9 grade science> WHAT ARE THE FACTORS AFFECTING MELTING PO...

WHAT ARE THE FACTORS AFFECTING MELTING POINT

A M S ARUN KRISHNA , 9 Years ago

Grade 9

2 Answers

Abishek arun

Last Activity: 9 Years ago

factors affecting melting point

effect of pressure
addition of impurities

Approved

deapan

Last Activity: 9 Years ago

FACTORS AFFECTING MELTING POINT

EFFECT OF CHANGE OF PRESSURE

The effect of pressure on the melting point of solid depends upon the nature of solid

For solids which expand on melting, increase in pressure increases the melting point. This is because increase in melting point opposes expansion. Examples: paraffin wax, silver, gold, copper. For solids which contract on melting, increase in pressure decreases the melting point. Examples: ice, cast iron, brass

Ice is a solid which contracts on melting, its melting point decreases. When two ice cubes are pressed together, the ice at interface melts due to the application of slight pressure. When pressure is released it solidifies again thereby joining the two ice cubes. This principle is called regelation.

ii)EFFECT OF ADDITION OF IMPURITIES

Addition of impurities to a solid decreases the melting point of solid

Example: Rose metal – allow of tin, lead and bismuth