Burning alcohols to heat up a can of water

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In this investigation I will be burning alcohol's to heat up a can of water. I will be burning four alcohol's, methanol, ethanol, propanol and butanol. The aim is to find out how much energy is produced when burning these alcohols.  Alcohol's react with oxygen in the air to form water and carbon dioxide.

       The reaction that is involved in burning alcohols is exothermic because heat is given out. From this reason the reactant energy is higher than that of the product.              

       The energy is given out when forming the bonds between the new water and carbon dioxide molecules. The amount of energy produced by such exothermic reactions can be calculated by using the formula Mass of the substance x rise in temp x SHC (specific heat capacity). The specific heat capacity is the number of joules required to heat one gram of water by 1°C. I chose to use water because it is safe, easily found, and has a reliable specific heat capacity of 4.2. I will also need to ensure that I conduct the experiments safely. As alcohol's are very dangerous and highly flammable I will wear my safety goggles at all times. I will need to keep all lose items off clothing tucked in. the lids on the alcohol’s must be kept on at all times to prevent evaporation or any spillage’s.

 

Apparatus

 

·        Clamp

·        Beaker

·        Crucible

·        Measuring cylinder

·        Weight scales

·        Aluminium soft drinks can

·        Thermometer

 

The method that I will use is as follows…

 

·        Measure 150cm of water into a can beaker.

 

·        Place the can into the grasp of the clamp stand.

 

·        Record the starting temperature of the water.

 

·        Weigh the crucible, then weigh the alcohol to as near as possible 0.5 grams.

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·        Put the chosen alcohol under the beaker allowing the flame to just touch the beaker.

 

·        Leave to heat up until the alcohol evaporates.

 

·        Take the temperature when the alcohol has evaporated.

 

·        Record the temperature of the water now.

 

 

The variables that must remain constant throughout the experiment are…

 

·        Mass of the water 150ml

·        Type of can, metal, aluminium.

·        Surrounding temperature of around 21°C.

·        The height of the can from the crucible.

·        Same set of scales.

·        I will stir the water with the thermometer ...

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