Practice Test Geeks(CAR) Certified Appliance Recycler Practice Test
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Material Selection & Properties Flashcards

7 cards from real CAR practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Material Selection & Properties flashcards as text

  1. What is the significance of a material's Curie temperature in appliance recycling metal sorting?

    Answer: Above this temperature, ferromagnetic metals lose their magnetic properties

    Understanding the Curie temperature is important because magnetic separation efficiency changes if materials are heated during processing.

  2. Which refrigerant oil type requires separate collection because it is miscible with HFC refrigerants?

    Answer: Polyolester (POE) oil

    POE oil is used with HFC refrigerants like R-134a and must be properly drained and managed due to its hygroscopic nature and environmental concerns.

  3. Acrylonitrile butadiene styrene (ABS) plastic in appliance housings is best identified by which characteristic?

    Answer: It sinks in water and has resin code #7 or #9

    ABS has a density greater than water (~1.05 g/cm³) and is typically coded #7 (other) or #9 on the resin identification system.

  4. Lead solder used in older appliance circuit boards is hazardous primarily due to its:

    Answer: Toxicity and classification as a RCRA hazardous waste

    Lead is classified as a hazardous substance under RCRA, and circuit boards with lead solder must be managed accordingly to prevent soil and groundwater contamination.

  5. What property makes aluminum an energy-efficient choice for heat exchanger fins in air conditioners?

    Answer: High thermal conductivity combined with low density

    Aluminum's high thermal conductivity (~205 W/m·K) and low density make it ideal for fins that must efficiently transfer heat while minimizing weight.

  6. In appliance recycling, 'zorba' refers to:

    Answer: A mixture of shredded non-ferrous metals after steel removal

    Zorba is the industry term for a mixed non-ferrous metal fraction (mainly aluminum with copper, zinc, and other metals) produced after magnetic and ferrous removal.

  7. Which material property determines whether a plastic component will sink or float during density-based separation in recycling?

    Answer: Specific gravity relative to the separation medium

    Sink-float separation exploits differences in specific gravity: plastics denser than the medium sink, while less dense plastics float for sorting.