For the experiment of calorimeter, (the experimental methods as below), there are some differences between the standard values and the experimental values for the heat of combustion of the four alcohols: ethanol, propan-1-ol, butan-1-ol, and hexan-1-ol.

 

Explain how these differences between the standard values and experimental values occur? And why these errors affect the data collected and calculated?

 

 

 

Experimental Procedure Method 

 

1. Measure 100cm3 of water using the measuring cylinder. Pour this water into the steel can and record its temperature. 2. Take one of the spirit burners and record • the name of the fuel • the mass of the whole burner (including the lid and fuel inside). 3. Clamp the steel can at a suitable height, so that the spirit burner will fit comfortably under it. 4. Light the wick of the spirit burner, and put it under the steel can. 5. Stir the water gently with the thermometer, and watch the temperature. 6. When it has increased by 20°C, put the lid on the spirit burner to put the flame out. 7. Record the new mass of the whole burner (including the lid and fuel inside) and any observations. 8. Using fresh water each time, repeat the experiment for all the other spirit burners containing the other alcohols. 

It is possible that there are several causes of error contributing to the variations between standard and experimental figures for the heat of combustion of the four alcohols. The variance in the masses of the burners is a significant cause of inaccuracy. When the water was stirred, the thermometer was not always at the same depth, resulting in the temperature being taken at various spots in the water each time. Also influenced was the rate of combustion, and thus the rise in temperature.

Step-by-step explanation

• The first reason why the standard values and experimental values differ is because the standard values are theoretical values, while the experimental values are actual values. The second reason is because the experiment is not conducted in a closed system, which means that there is some heat loss that occurs.
• This is due to the fact that the steel can is not airtight, and the heat from the burning alcohol escapes from the can. The third reason is because the different alcohols have different masses, and so they release different amounts of heat when they are burned.
• The fourth reason is because the wicks of the spirit burners are not exactly the same, and so they burn differently. This results in different amounts of heat being released from the alcohols. All of these factors contribute to the differences between the standard values and experimental values, and they all affect the data collected and calculated.
• The differences between the standard values and experimental values for the heat of combustion of the four alcohols are due to several sources of error. One major source of error is the variation in the masses of the burners.
• When the steel can was clamped to the stand, it was not always at the same height, which affected the distance of the burner from the can. This affected the rate of combustion, and therefore the temperature increase.
• The measured masses of the burners also varied, which resulted in different heat of combustion values. Another source of error was the different volumes of water in the can. When stirring the water, the thermometer was not always at the same depth, which caused the temperature to be measured at different points in the water.
• This also affected the rate of combustion, and therefore the temperature increase. The final source of error was the variation in the initial temperatures of the water. When the water was poured into the can, it was not always at the same temperature. This affected the heat of combustion, as it was measured at different temperatures. All of these sources of error affected the data collected and calculated. The errors caused the values for the heat of combustion to vary, and therefore the results were not accurate.