Classwork –Chemical Quantities (Stoichiometry)

  1. Using sandwich making as an analogy to chemical reactions, show the balanced equation that requires 2 pieces of bread, 3 slices of meat and on slice of cheese to make 1 sandwich.
  2. Using the ratios for the above process (reaction), show the balanced equation for making 25 sandwiches.
  3. Why are we able to multiply coefficients in a chemical equation?
  4. Why must we multiply each coefficient by the same amount?
  5. Explain why we must always balance a chemical equation.
  6. Define “one mole.”
  7. Show two ways to convey the balanced equation for the production of methanol from carbon monoxide hydrogen gases.
  8. Write a molecular level representation for the balanced equation showing water decompose to hydrogen and oxygen gases.
  9. Explain the term “mole ratio,” and give an example from an actual chemical equation.
  10. Write the balanced equation for the combustion of propane (C3H8) to form carbon dioxide and water.
  11. Show the mathematical set-up for determining the number of moles of oxygen required to react with 4.30 mole of propane.
  12. Calculate the moles of carbon dioxide and moles of water formed when 4.30 moles of propane reacts completely with oxygen.
  13. Write the balanced equation for the synthesis of ammonia (NH3) from nitrogen and hydrogen gases.
  14. Show the mathematical set-up for calculating the moles of ammonia that can be made from reacting 1.30 moles of hydrogen gas with excess nitrogen.
  15. Referring back to the balanced equation for the combustion of propane in question #10, show the 3-step mathematical expression “conversion string” for calculating the mass of oxygen gas required to react with 44.1 grams of propane. Explain what is taking place in each step.
  16. Write the balanced equation for the synthesis of aluminum iodide from aluminum metal and solid elemental iodine.
  17. Use the equation from #16 above to show the set-up and calculate the mass of iodine required to react with 35.0 grams of aluminum.
  18. Describe the term stoichiometry.
  19. Write the balanced equation for the neutralization of hydrochloric acid with sodium hydrogen carbonate (baking soda) and the balanced equation for the neutralization of hydrochloric acid with magnesium hydroxide (milk of magnesia).
  20. Show the set-up and calculations to confirm that magnesium is the better acid neutralizing substance.
  21. Sketch a molecular-level representation for the synthesis of ammonia from hydrogen and nitrogen gases using 9 molecules of hydrogen gas and 5 molecules of nitrogen gas, and show that the hydrogen gas is completely consumed (limiting reactant) while some nitrogen gas is left over (limiting reactant).
  22. Explain the concept of “limiting reactant.”
  23. Describe the terms “theoretical yield,” and “percent yield,” and show the mathematical expression for calculating percent yield.
  24. Which do we calculate using stoichiometry, the actual or the theoretical yield?