Composition of Air
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Questions and Answers

What percentage of the air at sea level is comprised of oxygen?

  • 78.09%
  • 0.03%
  • 0.94%
  • 20.94% (correct)

    • Which of the following gases is NOT typically found in pure, dry air at sea level?

  • Helium
  • Nitrogen
  • Methane (correct)
  • Hydrogen

    • What is the primary mechanism by which gases can affect humans in a mine?

  • Toxic properties
  • Combustible properties
  • Displacement of oxygen (correct)
  • Explosive properties

    • What is a potential source of methane in a mine?

    <p>Diffusion from ore or country rock (D)</p> Signup and view all the answers

    What is the primary purpose of adequate positive ventilating currents in a mine?

    <p>To prevent the accumulation of hazardous gases (A)</p> Signup and view all the answers

    What is the minimum percentage of oxygen required in the atmosphere at the workplace?

    <p>19.5% (A)</p> Signup and view all the answers

    What is the explosive range of propane?

    <p>2.4%–9.5% (B)</p> Signup and view all the answers

    At what percentage of oxygen in the atmosphere can a person experience dizziness, buzzing noise, and rapid pulse?

    <p>15% (A)</p> Signup and view all the answers

    What is the chemical symbol for propane?

    <p>C₃H₈ (D)</p> Signup and view all the answers

    What happens to the heart shortly after breathing stops due to oxygen deficiency?

    <p>It stops (A)</p> Signup and view all the answers

    What unit is used to measure airborne particulate concentrations?

    <p>Milligrams per cubic metre of air (C)</p> Signup and view all the answers

    What is the standard substance used for measuring relative density of gases?

    <p>Air (C)</p> Signup and view all the answers

    What is the term for the minimum concentration of a gas or vapour in air that will ignite when exposed to an ignition source?

    <p>Lower Explosive Limit (A)</p> Signup and view all the answers

    What is the pH of pure water?

    <p>7 (D)</p> Signup and view all the answers

    What property of air allows it to be compressed to a liquid or frozen to a solid?

    <p>Weight (B)</p> Signup and view all the answers

    What happens when nitric oxide (NO) is exposed to air?

    <p>Nitrogen dioxide (NO₂) is formed (B)</p> Signup and view all the answers

    What is the minimum exposure level of nitrogen dioxide that can cause immediate throat irritation?

    <p>60 PPM (B)</p> Signup and view all the answers

    What is the effect of nitrogen on humans?

    <p>It has no physiological effect (D)</p> Signup and view all the answers

    What is the colour of nitrogen dioxide in high concentrations?

    <p>Reddish brown (D)</p> Signup and view all the answers

    What is the effect of inhaling nitrogen dioxide in high concentrations?

    <p>It causes bronchitis or pneumonia (C)</p> Signup and view all the answers

    What is the primary effect of inhaling high concentrations of MAPP?

    <p>Anesthesia-like effect (B)</p> Signup and view all the answers

    What is the minimum percentage of methane required to isolate electrical circuits in a work environment?

    <p>1.25% (B)</p> Signup and view all the answers

    What is a common characteristic shared by MAPP, methane, and nitrogen?

    <p>Colourless and odourless (B)</p> Signup and view all the answers

    What is a possible source of methane gas?

    <p>Diamond drilling operations (C)</p> Signup and view all the answers

    What is a potential hazard of skin contact with liquid MAPP?

    <p>Tissue freezing or frostbite (B)</p> Signup and view all the answers

    Which gas is formed through the decomposition of organic matter, carbonaceous rock, decaying timber, and is a component of natural gas?

    <p>Methane (C)</p> Signup and view all the answers

    Which gas has a characteristic 'bitter almond' odour?

    <p>Hydrogen Cyanide (D)</p> Signup and view all the answers

    Which gas is heavier than air and has a characteristic 'rotten egg' odour?

    <p>Hydrogen Sulphide (A)</p> Signup and view all the answers

    Which gas is formed through the reaction of nitrogen and hydrogen in the presence of a catalyst?

    <p>Ammonia (C)</p> Signup and view all the answers

    Which gas is a constituent of air, but can be formed through the decomposition of some sulphur compounds, blasting sulphide ores, and decomposition of vegetable matter in water?

    <p>Hydrogen Sulphide (D)</p> Signup and view all the answers

    What is the primary source of hydrogen gas at mines?

    <p>Battery charging (B)</p> Signup and view all the answers

    What is the explosive range of hydrogen gas?

    <p>4%–75% with 5% oxygen (D)</p> Signup and view all the answers

    What is the characteristic of hydrogen cyanide gas?

    <p>Colourless, with a distinctive odour of bitter almonds (C)</p> Signup and view all the answers

    What is the effect of hydrogen gas on humans?

    <p>It causes asphyxiation due to an oxygen-deficient atmosphere (D)</p> Signup and view all the answers

    What should be done to stop a pinhole leak in a chlorine gas cylinder?

    <p>Drive a tapered hardwood peg or metal drift pin into the hole (D)</p> Signup and view all the answers

    What is the effect of chlorine gas on humans at a concentration of 16–30 PPM?

    <p>Chest pain, vomiting, coughing, and difficulty breathing (D)</p> Signup and view all the answers

    What is the chemical symbol for chlorine gas?

    <p>Cl₂ (C)</p> Signup and view all the answers

    What is the purpose of turning a chlorine gas cylinder so that only gas is escaping before plugging the leak?

    <p>To make it easier to drive the plug into the hole (D)</p> Signup and view all the answers

    What should be done after temporarily stopping a pinhole leak in a chlorine gas cylinder?

