Calorimeter Experiment

Introduction

Heat is the form of energy, thermal energy, which flows between two substances due to their difference in temperature.1 The measurement of heat flow is called Calorimetry and the apparatus used to measure the heat flow (temperature change) for a reacting system is called a calorimeter. The calorimeter is well-insulated device that help to minimize the heat exchange between the system being observed and its surroundings.

In this experiment, simple calorimeter, coffer cup calorimeter containing Styrofoam cups is used. Calorimeter contains a thermometer and a stirrer.3 Thermometer is typically inserted in the calorimeter to measure the change in the temperature that results from the reaction. Stirrer is used to keep the contents

ΔH= q

Specific heat is the amount of heat needed to raise the temperature of one gram of a substance by 1 C (or 1 K).1 Specific heat of water is equal to 4.18 J/ g℃.1 In order to determine the specific heat capacity of metal, it is necessary to know mass and change in temperature, specific heat of water, also change in temperature and mass of metal used:

q_(H_2 O)=〖S.H.〗_(H_2 O) × m_(H_2 O) × ∆t_(H_2 O)= -〖S.H.〗_M × m_M ×

Firstly, 39.15 g of water was used and molar mass of metal was determined to be 61.43 g/mol, then 50.88 g of water was used and molar mass of metal was determined to be 59.24 g/mol. If the amount of water in the calorimeter varies, and thus the heat capacity of the water would vary. Firstly, specific heat capacity of metal was determined, which depends on heat of the water mass of the water and mass of the solid, then molar mass using:

MM= 25/(S.H.(J/(g℃)) )

In the Part B of the experiment q_(H_2 O) for the reaction was find to be 2279.5 joules, ∆H for the reaction = -2279.5 joules, ∆Hsolution = -455.9 joules/g. This solution reaction is exothermic; because temperature was increased meaning heat was released.

In the last part of the experiment, neutralization reaction was investigated.

NaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)

Enthalpy change for neutralization reaction between HCl and NaOH were calculated to be -51kJ. For reactions involving strong acids and alkalis, like HCl and NaOH, the values are always very closely similar, with values between -57 and -58 kJ.2 The actual value of enthalpy change of neutralization reaction is equal to -57.9 kJ.2 The reason for dissimilarity of results could be loss of heat during the transferring of the NaOH to the HCl. Since, temperature was increased, the reaction is exothermic, heat was