Question

please help!!

2. When zinc metal reacts with copper(II) nitrate, zinc(II) nitrate and copper metal are the products. How many grams of zinc metal are required to react completely with 725 mL of 0.1955 M copper (II) nitrate solution? What mass of copper metal is produced? You will need a balanced equation to solve this problem! 3. One step in the process of manufacturing nitric acid (HNO3), a staple industrial chemical, is 3 NO2 (g) + H20 (1) ► 2HNO3 (aq) + NO (8) Starting with 1.55 kg NO2 and 0.355 kg of water, calculate the theoretical yield of nitric acid in grams. When the experiment is run, the actual yield of nitric acid is found to be 0.894 kg. What is the limiting reactant? What is the percent yield of the reaction?

Answer 1

2) Balanced chemical reaction;

Zn + Cu(NO3)2 -----> Cu + Zn(NO3)2

Moles of Cu(NO3)2 = Molarity * volume in liters = 0.1955 * (725/1000) = 0.14174 moles

From balanced reaction;

1 mole Cu(NO3)2 requires 1 mole Zn

So, 0.14174 moles will require = 1 * 0.14174 = 0.14174 moles of Zn

Mass of Zn = moles * molar mass = 0.14174 * 65.38 = 9.27 grams ....Answer

Again from reaction;

1 mole Cu(NO3)2 produces 1 mole Cu

So, 0.14174 mole will produce = 0.14174 moles of Cu

Mass of Cu = moles * molar mass = 0.14174 * 63.5 = 9.00 grams ....Answer

3)

3NO2 + H2O ---> 2HNO3 + NO

moles of NO2 = mass in grams/molar mass = 1.55*1000/46 = 33.696 moles

Moles of water = 0.355 * 1000/18 = 19.72 moles

From reaction;

1 mole H2O requires 3 moles NO2

So, 19.72 mole will require = 3*19.72 = 59.16 moles NO2

However available moles of NO2 = 33.696 which is less than the required one i.e. 59.16

Hence, NO2 is limiting reagent and it will drive the yield of product. And, H2O is excess reagent.

Again from reaction;

3 moles NO2 produces 2 moles HNO3

So, 33.696 mole NO2 will produce = 2*33.696/3 = 22.464 moles HNO3

So, mass of HNO3 produced (theoretical yield) = moles * molar mass = 22.464 * 63 = 1415.23 grams = 1.415 Kg ...Answer

% yield = 0.894 * 100 / 1.41523 = 63.17% ....Answer

Please note that answers may change slightly as molar mass may change slightly. Approach is 100%

Let me know if answer is not matching so that I can review the calculation part.