Question

substances a and b react in a ratio of a + b → ab. colin was combining substance a and substance b to form substance ab. he added 10 g of substance a and 45 g of substance b. how much of substance ab would colin make? 10 g 35 g 45 g 55 g

Explanation:

Step1: Identify the reaction ratio

The reaction is \( A + B
ightarrow AB \), meaning 1 mole (or gram, assuming equal molar masses for simplicity here) of A reacts with 1 gram of B to form AB. But we have 10 g of A and 45 g of B. So A is the limiting reactant (since 10 g A will react with 10 g B, leaving 35 g B unreacted).

Step2: Calculate mass of AB

Mass of AB = mass of A + mass of B that reacts = \( 10\,\text{g} + 10\,\text{g} = 20\,\text{g} \)? Wait, no, maybe I misread. Wait, maybe the ratio is 1:1 by mass? Wait, no, the law of conservation of mass: total mass of reactants is \( 10 + 45 = 55\,\text{g} \), but if A and B react completely? Wait, no, the reaction is A + B -> AB, so stoichiometric ratio 1:1. So if A is 10 g, B needed is 10 g. So AB formed is 10 + 10 = 20? But that's not an option. Wait, maybe the question is that A and B react in a 1:1 ratio, and we have 10 g A and 45 g B, so A is limiting, so AB is 10 + 10 = 20? But the options are 10,35,45,55. Oh! Wait, maybe I made a mistake. Maybe the reaction is that A and B react completely, so total mass of AB is mass of A + mass of B, but that would be 55 g. But that would be if both react completely. But the ratio is A + B -> AB, so if A is 10 g and B is 45 g, maybe B is in excess, but the reaction is 1:1, so A reacts with 10 g B, making 20 g AB, but that's not an option. Wait, the options include 55 g. Maybe the question is that A and B react completely, so total mass is conserved. So 10 + 45 = 55 g. So the answer is 55 g.

Answer:

55 g (the option with 55 g)