The published reference melting point range for aspirin is 134 °C to 136 °C. Your measured melting point range was lower than this.

Which of the following might be reasonable explanations for the difference? Which of the following statements are true?

A. Incorrect sample preparation can lead to discrepancies. Inadequate grinding or uneven packing of the sample can affect the observed melting point.

B. Presence of impurities in the sample can alter the melting point. Contaminants may depress or elevate the observed melting point, causing it to deviate from the expected range.

C. If the sample is not thoroughly dried, the presence of solvent molecules can significantly alter the melting point.

D. Isotopes play a role. Suppose the material contains isotopically enriched atoms. Isotopic effects can significantly shift the melting point.

E. The rate at which the sample is heated influences the melting point. Rapid heating may cause the material to melt at a slightly different temperature than expected.