a heating curve for two unknown substances is shown. which statement is valid? a substance x has the same…

a heating curve for two unknown substances is shown. which statement is valid? a substance x has the same melting point and boiling point as substance y. b substance x has a higher melting point and boiling point than substance y. c substance x has a lower melting point and boiling point than substance y. d substance x has a lower melting point and higher boiling point than substance y.

a heating curve for two unknown substances is shown. which statement is valid? a substance x has the same melting point and boiling point as substance y. b substance x has a higher melting point and boiling point than substance y. c substance x has a lower melting point and boiling point than substance y. d substance x has a lower melting point and higher boiling point than substance y.

Answer

Brief Explanations:

  • On a heating curve, the flat - regions represent phase changes. The first flat - region is the melting point (solid - to - liquid phase change) and the second flat - region is the boiling point (liquid - to - gas phase change).
  • For Substance X, the first flat - region (melting point) is at a higher temperature than the first flat - region of Substance Y. Also, the second flat - region (boiling point) of Substance X is at a higher temperature than the second flat - region of Substance Y.

Answer:

B. Substance X has a higher melting point and boiling point than Substance Y.