When 5.000 g of nahco3 is added to 600.0 g of water in a ‘coffee cup calorimeter’, the temperature decreases from 22.35°c to 18.94°c. a) calculate qcalorimeter, in joules, assuming the specific heat capacity of the solution is the same as pure water: 4.186 jg-1k-1. report your value to 4 significant figures, and do not include units in your answer.

Answer is: qcalorimeter is 8635.9273 J.

ΔT= 22.35°C - 18.94°C.

ΔT = 3.41°C = 3.41 K; temperature change.  

m(H₂O) = 600.0 g; mass of water.  

mr = 605.0; mass of solution.

cp= 4.186 J/g·K, specific heat capacity of the solution.  

qcal = mr · ΔT· cp.  

qcal = 605 g · 3.41 K · 4.186 J/g·K.  

qcal = 8635.9273 J; amount of heat absorbed.

1. for the first question, we must find the mass of the anhydrous salt, mgso₄. the molar mass for mgso₄·7h₂o is 246.47 g/mol, while that of mgso₄ is 120.37 g/mol.7.834 g mgso₄·7h₂o * 1 mol mgso₄·7h₂o/246.47 g * 1 mol mgso₄/1 mol mgso₄·7h₂o * 20.37 g mgso₄/mol = 0.647 g mgso₄

2. mass of water = mass of sample - mass of anhydrous salemass of water = 7.834 - 0.647 = 7.19 gpercent water in hydrate = 7.19/7.834 * 100 = 91.74%