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Substance AB2 is 60.0% A by mass. What is the percent A by mass for substance AB?

User Mbask
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Answer

The percent of A by mass for substance AB is 75%

Explanation:


\begin{gathered} Prosut\text{ states }the\text{ Comparative law that compounds }are\text{ formed from }elements\text{ }with\text{ the same }mass\text{ comparison, } \\ so\text{ that compounds have a fixed }composition\text{ of }elements. \\ _{} \\ \text{ From substance AB}_2\text{ }is\text{ 60\% by mass of A} \\ \text{ Assume }thatAB_{2\text{ }}\text{ = 100 grams} \\ \text{ A + B = AB}_2 \\ A\text{ + B = 100} \\ A\text{ = 60 grams} \\ B\text{ = 100 - A} \\ B\text{ =100 - 60} \\ B\text{ = 40 grams} \\ \text{ The coefficient of AB}_2\text{ = 2} \\ Then,\text{ B = 40/2 = 20 grams} \\ In\text{ compound AB} \\ AB\text{ = A + B} \\ AB\text{ = 60 + 20} \\ AB\text{ = 80 grams} \\ \text{The percentage of A in AB is (60:80)} \\ \text{ \%A = }(60)/(80)\text{ x 100\%} \\ \text{ \%A = 75\%} \end{gathered}

User PMa
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