LIMITING and EXCESS REACTANT.S CHEMISTRYpptx

Chemistry

1. Limiting and Excess Reactant

2. What are reactants and products ? Let’s recall

3. Determine the limiting reactant in a reaction and calculate the amount of product formed (S11/12PS-IIIh-27) Learning competency

4. Learning objectives define limiting reactant and excess reactant in a chemical reaction determine the limiting reactant and excess reactant in a chemical reaction using moles 3. calculate the amount of product formed from the limiting reactant

5. “If you have 5 burger buns and 3 patties, how many complete burgers can you make?” Introduction Excess Limiting

6. Based from the example given, which of the following best defines limiting reactant and excess reactant? The limiting reactant is used up first, and the excess reactant is left over. The limiting reactant is the one with the most quantity, and the excess reactant is completely used. The limiting reactant is the one not used in the reaction, and the excess reactant is consumed completely. The limiting reactant is the one that makes the reaction go faster, and the excess reactant determines the amount of product. Limiting and Excess Reactant

7. Answer: The limiting reactant is used up first, and the excess reactant is left over. Limiting and Excess Reactant

8. Example: If you have 3 moles of H 2 and 2 moles of O 2, determine the limiting reactant and excess reactant. Step 1: Balance the chemical equation 2H 2 + O 2 H 2 O   Steps to determine limiting and excess reactant, and amount of product formed

9. Step 2: Using the molar ratios, convert both reactants to moles of H 2 O, then compare the results. The reactant that produces less amount of product is the limiting reactant and the remaining is the excess reactant . Steps to determine limiting and excess reactant, and amount of product formed

10. Step 2: We are given:3 moles of H₂; 2 moles of O₂ 3 moles H2 = 1.5 moles of H 2 2 2 moles O 2 = 2 moles of O 2 1 Steps to determine limiting and excess reactant, and amount of product formed

11. Example: In an experiment, suppose you have 4.5 g of Al and 2.25 g of NaCl are initially present, find: Al + NaCl  AlCl 3 + Na a. the limiting reactant? b. the excess reactant remains after the reaction? Steps to determine limiting and excess reactant, and amount of product formed

12. Step 1: Balance the chemical equation Al + 3 NaCl AlCl 3 + 3 Na   Steps to determine limiting and excess reactant, and amount of product formed

13. Step 2: Calculate the molar mass ( m.m ) of the reactants. m.m. Al = 27 g/mole m.m . NaCl = 58 g/mole Na = 1 x 23 = 23 g/mole Cl = 1 x 35 = 35 g/mole Steps to determine limiting and excess reactant, and amount of product formed

14. Step 3: Divide the calculated molar mass of the given element or compound from the given mass (conversion: g to mole). Then afterward, the number of moles are divided by the coefficient indicated in the balanced chemical equation. Steps to determine limiting and excess reactant, and amount of product formed

15. Al = 4.5 g = O.167 mol 27 g/moles NaCl = 2.25 g = 0.039 mol 58 g/mole Steps to determine limiting and excess reactant, and amount of product formed

16. For Al = 0 .167 mol = 0.167 mol 1 For NaCl = 2.25 g = 0.013 mol 3 Limiting Reactant  NaCl Steps to determine limiting and excess reactant, and amount of product formed

17. Your Turn!

18. Practice Activity Column 1 Reaction of 2 moles of CH 4 with 6 moles of O 2 CH 4 + O 2 CO 2 + H 2 O Column 2 Reaction of 5 moles of Cu with 3 mole of Cl 2 Cu + Cl 2 CuCl Column 3 Reaction of 4 moles of N 2 with 9 moles of H 2 N 2 + H 2 NH 3 Column 1 Column 2 Column 3

19. Practice Activity Answers Limiting reactant Excess reactant 1. CH 4 (2 mol) O 2 (3 mol) 2. Cu (5 mol) Cl 2 (6 mol) 3. H 2 (6 mol) N 2 (8 mol)

20. Application in daily living How can the limiting reactant concept be used in cooking to predict the amount of food that can be prepared from a given set of ingredients? Cooking does not involve limiting ingredients. All ingredients contribute equally, so the amount of food is unlimited The ingredient that runs out first determines how much food can be made. D. The ingredient with the largest quantity always determines the final amount.

21. Application in daily living How can the limiting reactant concept be used in cooking to predict the amount of food that can be prepared from a given set of ingredients? Cooking does not involve limiting ingredients. All ingredients contribute equally, so the amount of food is unlimited The ingredient that runs out first determines how much food can be made. D. The ingredient with the largest quantity always determines the final amount.

22. Assessment

23. Iyaman !