Melting Point

The melting point of a substance is_____

• the temperature at which the solid starts to melt

• the temperature at which all of the solid has melted

• the temperature range over which the solid first starts to melt, to when all of the solid has melted

• the temperature at which the solid starts to melt, rounded to the nearest whole number

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

NGSS.MS-PS3-5

Melting point analysis can be used to_____. Tick all that apply.

• purify a compound

• give an indication of the purity of a compound

• confirm the identity of a pure compound

• identify the impurities present in the sample

The presence of impurities in the compound ____ the melting point and ____its melting temperature range

• lowers; broadens

• lowers; narrows

• increases; broadens

• increases; narrows

Mixing a small quantity of the product with some of the pure compound and determining the MP and the range of the melting temperature to determine if the product and the pure compound are the same substance is called___

• mixed melting point

• pure melting point

• mixed melting range

• double melting point

Why is the melting temperature range different for a compound with and without impurities?

• due to disruption in intermolecular bonding in the crystal lattice

• due to disruption in intramolecular bonding in the crystal lattice

• due to broken covalent bonds

• due to new covalent bonds being made

Tags

NGSS.HS-PS3-4