Phase Changes: a Substance Has a Melting Point of 20°C

question 82

Multiple Choice

Phase changes: A substance has a melting point of 20°C and a heat of fusion of 3.5 × 10⁴ J/kg. The boiling point is 150°C and the heat of vaporization is 7.0 × 10⁴ J/kg at a pressure of 1.0 atm. The specific heats for the solid, liquid, and gaseous phases are 600 J/(kg ∙ K) , 1000 J/(kg ∙ K) , and 400 J/(kg ∙ K) , respectively. The quantity of heat given up by 0.50 kg of the substance when it is cooled from 170°C to 88°C, at a pressure of 1.0 atmosphere, is closest to

• A) 70 kJ.
• B) 14 kJ.
• C) 21 kJ.
• D) 30 kJ.
• E) 44 kJ.

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Definitions:

Direct Method

A cash flow statement preparation approach that lists major classes of gross cash receipts and payments.

Operating Activities

Business activities related directly to the production and delivery of goods and services, generating revenue and cash flow.

Indirect Method

A technique used in cash flow statement preparation that adjusts net income for changes in non-cash accounts to compute cash flow from operating activities.

Operating Activities

Activities that relate to the core business operations of a company, including production, sales, and day-to-day administration.