A student mixes two water solutions with an initial temperature of 25 degrees C to form a final substance with a mass of 65 grams at 30 degrees C. What is the heat change in kJ?
mass of final soln x specific heat soln x delta T = heat change.
65 g x specific heat x 5 = q.
To calculate the heat change, we can use the equation:
Q = m * c * ΔT
Where:
Q = heat change in Joules
m = mass of the substance in grams
c = specific heat capacity of water (4.18 J/g°C)
ΔT = change in temperature in degrees Celsius
First, we need to calculate the change in temperature (ΔT). The initial temperature is 25°C, and the final temperature is 30°C. So,
ΔT = final temperature - initial temperature
= 30°C - 25°C
= 5°C
Next, we can substitute the values into the formula:
Q = 65 g * 4.18 J/g°C * 5°C
Calculating this gives:
Q = 1361.5 J
To convert Joules to kilojoules (kJ), we divide by 1000:
Q = 1361.5 J / 1000
= 1.3615 kJ
Therefore, the heat change is approximately 1.3615 kJ.
To calculate the heat change in this scenario, we need to use the equation:
q = mcΔT
where:
q is the heat change in joules
m is the mass of the substance in grams
c is the specific heat capacity of the substance in J/g°C
ΔT is the change in temperature in °C
First, let's calculate the mass of the substance. We are given that the final substance has a mass of 65 grams.
Next, we need the specific heat capacity of the substance. Since the substance is water, we can use the specific heat capacity of water, which is approximately 4.18 J/g°C.
Now, let's find the change in temperature. The initial temperature of the mixture is 25 degrees Celsius, and the final temperature is 30 degrees Celsius. Therefore, the change in temperature (ΔT) is 30 - 25 = 5 degrees Celsius.
Now, we can substitute the values into the equation:
q = mcΔT
q = 65g * 4.18 J/g°C * 5°C
Calculating this expression gives us the heat change (q) in joules.
However, the question asks for the answer in kilojoules, so we need to convert from joules to kilojoules. Since 1 kilojoule (kJ) is equal to 1000 joules (J), we can divide the heat change value in joules by 1000 to convert to kilojoules.
Finally, we have our answer in kilojoules.