A Substance Has a Melting Point of 20°C and a Heat

question 189

Multiple Choice

A substance has a melting point of 20°C and a heat of fusion of $3.6 \times 10 ^ { 4 } \mathrm {~J} / \mathrm { kg }$ The boiling point is $150 ^ { \circ } \mathrm { C }$ and the heat of vaporization is $7.2 \times 10 ^ { 4 } \mathrm {~J} / \mathrm { kg }$ at a pressure of one atmosphere. The specific heats for the solid, liquid, and gaseous phases are 600 J/kg ? K (solid) , 1000 J/kg ? K (liquid) , and 400 J/kg ? K (gaseous) . How much heat is given up by $2.80 \mathrm {~kg}$ of this substance when it is cooled from 170°C to 86°C at a pressure of one atmosphere?

• A)400 kJ
• B)200 kJ
• C)300 kJ
• D)440 kJ
• E)640 kJ

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Definitions:

Procedural Memory

A type of long-term memory involved in the learning of skills and tasks that can be performed without conscious thought.

Echoes

Repetitive sounds that are heard after the original sound has been made, typically as a result of the reflection of sound waves.

Limbic System

A complex system of nerves and networks in the brain, involved with instinct and mood, controlling basic emotions and drives.

Engram

An assumed electrical circuit in the brain that corresponds to a memory trace.