A pure white crystalline compound was found to melt at 112.5-113.0oC when taken on a melting point apparatus, and on further hea
ting, the liquid was found to turn brown at ca. 145-150 oC. The capillary containing the melted compound was set aside to cool, and resolidify. When the sample was retried, using the same capillary the sample melted at 133.6-154.5oC. Why is the melting point higher than 112°, and the range so wide?
According to the question, the determined melting point of the compound is 112.5-113.0oC. When the solidified compound was retried, the melting point was found to be 133.6-154.5oC. This greater range higher than 112°C is caused by reusing samples leads to errors.
A pure sample is known by its sharp melting point. A pure sample does not melt over a large range. We can see this in the predetermined melting points of the pure sample(112.5-113.0oC).
However, reusing a sample introduces errors because the pure sample may become contaminated leading to a larger and higher range of melting point (133.6-154.5oC) which is far above 112°C.
To find the acceleration, use the formula: force= mass x acceleration.
12.5 N = 10 x Acceleration
Acceleration = 12.5 / 10
Acceleration = 1.25
Hope this helps :)
