Purpose:
The purpose of the experiment is to find the heat solution for sodium sulphate dehydrate (Na2SO4.10H2O)
Discussion:
It is given that the volume and density of the taken water is 25 ml and 0.99826 g / ml respectively. From the values of density and volume, the mass of the water can be calculated. Using the formula,
Density = mass / volume;
the mass of the water can be determined and here it is calculated to be 24.957 g. Initial temperature and final temperature are given here and these are 19.7 ° C and 24.2 ° C respectively. It is also given that the mass of the paper and the pass of the paper including the solid are 0.965 g and 3.051 respectively. Hence, by subtracting these two terms, the mass of the solid can be obtained and it is 2.086 g.
Now using the formula, Heat = mass × specific heat × ∆t, the gain or loss of heat can be calculated.
Calculation for water:
Heat = mass × specific heat × ∆t = 24.957 × 4.184 × 4.5 = 469.89
Calculation for water:
Heat = mass × specific heat × ∆t = 2.086 × 0.8368 × 4.5 = 7.855
Hence,
∆H = 469.89 + 7.855 = 477.745
∆H per gram solid = 7.855 / 2.086 = 3.766
The formula molar mass is given 249.3 g / mol.
∆H per mole = 62.150 kJ / mole
This process is an endothermic process. As the value of ∆H is positive, the process is an endothermic process.
If some solute did not dissolve, it would affect the result. If the solute had been dissolved entirely, it would have released more heat.
Three possible sources of error are given below:
Human error.
Measurement error.
Instrumentation limitations.
