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    Cards (101)

    • Molar gas volume
      Volume a mole of gas occupies measured in decimeters cubed per mole
    • Gases occupy the same volume of space under the same conditions
    • Mole or gas calculations
      Number of moles = Volume (in decimeter cubed) / Molar gas volume
    • The video is a revision video for OCR piece alters presented by Chris Harris from alarrytutors.com
    • At standard room temperature and pressure, 1 mole of any gas occupies 24 decimeters cubed per mole
    • The ideal gas equation can take into account differing temperatures and pressures
    • Ideal gas equation
      PV = NRT
    • Volume of a gas can be found experimentally by collecting it through a gas syringe or using an upturned measuring cylinder in a tank of water
    • Gas volumes calculation using molar and volume calculations
      Moles = Mass / Relative atomic mass
    • Unit conversion from meters to decimeters, decimeters to centimeters
      Multiply by 10 for each conversion
    • Converting pressure from kPa to Pa
      Multiply by 1000
    • When using the ideal gas equation, ensure to use the units provided and be able to rearrange the equation
    • Unit conversion from meters² to centimeters²
      Multiply by 10,000
    • Calculating volume of a gas using ideal gas equation
      Given values: N = 0.36 moles, R = 8.31, T = 298K, P = 100 kPa
    • Converting volume from m³ to cm³
      Multiply by 1,000,000
    • Gas constant R is 8.31, standard conditions are 298K and 101.3 kPa
    • Unit conversion from meters³ to centimeters³
      Multiply by 1,000
    • For meters³ to centimeters³ conversion, multiplying by a million is required for each additional dimension
    • When converting volumes in chemistry, add an extra zero for each additional dimension
    • For meters³ to centimeters³ conversion, multiply by 1,000 for each dimension
    • Calculating volume of gas produced in a reaction
      Given values: 12g of potassium, 100 kPa pressure, 298K temperature, gas constant 8.31 J/(K*mol)
    • Calculating moles of hydrogen produced
      Using stoichiometry from balanced equation
    • Calculating moles of potassium
      Number of moles = mass / atomic mass
    • Using ideal gas equation to calculate volume of gas
      Volume = (0.1115 * 8.31 * 298) / 100,000
    • Volumes of gases produced in reactions can be measured using a gas syringe
    • Measuring the volume of a gas
      Volumes of gases produced in a reaction can be measured using a gas syringe
    • Standard state
      The substance is under standard conditions of 100 kilopascals and 298 Kelvin (25 degrees Celsius)
    • For reactions producing a larger volume of gas in a short space of time, precautions need to be taken to prevent accidents
    • Gas syringe measures the amount of gas produced in a reaction
    • When the plunger doesn't move any further, the reaction has stopped and that volume can be measured
    • Reactions can either give out heat energy (exothermic) or absorb heat energy (endothermic)
    • Enthalpy change (ΔH)
      The heat change in a reaction at a constant pressure, symbolized by ΔH in kilojoules per mole
    • Enthalpy change is a change in energy during a chemical reaction
    • Preliminary experiments may be needed to adjust reactants or equipment if the gas produced is more than expected
    • Endothermic reactions absorb energy from the surroundings, while exothermic reactions release energy to the surroundings
    • Bond breaking is an endothermic process as energy is absorbed when bonds are broken
    • Bond making is an exothermic process as energy is released when bonds are formed
    • If more energy is released when bonds are formed than needed to break them, the overall reaction is exothermic
    • Bond enthalpy is the amount of energy needed to break one mole of a bond type in a molecule in the gaseous state
    • Bond enthalpy
      The amount of energy needed to break one mole of a bond type in a molecule in the gaseous state
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