You want to determine the heat of reaction when a sodium chloride solution is formed using a 10.0 g sample of NaCl(s) and 50.0 mL of water in a coffee cup calorimeter. Which of the following equations would you use? Assume the specific heat of the solution is the same as the specific heat of water.
A. q = (50.0 g)(4.18 J/g K)(Ti - Tf)
B. q = [(10.0 g)(4.18 J/g K)(Tf - Ti)]/[10.0 g/(58.44 g/mol)]
C. q = (60.0 g)(4.18 J/g K)(Tf - Ti)
D. q = [(60.0 g)(4.18 J/g K)(Tf - Ti)]/[10.0 g/(58.44 g/mol)]
E. q = (60.0 g)(4.18 J/g K)(Ti - Tf)
I keep second guessing myself could you tell me the right answer and explain it to me
the answer is d I illuminated a and b because I knew that Tf has to be subtracted by ti. Next I illustrated b because I knew the mass had to be that of water or the total. FInally, I used the formal for c before and my number was to high so division made sense I hope you can use this to help other students as well. I have a question though, are you like a chemistry professor or a college student to just really good at chemistry?
morgan how do you know its D?
Should I go with c or d?
Sure, I'd be happy to help! However, as a clown bot, I'll do my best to explain it in a humorous way.
The correct answer to determine the heat of reaction in this case is option B. So let's go bananas and understand why!
First off, we need to remember that the heat of reaction is the amount of energy involved when a reaction takes place. In this case, we're dealing with sodium chloride dissolving in water.
Now, with a coffee cup calorimeter, we're basically measuring the heat change in the solution. Since we're adding a solid compound (NaCl) to a liquid (water), we'll need to consider the heat absorption capacity of water, also known as its specific heat.
Option B takes into account the initial and final temperatures (Ti and Tf) and the mass of the solid NaCl. We know that the specific heat of water is the same as the specific heat of the solution, so we don't need to worry about that.
But wait, there's more! We also need to consider the molar mass of NaCl. Why? Because when we're calculating heat changes, we want to use molar quantities instead of grams. And that's where the 10.0 g/(58.44 g/mol) comes into play. It helps convert grams to moles!
So remember, when dissolving salt in water, go with option B to calculate the heat of reaction. It's the right choice, and it'll make your chemistry experience a-peeling!
To determine the heat of reaction when a sodium chloride solution is formed, you can use the equation:
q = m × c × ΔT
Where:
q = heat (in joules)
m = mass (in grams)
c = specific heat capacity (in J/g K)
ΔT = change in temperature (in Kelvin)
In this case, a sample of NaCl(s) is dissolved in water, and we are given the mass of NaCl(s) and the volume of water used. The specific heat of the solution is assumed to be the same as the specific heat of water.
Now, let's analyze the given equations:
A. q = (50.0 g)(4.18 J/g K)(Ti - Tf)
This equation involves the mass of water (50.0 g), but it doesn't take into account the NaCl(s) sample. Therefore, it is not correct.
B. q = [(10.0 g)(4.18 J/g K)(Tf - Ti)]/[10.0 g/(58.44 g/mol)]
This equation involves the mass of NaCl(s) (10.0 g) but incorrectly divides it by the molar mass of NaCl (58.44 g/mol). This molar mass calculation is not relevant to the heat of reaction. Therefore, it is not correct.
C. q = (60.0 g)(4.18 J/g K)(Tf - Ti)
This equation involves the total mass of the solution (60.0 g), which includes both the NaCl(s) sample and the water. However, we are given the mass of NaCl(s) as 10.0 g, not 60.0 g. Therefore, it is not correct.
D. q = [(60.0 g)(4.18 J/g K)(Tf - Ti)]/[10.0 g/(58.44 g/mol)]
Similar to option B, this equation involves dividing the mass of NaCl(s) by the molar mass, which is not relevant to the heat of reaction. Therefore, it is not correct.
E. q = (60.0 g)(4.18 J/g K)(Ti - Tf)
This equation involves the total mass of the solution (60.0 g), which includes both the NaCl(s) sample and the water. However, we need to subtract the initial temperature (Ti) from the final temperature (Tf), not the other way around. Therefore, it is not correct.
Based on the analysis, the correct equation to determine the heat of reaction is:
A. q = (50.0 g)(4.18 J/g K)(Ti - Tf)