1. Nickel, a common metal used in a variety of alloys, is purified via the Mond

Question

1. Nickel, a common metal used in a variety of alloys, is purified via the Mond process to a very high (> 99.99%) purity. One of the steps in the Mond process involves the reaction of solid nickel with carbon monoxide to produce Ni(CO)4, as shown in the unbalanced equation below.

Ni(s) + CO(g) Ni(CO)4(g)

How much carbon monoxide, in grams, is required to purify an impure sample containing 4.22 kg of nickel? (to the correct number of sig figs please)

2. Phosphorus pentachloride is a solid that reacts with water to form phosphoric acid and hydrogen chloride gas. The reaction can be represented by the following chemical equation.

PCl5(s) + 4 H2O(l) H3PO4(l) + 5 HCl(g)

If 0.137 mol PCl5 completely reacts with water in this manner, calculate the following. (to the correct number of sig figs please)

(a) the number of moles of HCl produced
(b) the mass in grams of HCl produced

These are two sub questions on a worksheet that I am currently working on. I have redid this problem several times but got different numbers may someone please help me. One of the answers that I got should be correct.

I want to make sure that I am getting the right anwers, and people have been answering my questions but the answers are not correct. Can who ever works this problem out make sure that the answer is correct. I have a limited amount of submissions and questions that I can ask on chegg.

Explanation / Answer

The balanced equation is   Ni(s) + 4CO(g) Ni(CO)4(g)

Molar mass of Ni is 58.7 g/mol

Molar mass of CO is = At.mass of C + At.mass of O

                                  = 12+16 = 28 g/mol

According to the balanced equation ,

1 mole of Ni reacts with 4 moles of CO

                               OR

58.7 g of Ni reacts with 4x28 g of CO

                               OR

58.7 kg of Ni reacts with 4x28 kg of CO

4.22 kg of Ni reacts with M kg of CO

M = (4x22x4.22) / 58.7

   = 6.33kg

Therefore the mass of carbon monoxide required is 6.33 kg

-----------------------------------------------------------------------------------------------------------

PCl5(s) + 4 H2O(l) H3PO4(l) + 5 HCl(g)

According to the above balanced equation ,

1 mole of PCl5 produces 5 moles of HCl(g)

0.137 mole of PCl5 produces 5 x0.137 = 0.685 moles of HCl(g)

Therefore the number of moles of HCl produced is 0.685 mol        -----(a)

MOlar mass of HCl is = At.mass of H + At.mass of Cl

                                  = 1 + 35.5 = 36.5 g/mol

We know that number of moles , n = mass/molar mass

So mass of HCl = number of moles x molar mass

                          = 0.685 mol x 36.5 (g/mol)

                          = 25.0 g

Therefore the mass of HCl produced is 25.0 g     ------ (b)

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