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# A2 /Expt /Thermal /John/ Fred

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### A2 /Expt /Thermal /John/ Fred

1. 1. Electrical methods to determine specific heat capacity of water A21 E ditor: Fred Critical thinker: John
2. 2. Diagram and set of equipments
3. 3. Steps to be followed <ul><li>W eigh the empty calorimeter to get mass(m 1 ),fill the calorimeter with water to get mass(m 2 ). </li></ul><ul><li>I nsert the digital thermometer and heat coil into the calorimeter to get change in temperature ( ∆ t) and change in heat ( ∆Q ) , put it in the lagging and put the cover on the calorimeter to prevent heat loss. </li></ul><ul><li>C onnect heat supply and joule meter with electric coil. </li></ul>
4. 4. Method to collect data <ul><li>Find the mass of water (m w )=mass of calorimeter with water(m 1 )-mass of calorimeter without water(m 2 ) </li></ul><ul><li>E.g. (m w )=0.200kg(m 1 )-0.100(m 2 )=0.100kg </li></ul><ul><li>Find the change in temperature ( ∆t)=final temperature(t 1 )- initial temperature(t 2 ) </li></ul><ul><li>E.g. ( ∆t )=30 0 c(t 1 )-20 o c(t 2 )=10 o c </li></ul><ul><li>Find the change in heat ( ∆Q )=final heat(Q1)-initial heat(Q2) </li></ul><ul><li>E.g. ( ∆Q)=5000J(Q1)-2000J(Q2)=3000J </li></ul><ul><li>According to the equation Q=mc ∆t c=Q/m ∆t </li></ul><ul><li>C =3000J/(0.100kg x 10K)=3.0 x 10 3 Jkg -1 K -1 </li></ul>
5. 5. Safety Measures <ul><li>Do not set too high voltage on power supply </li></ul><ul><li>Make sure the thermometer is far from the heat coil to prevent the break of thermometer. </li></ul>
6. 6. Method to reduce error <ul><li>Use a calorimeter with small capacity to prevent heat loss. </li></ul><ul><li>Repeat the experiment to get accurate results. </li></ul>