Midterm study guide

1. Why are all HVACR tradesmen advised to enroll in an approved first-aid course? **Quick and proper treatment of injuries can result in less pain and possibly save lives**
2. Safety protection should be worn: **At all times when performing any work that requires PPE.**
3. How can maintaining an orderly shop be beneficial? **Less time is wasted searching for required tools or materials.**
4. When should you read the SDS for a particular chemical product? **Before using the product**
5. How can you determine what PPE should be used with any particular chemical product? **Read the SDS form for that product**
6. When working with tools, a safety procedure to follow is to: **Always read the manufacturer's instructions**
7. Why should tools only be used for the jobs they were intended to perform? **They have not been tested for safety for jobs they were not designed for.**
8. Before changing the blade in an electric circular saw, you should: **Unplug the saw**
9. The base of an extension ladder that is correctly set up will be: **1 foot from the wall for every 4 feet in length.**
10. The top of an extension ladder: **Should extend at least 36 inches above the point where it rests on the building.**
11. How can a confined space, such as a walk-in cooler or underground tunnel, become a safety hazard? **The oxygen is limited—long exposure can cause suffocation**
12. Match the fire extinguisher class with the type of fire. Combustible metals:**Class D** Flammable liquids:**Class B** Ordinary combustibles: **Class A** Electrical fires: **Class C**
13. Why should oil or grease never be used to lubricate oxygen or acetylene regulators? **It can react with certain chemicals or materials and result in an explosion.**
14. Why might a bad driving record make it difficult to get a job at a service company? **Your driving record affects the cost of insurance to the company.**
15. In case of an accident, the first step is: **Call 911.**
16. Which types of accidents should be reported? **All accidents**
17. What is a service valve wrench? **A ratchet wrench with square openings that fit service valve stems**
18. What are the most common sizes of standard sockets? **From 1/4 in up to 1 in in 1/16-in increments**
19. What is the difference between a flare-nut wrench and a standard box wrench? **The flare wrench heads are slotted to slip over the tubing.**
20. Why are mushroomed chisel heads dangerous? **Chips may break off.**
21. What should be done with damaged tools? **Throw them away.**
22. Why should pliers NOT be used to tighten bolts and nuts? **They will round off the corners.**
23. A barometer is used to read:**Atmospheric pressure.**
24. Define a vacuum. **A vacuum is any pressure less than atmospheric pressure**
25. The specific gravity of water is: **1.0**
26. When gas exerts pressure on its container, the pressure is: **Distributed equally on all surfaces of the container.**
27. Atmospheric pressure is created by: **The weight of the air in the atmosphere**
28. The first law of thermodynamics states that: **Energy cannot be created or destroyed**
29. The absolute temperature scale for Fahrenheit is: **Rankine**
30. Convert 40° Celsius to Fahrenheit. **40 × 1.8 = 72; 72 + 32 = 104°F**
31. Atmospheric pressure is affected by: **Altitude, temperature, and humidity.**
32. According to Pascal's law, what happens to the pressure of a propane tank as it empties? **The pressure remains uniform throughout the tank.**
33. Convert 40° Fahrenheit to Celsius. **40 - 32 = 8; 8/1.8 = 4.4°C**
34. It is important to the HVACR technician to understand the changes of state of matter because: **The cooling and heating process requires a change of state of matter in some form.**
35. The three basic methods of heat transfer are: **Conduction, convection, and radiation.**
36. What is absolute zero? **The coldest temperature possible where all molecular motion stops**
37. The total pressure in a mixture of gases is equal to: **The sum of all the individual gas partial pressures.**
38. According to the second law of thermodynamics, how does heat travel? **Heat energy travels from a warmer body to a cooler body.**
39. What is the relationship between atoms and molecules? **Molecules are made up of atoms.**
40. The law of conservation of matter states that: Matter cannot be created or destroyed.
41. The nucleus of an atom: **Is composed of protons and neutrons.**
42. The curved oval metal tube inside a gauge is called: **A Bourdon tube.**
43. A thorough knowledge of the properties of matter is necessary to: **Better understand what happens to various forms of matter and the reasons why changes occur when substances are heated or cooled.**
44. The absolute temperature scale for Celsius is: **Kelvin**
45. The definition of sublimation is: **A substance in a solid state changes into the gaseous state without going through the liquid state.**
46. Matter cannot be created or destroyed, but it can and does change form. This statement is known as: **The law of conservation of matter**.
47. Standard atmospheric pressure at sea level with a temperature of 59°F is: **14.7 psia or 29.92 in Hg.**

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