When sending copper metal through a cycle of reactions, it is most important to have an idea how much of any given reagent is needed to bring each step of the cycle of reactions to completion. In order to assure a complete reaction, reagents are often added in excess (up to 10 fold), but too much as well as too little might hamper the course of a reaction. The five key steps of the copper cycle are shown below:
Step 1: 3 Cu(s) + 2NO3- + 8H+ 4 3 Cu2+(aq) + 4 H2O + 2 NO Step 2: Cu2+(aq) + 2 OH-(aq) - Cu(OH)2(s)
Step 3: Cu(OH)2(s) 4 CuO(s)+ H2O
Step 4: CuO(s) + 2 H+ 4 Cu2+(aq) + H2O
Step 5: Cu2+(aq) + Zn(s) 4 Zn2+(aq) + Cu(s)
Assume that you want to carry out a sequence of cycle reactions based on 1.00 g of copper. In order to use the right amount of reagents,
present answers to the following questions:
1. What volume of 16 M HNO3 is required to completely react with Cu in the first step of the cycle?
2. What volume of 3.0 M NaOH is required to precipitate all copper(II) cations as Cu(OH)2 in the second step of the cycle?
3. How many grams of copper(II)oxide will form when the third step of the cycle goes to completion?
4. What volume of 6. M H2SO4 is required to completely convert all copper(II)oxide to copper(II) cation in the fourth step of the cycle?
5. How many grams of zinc metal are needed to completely regenerate all copper in the fifth step in the cycle?