Question

PART IV MOLAR MASS OF SOLID Mass of Calorimeter (g) 10%1841 991565p S10005 Mass of Calorimeter plus water (g) Mass of water (g) Mass of unknown solid (g) alig'c 28.3 Initial temperature (°C) Final temperature (C) Temperature change (AT) Heat, q (kJ) Heat of solution per gram of solid (kJ/g) Heat of solution per mole of compound (kJ/mol) DATA ANALYSIS 1. Calculate q solution (Cs for water is 4.184 J/g°C) 2. Identify if your solution exothermic or endothermic. Give your reasoning. 3. Calculate the heat of solution per gram of sample. (KJ/g) 4. Calculate heat of solution per mole of compound (kJ/mol)

The molar mass of solid is 110.98 g/mol

Answer 1

Total mass=mass of unknown solid+ mass of water

=99.5656+5.0005=104.5661g

We know :

Q= m×c×∆T.

Where m= total mass ,c=specific heat capacity,∆T=change in Temperature

(1)Q= 104.5661g×4.18j/g°C×6.5°C

=2841.0609j

= 2.8410Kj

(2) As Q as well as ∆T is positive so it signifies that reaction is endothermic.

(3) heat of solution per gram of sample = 2.8410/5.0005=0.56814Kj/g

(4)

mass of sample=5.0005g

Molar mass of solid = 110.98g/mol

Moles of solid= 5.0005g/110.98g/mol=0.04505mol

Heat of solution per mole = 2.8410/0.04505=63.06326kj/mol