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Chemistry Question

I need desperate help with my chemistry assignment:

"Calculate the energy changes that take place during exothermic and endothermic reactions."

I have to apply this question to my own results which are below:

"1. The substances used for first investigation were hydrochloric acid and sodium hydroxide. The hydrochloric acid had an initial temperature of 24°c and the sodium hydroxide had a temperature of 22°c. Once the two substances had been mixed, the temperature increased to 30°c."

To answer the question, I have to use the equation Q = mcΔT
Original post by powiful
I need desperate help with my chemistry assignment:

"Calculate the energy changes that take place during exothermic and endothermic reactions."

I have to apply this question to my own results which are below:

"1. The substances used for first investigation were hydrochloric acid and sodium hydroxide. The hydrochloric acid had an initial temperature of 24°c and the sodium hydroxide had a temperature of 22°c. Once the two substances had been mixed, the temperature increased to 30°c."

To answer the question, I have to use the equation Q = mcΔT


Is a mass m in form of a unit given? I can't read this out from the text. Otherwise you can't solve this maths word problem with this formula.
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powiful
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Original post by Kallisto
Is a mass m in form of a unit given? I can't read this out from the text. Otherwise you can't solve this maths word problem with this formula.


There’s no mass which is why I’m so confused 🤔
Original post by powiful
There’s no mass which is why I’m so confused 🤔


Maybe the mass results in the atomic masses of the substances in total, but this makes no sense in my opinion. So I have not the slightest clue like you.
Original post by powiful
There’s no mass which is why I’m so confused 🤔


the "mass" is essentially the mass of the whole solution which can be approximated and estimated by measuring the volume of the solutions you have used. You have to assume the solutions have the density of water which is 1 g/cm3 . SO unless you have measured the volumes of NaOH and HCl, you can't really do that calculation.

ΔT = change in temperature (ideally you really should've waited till the HCl and NaOH solution were at the same temperature so I suggest taking an average)

c = 4.18 J/g/K (specific heat capacity of water).

So again unless you know the volumes of the solutions, you can't work out Q.

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