    <p>Empty the cylinder as quickly as possible (D)</p> Signup and view all the answers

    What is the effect of chlorine gas on humans at a concentration of 0–6 PPM?

    <p>Eye irritation (A)</p> Signup and view all the answers

    What is the primary factor that affects the strength of clear blue lake-ice?

    <p>The movement of water beneath the ice (C)</p> Signup and view all the answers

    What should be done to determine the strength of the ice before traveling on it?

    <p>Test the thickness of the ice frequently in various locations (B)</p> Signup and view all the answers

    What type of ice is the strongest form of ice?

    <p>Clear or natural ice (C)</p> Signup and view all the answers

    What happens when a vehicle travels on ice?

    <p>It creates a resonance wave in the underlying water (A)</p> Signup and view all the answers

    What percentage should loads be reduced by when traveling on clear blue river-ice?

    <p>15% (D)</p> Signup and view all the answers

    What is the maximum allowable mass of a vehicle in motion for an ice thickness of 20 cm?

    <p>10,000 kg (C)</p> Signup and view all the answers

    What is the primary concern when driving a vehicle on ice roads?

    <p>The weight and speed of the vehicle affecting the size and speed of the wave (B)</p> Signup and view all the answers

    What is the speed limit for an empty vehicle on ice roads?

    <p>35 km/h (D)</p> Signup and view all the answers

    What is the potential consequence of the resonance wave on the ice?

    <p>The ice will be more likely to fail (B)</p> Signup and view all the answers

    What is the formula used to determine the maximum allowable mass of a vehicle on ice?

    <p>M = 4 × h2 (A)</p> Signup and view all the answers

    What is the primary area of heat loss from the body?

    <p>Head and neck (B)</p> Signup and view all the answers

    What is the purpose of the H.E.L.P. technique?

    <p>To reduce heat loss from the body (B)</p> Signup and view all the answers

    What happens to the heart rate and respiration rate as hypothermia progresses?

    <p>They decrease rapidly (D)</p> Signup and view all the answers

    What is a critical consideration when conserving body heat?

    <p>Protecting the head and neck (B)</p> Signup and view all the answers

    What is the eventual outcome if hypothermia is left untreated?

    <p>All of the above (D)</p> Signup and view all the answers

    What is the primary factor that affects the strength of clear blue lake-ice?

    <p>Temperature (C)</p> Signup and view all the answers

    What should be done to determine the strength of the ice before traveling on it?

    <p>Drill a hole to check the thickness (A)</p> Signup and view all the answers

    What happens when a vehicle travels on ice?

    <p>The ice is more likely to crack or break (C)</p> Signup and view all the answers

    What is the term for the minimum concentration of a gas or vapour in air that will ignite when exposed to an ignition source?

    <p>Flammable range (C)</p> Signup and view all the answers

    What type of ice is the strongest form of ice?

    <p>Clear blue lake-ice (B)</p> Signup and view all the answers

    What is the expected survival time if a person is exposed to water with a temperature between 0°C and 5°C?

    <p>15–30 minutes (A)</p> Signup and view all the answers

    At what water temperature range is exhaustion or unconsciousness expected to occur in less than 15 minutes?

    <p>0°C (C)</p> Signup and view all the answers

    What is a characteristic of someone experiencing moderate hypothermia?

    <p>Mild confusion and stumbling pace (C)</p> Signup and view all the answers

    What is the minimum core temperature range for someone to be classified as having mild hypothermia?

    <p>36.1–35.0°C (D)</p> Signup and view all the answers

    What is a common symptom of someone experiencing severe hypothermia?

    <p>Sluggish thinking and amnesia (B)</p> Signup and view all the answers

    What is a primary factor that contributes to the development of hypothermia?

    <p>All of the above (D)</p> Signup and view all the answers

    What is a common characteristic of people who fail to recognize symptoms of hypothermia?

    <p>They are people who die in the outdoors (D)</p> Signup and view all the answers

    What is the result when the body loses heat faster than it can produce it?

    <p>Hypothermia (D)</p> Signup and view all the answers

    What are some of the visible symptoms that indicate the onset of hypothermia?

    <p>Shivering, confusion, and drowsiness (A)</p> Signup and view all the answers

    What happens when the body is exposed to cold, wind, or water?

    <p>Heat loss increases (A)</p> Signup and view all the answers

    What is the primary hazard associated with oxygen deficiency during a mine fire?

    <p>Oxygen replacement by toxic or inert gases (A)</p> Signup and view all the answers

    Which gas is always present during a mine fire and gives little or no warning of its presence?

    <p>Carbon monoxide (D)</p> Signup and view all the answers

    What is the primary effect of sulphur dioxide gas during a mine fire?

    <p>It gives advance warning in low concentrations (B)</p> Signup and view all the answers

    Which gas is not produced by mine fires or explosions but may cause them?

    <p>Methane (B)</p> Signup and view all the answers

    What is the primary hazard associated with methane gas in a mine?

    <p>It is a major hazard during rescue or recovery operations (D)</p> Signup and view all the answers

    What is the primary concern during and after mine fires?

    <p>Carbon monoxide poisoning and oxygen deficiency (C)</p> Signup and view all the answers

    What is the primary characteristic of hydrogen sulphide gas?

    <p>It sometimes indicates the presence of methane (C)</p> Signup and view all the answers

    Which gas is formed through the reaction of nitrogen and hydrogen in the presence of a catalyst?

    <p>Ammonia (C)</p> Signup and view all the answers

    What is the primary factor that affects the strength of clear blue lake-ice?

    <p>Temperature (B)</p> Signup and view all the answers

    What is the primary mechanism by which gases can affect humans in a mine?

    <p>Oxygen replacement by toxic or inert gases (C)</p> Signup and view all the answers

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