.25 g sample of hydrazine, N2H4, is burned in a bomb calorimeter that contains 6,402.45 g of H2O, and the temperature increases from 25.00° C to 26.17° C. The heat capacity of the calorimeter is 3.64 kJ/° C. Calculate Delta E for the combustion of N2H4 in kJ/g.
25-26.16 = -1.17
q1=(6402.45 * 4.184 * -1.17)/1000=-A KJ
q2 = 3.64 * -1.17 = -B KJ
Delta_E = (q1 + q2)/2.25 = - C KJ/g
To calculate ΔE for the combustion of N2H4, we need to determine the heat transferred to the water in the calorimeter.
First, let's calculate the heat transferred to the water using the formula:
q = m * c * ΔT
where q is the heat transferred, m is the mass of the water, c is the specific heat capacity of water, and ΔT is the change in temperature.
Given:
Mass of water (m) = 6,402.45 g
Specific heat capacity of water (c) = 4.18 J/g °C
Change in temperature (ΔT) = (26.17 °C - 25.00 °C) = 1.17 °C
q = 6,402.45 g * 4.18 J/g °C * 1.17 °C
Now, convert the heat transferred to kJ by dividing by 1000:
q = (6,402.45 g * 4.18 J/g °C * 1.17 °C) / 1000
Next, we need to take into account the heat capacity of the calorimeter. The heat transferred to the calorimeter (ΔE_calorimeter) is determined by the heat capacity of the calorimeter (C_calorimeter) and the change in temperature (ΔT):
ΔE_calorimeter = C_calorimeter * ΔT
Given:
Heat capacity of the calorimeter (C_calorimeter) = 3.64 kJ/°C
Change in temperature (ΔT) = (26.17 °C - 25.00 °C) = 1.17 °C
ΔE_calorimeter = 3.64 kJ/°C * 1.17 °C
Now, we can calculate the ΔE for the combustion of N2H4 by subtracting the heat transferred to the calorimeter from the heat transferred to the water:
ΔE = q - ΔE_calorimeter
Finally, calculate ΔE in kJ/g by dividing ΔE by the mass of N2H4:
ΔE_combustion = ΔE / mass of N2H4
Given:
Mass of N2H4 = 2.25 g
ΔE_combustion = (q - ΔE_calorimeter) / 2.25 g
Now, just plug in the values and calculate ΔE_combustion.
To calculate the Delta E for the combustion of N2H4 in kJ/g, we will need to use the formula:
Delta E = q / m
Where:
- Delta E is the change in energy (in kJ)
- q is the heat absorbed or released during the reaction (in kJ)
- m is the mass of the substance (in grams)
First, we need to calculate the heat absorbed or released during the reaction (q). To do this, we can use the equation:
q = C * ΔT
Where:
- q is the heat absorbed or released during the reaction (in kJ)
- C is the heat capacity of the calorimeter (in kJ/°C)
- ΔT is the change in temperature (in °C)
In this case, the heat capacity of the calorimeter (C) is given as 3.64 kJ/°C, and the change in temperature (ΔT) can be calculated by subtracting the initial temperature from the final temperature:
ΔT = (26.17°C - 25.00°C) = 1.17°C
So, q = (3.64 kJ/°C) * (1.17°C) = 4.2548 kJ
Next, we need to determine the mass of hydrazine (N2H4). The mass of N2H4 is given as 2.25 g.
Now we can calculate Delta E:
Delta E = q / m = (4.2548 kJ) / (2.25 g) = 1.89 kJ/g
Therefore, the Delta E for the combustion of N2H4 is 1.89 kJ/g.