melting point of benzoic acid
Before knowing the melting point of benzoic acid, we should know the definition of melting point. Temperature at which the solid and liquid states of a pure substance can exist in equilibrium. As heat is applied to a solid, its temperature increases until it reaches the melting point. At this temperature, additional heat converts the solid into a liquid without a change in temperature. The melting point of solid water (ice) is 32°F (0°C). The melting point of benzoic acid is 122.4 degree Celsius.
Determining the melting point of benzoic acid
1. To determine the melting point of benzoic acid, make sure the melting point device is close to room temperature before beginning a melting point analysis.
2. To determine the melting point of benzoic acid, using a spot plate and the butt end of a test tube or a mortar and pestle, grind the sample of benzoic acid into a fine powder. Pack it into a glass capillary tube so that the level of powder is about 2 mm high.
3. To determine the melting point of benzoic acid, turn the capillary so that the closed end is down. Pack it tightly by dropping it through a long tube over the lab bench or tapping it on the bench directly.
4. To determine the melting point of benzoic acid, set the melting point device to a temperature that will create relatively slow heating. Mel-Temp devices have a setting that reaches maximum temperature at 1,000 degrees C and another that reaches maximum at 200 degrees C.
5. To determine the melting point of benzoic acid, determining this setting can be complicated, but a good rule of thumb is to keep the rate of heating to a slow enough paces to avoid missing valuable data. You should lower the heating rate as the expected melting point comes closer.
6. To determine the melting point of benzoic acid, observe the benzoic acid's melting point in the device. Look through the eyepiece, wearing goggles, and glance away briefly to check and record the temperature in your lab notebook every time a change is noted. Material might "sweat" before its melting point.
What two effects do impurities have on the melting point of organic compounds?
An impurity causes the melting point to deviate from the standard. Actually, it makes the magnitude of the melting point lower. For example, the melting point of benzoic acid is 122.4 degree Celsius. When we did this in the laboratory, we got 120 degree Celsius because of the impurity present. So, those are the two effects that impurities have on melting point of a pre compound. It is because the impurities "defect" the crystal lattice of the compound. If the impurities are present with the pure compound, the melting point will deviate because melting point is also dependent on the high symmetry and organization of molecular structures, just as the vapor pressure.
Determining the melting point of benzoic acid
1. To determine the melting point of benzoic acid, make sure the melting point device is close to room temperature before beginning a melting point analysis.
2. To determine the melting point of benzoic acid, using a spot plate and the butt end of a test tube or a mortar and pestle, grind the sample of benzoic acid into a fine powder. Pack it into a glass capillary tube so that the level of powder is about 2 mm high.
3. To determine the melting point of benzoic acid, turn the capillary so that the closed end is down. Pack it tightly by dropping it through a long tube over the lab bench or tapping it on the bench directly.
4. To determine the melting point of benzoic acid, set the melting point device to a temperature that will create relatively slow heating. Mel-Temp devices have a setting that reaches maximum temperature at 1,000 degrees C and another that reaches maximum at 200 degrees C.
5. To determine the melting point of benzoic acid, determining this setting can be complicated, but a good rule of thumb is to keep the rate of heating to a slow enough paces to avoid missing valuable data. You should lower the heating rate as the expected melting point comes closer.
6. To determine the melting point of benzoic acid, observe the benzoic acid's melting point in the device. Look through the eyepiece, wearing goggles, and glance away briefly to check and record the temperature in your lab notebook every time a change is noted. Material might "sweat" before its melting point.
What two effects do impurities have on the melting point of organic compounds?
An impurity causes the melting point to deviate from the standard. Actually, it makes the magnitude of the melting point lower. For example, the melting point of benzoic acid is 122.4 degree Celsius. When we did this in the laboratory, we got 120 degree Celsius because of the impurity present. So, those are the two effects that impurities have on melting point of a pre compound. It is because the impurities "defect" the crystal lattice of the compound. If the impurities are present with the pure compound, the melting point will deviate because melting point is also dependent on the high symmetry and organization of molecular structures, just as the vapor pressure.