Energetics Term 1 Test 2.0

• What is an exothermic reaction?


  Heat is given out to the surroundings.
• What is the effect of an exothermic reaction on temperature?


  It causes an increase in temperature.
• What is an example of an exothermic reaction?


  Combustion.
• What is an endothermic reaction?


  Heat is taken in from the surroundings.
• What is the effect of an endothermic reaction on temperature?


  It causes a decrease in temperature.
• What is an example of an endothermic reaction?


  Decomposition.
• What is the process of combustion?


  Burning a substance and measuring heat.
• What is the formula for heat energy change (q)?


  q = m × c × ΔT
• What does 'm' represent in the heat energy change formula?


  Mass of water (grams).
• What does 'c' represent in the heat energy change formula?


  Heat capacity (e.g., 4.18).
• What does 'ΔT' represent in the heat energy change formula?


  Change in temperature.
• What is the formula for molar enthalpy change?


  ΔH = q / n
• What does 'ΔH' represent in the molar enthalpy change formula?


  Heat energy change.
• What does 'n' represent in the molar enthalpy change formula?


  Number of moles.
• Can salts dissolving be exothermic or endothermic?


  Yes, they can be either exothermic or endothermic.
• What type of reaction is a neutralization reaction?


  Exothermic, releasing heat.
• What is RFM (Relative Formula Mass)?


  Sum of all RAM of the compound.
• What does RAM stand for?


  Relative Atomic Mass.
• What is the definition of a mole?


  Amount of substance.
• How many particles are in one mole? 6.02x 10²³ (Avogadro’s number).
• How is the mass of one mole related to RFM?


  1 mole = RFM (Mr) in grams.
• What is the formula for the amount of substance?

  n = m / Mr
• How many moles are in 10 g of NaCl (Mr = 58.5)?


  n = 10 g / 58.5 = 0.171 moles.
• What are the steps for reacting mass calculations?


  1. Write the balanced chemical equation.
  2. Use the mole ratio to find the ratio of reactants to products.
  3. Calculate the moles of the known substance using its mass and Mr.
  4. Use the mole ratio to determine the moles of the unknown substance.
  5. Calculate the mass of the unknown substance using its Mr and the moles calculated.
• In the reaction \( H_2 + Cl_2 \rightarrow 2HCl \), if you have 2g of H₂, how do you calculate the mass of HCl produced?


  Use the balanced equation and mole ratios.
• What is the formula for percentage yield?


  \text{Percentage yield} = \frac{\text{Actual yield}}{\text{Theoretical yield}} \times 100
• What is the actual yield?


  The amount of product obtained.
• What is the theoretical yield?


  The maximum possible amount of product based on the reactants.
• What are the key points of reacting mass calculations?


  • Write the balanced chemical equation.
  • Use the mole ratio to find the ratio of reactants to products.
  • Calculate the moles of the known substance using its mass and Mr.
  • Use the mole ratio to determine the moles of the unknown substance.
  • Calculate the mass of the unknown substance using its Mr and the moles calculated.
• What are the key components of percentage yield?


  • Actual yield: Amount of product obtained.
  • Theoretical yield: Maximum possible amount of product based on reactants.
  • Formula: \text{Percentage yield} = \frac{\text{Actual yield}}{\text{Theoretical yield}} \times 100