How much heat energy in KJ is evolved by a reaction in a calorimeter in which the temperature of the calorimeter and water increases from 20.91 degrees C to 26.45 degrees C? The bomb has a heat capacity of 469 J/degrees . The Calorimeter contaains 792 grams of water.
q = [mass water x specific heat water x delta T] +[Ccalx delta T]
specific heat of water there isnt one?
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To calculate the heat energy evolved by the reaction, you need to use the formula:
q = mcΔT
Where:
q is the heat energy evolved or absorbed by the system (in this case, the reaction)
m is the mass of the substance (in this case, the water)
c is the specific heat capacity of the substance (in this case, the water)
ΔT is the change in temperature
First, let's convert the given temperatures from degrees Celsius to Kelvin by adding 273.15:
Initial temperature (T1) = 20.91°C + 273.15 = 294.06 K
Final temperature (T2) = 26.45°C + 273.15 = 299.6 K
Now let's calculate the change in temperature (ΔT):
ΔT = T2 - T1
ΔT = 299.6 K - 294.06 K
ΔT = 5.54 K
Next, let's calculate the heat energy using the formula q = mcΔT:
q = (m)(c)(ΔT)
The mass of water (m) is given as 792 grams and specific heat capacity (c) is given as 4.19 J/g·K. However, since the given bomb heat capacity is in J/degrees, we need to convert it to J/g·K:
1 J/degrees = 1 J/g·K / 1000 = 0.001 J/g·K
Now, let's convert the heat capacity of the bomb to J/g·K:
Bomb heat capacity = 469 J/degrees * 0.001 J/g·K = 0.469 J/g·K
Now we can substitute the values into the equation:
q = (m)(c)(ΔT)
q = (792 g)(4.19 J/g·K)(5.54 K)
q = 18583.1248 J
Since the heat energy is given in Joules, you can convert it to kilojoules (KJ) by dividing by 1000:
q = 18583.1248 J / 1000 = 18.58 KJ
Therefore, the heat energy evolved by the reaction in the calorimeter is approximately 18.58 KJ.