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Kabir drops 13 g of zinc into a solution that holds 7.3 g of hydrogen chloride: Zn + 2HCl → ZnCl₂ +…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
Kabir drops of zinc into a solution that holds of hydrogen chloride: . Which is the limiting reagent? Find the mass of hydrogen formed, its volume at STP, and the mass of zinc left over. Use , and .
Need a reminder? The key ideaShow
The coefficients of a balanced equation give the mole ratio. Mass to moles, moles by the mole ratio, then moles to mass. At STP one mole of a gas fills . The limiting reagent has the smallest moles divided by its coefficient; it is used up and fixes the product.
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. Moles. Zinc: . Hydrogen chloride: .
Step 2. Shares. Zinc: . Hydrogen chloride: . Hydrogen chloride is the limiting reagent.
Step 3. Hydrogen. , which is , and at STP.
Step 4. Zinc left. reacts, so is left: .
Answer: hydrogen chloride limits the reaction. It gives of hydrogen ( at STP), and of zinc is left.
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