A mixture of and weighing is treated with excess . Both metals dissolve and of is produced at STP. What is the mass of in the mixture?

Question

A mixture of  and  weighing  is treated with excess . Both metals dissolve and  of  is produced at STP. What is the mass of  in the mixture?

Canvas Classes · Accepted Answer

Strategy:
 This is a mixture problem where both components react to produce the same gaseous product. Set up two simultaneous equations: one for the total mass of the mixture and one for the total moles of Hydrogen gas produced.

Step 1: Calculate total moles of } \ce{H2}

Step 2: Set up equations
Let  and .
1) Mass: 
2)  Stoichiometry:  (Since  and )

Step 3: Solve for mass of Al
From (2), . Substitute into (1):

.

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