SECTIONA Answer all questions. Write your answers in the boxes provided. 1. (a)
ID: 1046124 • Letter: S
Question
SECTIONA Answer all questions. Write your answers in the boxes provided. 1. (a) Two chemistry students wished to determine the enthalpy of hydration of anhydrous magnesium sulfate. They measured the initial and the highest temperature reached when anhydrous magnesium sulfate, MgSO,(s), was dissolved in water. They presented their results in the table below. mass of anhydrous magnesium sulfate /g volume of water/cm initial temperature / C highest temperature 3.01 50.0 17.0 26.7 (i) Calculate the amount, in mol, of anhydrous magnesium sulfate. (ii) Calculate the enthalpy change, water, in kJmol". State your answer to the correct number of significant figures. for anhydrous magnesíurn sulfate dissolving in (21 (This question continues on the following page)Explanation / Answer
Number of moles
Mass of substance taken in gram/ molecular weight of substance in gram
3/120.366 =0.24924
Heat liberated on dissolving 3 gram MgSO4
Specific heat capacity of water = 4.184 joules
Quantity of heat = c M ?T
= 4.184 × 50 × (26.7-17)
= 4.184 × 50 × 9.7
= 2029 Joules
Ie,
2.029 KJ of heat energy is liberated when 0.24924 moles of anhydrous MgSO4 dissolves In 50 mL of water.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.