The Melting Point Of Urea And Trans-Cinnamic Acids

The melting point of a substance is best described as the temperature at which a solid becomes a liquid (Bruice 2014). On the molecular level, when a compound melts the forces between the molecules become weaker. This is because when a substances heats up the kinetic energy between the molecules increase causing the molecules to vibrate. When the vibrations become strong enough for the molecules to move around and pass other molecules, the compound that is being heated up starts to melt and become a liquid. In this lab, five different ratios of two chemical solids, Urea and trans¬-cinnamic acid, were heated up in a Mel Temp apparatus until the final melting point was achieved. Each substance started as a solid in a capillary tube and when they reached the …show more content…
From the experiment, it was determined that pure urea had a melting point of 131.2 ˚C -136.6 ˚C which falls within range of the normal melting temperature of pure urea, meaning that error occurred. Trans-cinnamic acids melting point was determined to be 133.4 ˚C -135 ˚C, which falls out of the normal melting tempature by 0.4 ˚C meaning that error must have occurred in that section of the experiment. In the lab another three samples were analyzed using different ratios of urea and trans-cinnamic acid, these mixtures all were found to have different melting point values. The sample that contained 90% Urea and 10% trans-cinnamic acid had a melting point range of 115.4 ˚C -133.4 ˚C, this value is lower than both the pure urea and pure trans-cinnamic acid. The mixture that was 50% Urea, 50% trans-cinnamic acid had the lowest melting point in the experiment. The value for the 1:1 substance was found to be between 95.8 ˚C -98.5 ˚C. The substance that was 10 % urea, 90% trans-cinnamic acid had a melting temperature of 126.7 ˚C -133.3 ˚C, making it lower than both pure