Consider the equation: 5A+2Barrow C+D You react 7 moles of A with 4 moles of B. Which of the following is true: A is the limiting reactant because you need 10 and you have 7 B is the limiting reactant because 7 A molecules react with 4 B molecules B is the limiting reactant because you have fewer moles of B than A A is the limiting reactant because of its lower molar mass

To determine the limiting reactant, we need to compare the amount of each reactant available to the amount required by the balanced chemical equation.<br /><br />Given the balanced chemical equation: $5A + 2B \rightarrow C + D$<br /><br />We are given that 7 moles of A and 4 moles of B are reacted.<br /><br />To find the limiting reactant, we need to calculate the amount of product that can be formed from each reactant.<br /><br />For A:<br />The balanced equation shows that 5 moles of A are required to produce 1 mole of product. Therefore, with 7 moles of A, we can produce $\frac{7}{5} = 1.4$ moles of product.<br /><br />For B:<br />The balanced equation shows that 2 moles of B are required to produce 1 mole of product. Therefore, with 4 moles of B, we can produce $\frac{4}{2} = 2$ moles of product.<br /><br />Comparing the amounts of product that can be formed from each reactant, we see that A produces fewer moles of product than B. Therefore, A is the limiting reactant.<br /><br />So, the correct answer is: A is the limiting reactant because you need 10 and you have 7.