Question

Can I have an example of a question to ask to find delta H of rxn using the q equation. Using q=m*c*deltaT? Give me an example question asking about that and also show me steps on how to do it. Please step by step.

Answer 1

Yes ! You can determine 4H by using q equation. Here q is the amount of heat releases or absorbed Que: A chemistry students dissolves 4.51 gram of sodium hydroxide in 100mL of water at 19.5°C. As sod. hydroxide dissolves, temperature increases to 31.7°C. Detemine heat of solution and enthalpy change of reaction? Ans - Here first we calculate heat of reaction bu using equation below, Here, m mass of water 100 g Cp = Specific heat of water = 4.184 J/g°C AT - Change in temp 31.T°C 19.5°C 12.20C Putting this values in above equation q100 gx 4.184 J/g. °C x 12.2°C 5104.48 J It is assumption that heat gained by water is equal to the heat lost by NaOH. +ve sign of heat means heat gained and -ve means heat lost. So, heat lost by NaOH5104.48 J Now Hmmass of NaOH - 5104.48 J/4.51 g - 1131.81 JIg - 1131.81 Jig 1000 - 1.131 KJ Ig In that way we can calculate enthalp change of reaction using q value!

Here, enthalpy change = - 1.131 KJ /g