The right answer is A rapid temperature increase will give a melting point range that is too high.
The melting point is determined in a capillary tube. it means the temperature at which the substance is completely melted, indicated by the disappearance of the solid, will not differ by ± 4 ° C from the given value, unless otherwise indicated.
The following technique can be applied to determine the melting point:
Grind some amount of substance in a small mortar. Place in a vacuum desiccator containing silica gel or phosphorus pentoxide and allow to dry for 24 hours at room temperature (unless another method of drying is indicated in the test protocol) . Introduce the substance into a dry capillary tube 1 mm inside diameter to form a column about 3 mm high. Heat the melting device to a temperature 5 to 10 ° C below the expected melting temperature and adjust the heating so that the temperature of the enclosure rises by approximately 1 ° C per minute. Introduce the capillary tube containing the substance into the heated chamber and note the temperature at which the agglomerated substance becomes completely transparent; this temperature constitutes the melting point.
B second year. The number of tree rings can tell how old a tree is, but the thickness of those rings also says something about the amount of water available in a given year. Wider rings mean the tree received more water that year. Thinner rings mean water was scarce.
