A10.1 g sample of naoh is dissolved in 250.0 g of water in a coffee-cup calorimeter. the temperature increases from 23.0 °c to °c. specific heat of liquid water is 4.18 j/g-k and δh for the dissolution of sodium hydroxide in water is 44.4 kj/mol.

33.3 °C

Explanation:

You have two heat flows in this experiment.

Heat from solution of NaOH + heat to warm water = 0

                     q1                       +               q2               = 0

                   nΔH                     +             mCΔT           = 0

Data:

m(NaOH) = 10.1 g

            ΔH = -44.4 kJ/mol

 m(H2O) = 250.0 g

              C = 4.18 J/(K·mol)

            Ti = 23.0 °C

Calculation:

n = 10.1 g NaOH × (1 mol NaOH/40.00g NaOH = 0.2525 mol NaOH

q1 = 0.2525 mol × (-44 400 J/mol) = -11 210 J

m(solution) = m(NaOH) + m(water) = 10.1 + 250.0 = 260.1g

q2 = 260.1 × 4.18 × ΔT = 1087ΔT J

-11 210 + 1087ΔT = 0

                   1087ΔT = 11 210

                             ΔT = 11 210/108745 = 10.31 °C

ΔT = T2 - T1 = T2 - 23.0 = 10.73

                                      T2 = 23.0 + 10.31 = 33.3 °C

The temperature increases to 33.3 °C.

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%

it should have an internal chamber and two thermometers sticking out of the top. the internal chamber will also be closed off from the outside.