Limiting Reactant and Excess Reactant Calculations
Chemistry ⇒ Stoichiometry and Chemical Calculations
Limiting Reactant and Excess Reactant Calculations starts at 11 and continues till grade 12.
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A reaction requires 2 moles of A for every 3 moles of B. If you have 4 moles of A and 9 moles of B, which reactant is in excess?
Context: 10.0\,\mathrm{g} of Ca reacts with 10.0\,\mathrm{g} of O_2 to form CaO. Which is the limiting reactant? (Atomic masses: Ca = 40, O = 16)
Context: 2\mathrm{Na} + \mathrm{H}_2\mathrm{SO}_4 \rightarrow \mathrm{Na}_2\mathrm{SO}_4 + \mathrm{H}_2. If 4.6\,\mathrm{g} Na reacts with 9.8\,\mathrm{g} H_2SO_4, which is the limiting reactant? (Na = 23, H = 1, S = 32, O = 16)
Context: 5.0\,\mathrm{g} of Mg reacts with 10.0\,\mathrm{g} of HCl to form MgCl_2 and H_2. Which is the limiting reactant? (Mg = 24, H = 1, Cl = 35.5)
Context: 6.0\,\mathrm{g} of C_2H_6 reacts with 16.0\,\mathrm{g} of O_2 to form CO_2 and H_2O. Which is the limiting reactant? (C = 12, H = 1, O = 16)
Context: 7.0\,\mathrm{g} of N_2 reacts with 3.0\,\mathrm{g} of H_2 to form NH_3. What is the limiting reactant? (N = 14, H = 1)
Context: In the reaction 2\mathrm{Al} + 3\mathrm{Br}_2 \rightarrow 2\mathrm{AlBr}_3, if you have 13.5\,\mathrm{g} Al and 80.0\,\mathrm{g} Br_2, which is the limiting reactant? (Al = 27, Br = 80)
Context: In the reaction 2\mathrm{H}_2 + \mathrm{O}_2 \rightarrow 2\mathrm{H}_2\mathrm{O}, if you have 3.0\,\mathrm{mol} H_2 and 2.0\,\mathrm{mol} O_2, how many moles of water can be formed?
Context: In the reaction 2\mathrm{K} + \mathrm{Cl}_2 \rightarrow 2\mathrm{KCl}, if you have 10.0\,\mathrm{g} of K and 10.0\,\mathrm{g} of Cl_2, how many grams of KCl can be formed? (K = 39, Cl = 35.5)
Context: In the reaction 2\mathrm{SO}_2 + \mathrm{O}_2 \rightarrow 2\mathrm{SO}_3, if you have 8.0\,\mathrm{g} SO_2 and 4.0\,\mathrm{g} O_2, which is the limiting reactant? (S = 32, O = 16)
Define the term 'limiting reactant' in a chemical reaction.
Describe a real-world example where identifying the limiting reactant is important.
Describe how to calculate the amount of excess reactant remaining after a reaction.
Describe the process for determining the limiting reactant in a chemical reaction.
Explain why a reaction stops when the limiting reactant is used up.
Explain why it is important to identify the limiting reactant in a chemical reaction.
Explain why the limiting reactant is not always the reactant present in the smallest mass.
Given the reaction: \mathrm{N}_2 + 3\mathrm{H}_2 \rightarrow 2\mathrm{NH}_3. If you start with 5\,\mathrm{mol} N_2 and 12\,\mathrm{mol} H_2, which is the limiting reactant?
If 10.0\,\mathrm{g} of AgNO_3 reacts with 5.0\,\mathrm{g} of NaCl to form AgCl and NaNO_3, what mass of AgCl is formed? (Ag = 108, N = 14, O = 16, Na = 23, Cl = 35.5)
If 12.0\,\mathrm{g} of C reacts with 32.0\,\mathrm{g} of O_2 to form CO_2, what is the limiting reactant? (C = 12, O = 16)
