Multiple Choice
When 2.50 mol of Al and 3.00 mol of Cl2 combine in the reaction 2Al(s) + 3Cl2(g) → 2AlCl3(s), how many moles of the excess reactant remain at the end of the reaction?
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3. Chemical Reactions
Stoichiometry
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In the reaction between ammonia (NH_3) and phosphoric acid (H_3PO_4) to form ammonium phosphate ((NH_4)_3PO_4), how many moles of ammonia are required to react completely with 3 moles of phosphoric acid?
A
9 moles
B
6 moles
C
1 mole
D
3 moles
Verified step by step guidance1
Write the balanced chemical equation for the reaction between ammonia (NH_3) and phosphoric acid (H_3PO_4) to form ammonium phosphate ((NH_4)_3PO_4). The equation is: 3 NH_3 + H_3PO_4 \rightarrow (NH_4)_3PO_4.
Identify the mole ratio between ammonia and phosphoric acid from the balanced equation. Here, 3 moles of NH_3 react with 1 mole of H_3PO_4.
Use the given amount of phosphoric acid (3 moles) and apply the mole ratio to find the moles of ammonia required. Multiply 3 moles of H_3PO_4 by the ratio of NH_3 to H_3PO_4, which is 3:1.
Calculate the moles of ammonia needed by performing the multiplication: 3 moles H_3PO_4 \times 3 moles NH_3 / 1 mole H_3PO_4.
Interpret the result as the total moles of ammonia required to react completely with 3 moles of phosphoric acid.
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