Question

Nickel carbonyl can be prepared by the direct combination of nickel metal with carbon monoxide gas according to the following chemical equation: $$ \mathrm{Ni}(s)+4 \mathrm{CO}(g) \longrightarrow \mathrm{Ni}(\mathrm{CO})_{4}(s) $$ Determine the mass of nickel carbonyl that can be produced by the combination of \(50.03 \mathrm{~g} \mathrm{Ni}(s)\) with \(78.25 \mathrm{~g} \mathrm{CO}(g)\). Which reactant is consumed completely? How much of the other reactant remains when the reaction is complete?

Short answer

Mass of nickel carbonyl produced: 119.1 g. CO is the limiting reactant. Remaining Ni: 9.0 g.

Step-by-step solution

Calculate Molar Masses

First, determine the molar masses of nickel (Ni) and carbon monoxide (CO). The molar mass of Ni is approximately 58.69 g/mol. The molar mass of carbon monoxide, CO, is the sum of the molar masses of carbon (12.01 g/mol) and oxygen (16.00 g/mol), which totals about 28.01 g/mol.

Convert Mass to Moles

Convert the given masses of Ni and CO to moles. For Ni:\[moles\, of\, Ni = \frac{50.03\, g}{58.69\, g/mol} \approx 0.852\, moles\]For CO:\[moles\, of\, CO = \frac{78.25\, g}{28.01\, g/mol} \approx 2.794\, moles\]

Determine Limiting Reactant

According to the reaction, 1 mole of Ni reacts with 4 moles of CO. We have 0.852 moles of Ni and need 4 times as many moles of CO:\[needed\, CO = 4 \times 0.852 = 3.408\, moles\]We only have 2.794 moles of CO, which is less than needed, so CO is the limiting reactant.

Calculate Ni(CO)_4 Produced

Since CO is the limiting reactant, use its amount to determine the mass of nickel carbonyl produced. With 4 moles of CO producing 1 mole of Ni(CO)_4, we have:\[moles\, of\, Ni(CO)_4 = \frac{2.794}{4} \approx 0.698\, moles\]Calculate mass of Ni(CO)_4 using its molar mass (170.73 g/mol):\[mass\, of\, Ni(CO)_4 = 0.698 \times 170.73 \approx 119.1\, g\]

Calculate Remaining Ni

Since CO is the limiting reactant, not all of Ni is used. The amount of Ni reacted is the same as the moles of Ni(CO)_4 produced:\[used\, Ni = 0.698\, moles\]Convert the remaining moles back to mass:\[remaining\, Ni = (0.852 - 0.698)\times 58.69 \approx 9.0\, g\]

Key concepts

Chemical Equation

A chemical equation is a representation of a chemical reaction where the substances involved are denoted by their chemical formulas. It shows the reactants, the starting substances, on the left, and the products, the substances formed, on the right. An arrow between the reactants and products signifies the direction of the reaction.

In this particular case, the chemical equation is \( \mathrm{Ni}(s) + 4 \ \mathrm{CO}(g) \longrightarrow \mathrm{Ni}(\mathrm{CO})_4(s) \). Here, nickel metal \( \mathrm{Ni}(s) \) combines with carbon monoxide gas \( \mathrm{CO}(g) \) to form nickel carbonyl \( \mathrm{Ni}(\mathrm{CO})_4(s) \).

Understanding the chemical equation is essential as it provides the stoichiometric relationship between reactants and products. Each component in the equation must be balanced to conform to the principle of conservation of mass, which implies the same number of each type of atom appears on both sides of the reaction.

Molar Mass

Molar mass is the mass of one mole of a substance, usually expressed in grams per mole (g/mol). It is a helpful bridge between the atomic world and the macroscopic scale we see in the lab.

To solve the problem, we first need the molar masses of the elements involved. For nickel \( \mathrm{Ni} \), the molar mass is approximately 58.69 g/mol. For carbon monoxide \( \mathrm{CO} \), you calculate by adding carbon's molar mass (12.01 g/mol) and oxygen's molar mass (16.00 g/mol), totaling about 28.01 g/mol.

These molar masses are crucial for converting the given masses of substances into moles, which can then be used in stoichiometric calculations to determine how many moles of each reactant will be used or formed during the reaction.

Nickel Carbonyl

Nickel carbonyl \( \mathrm{Ni}(\mathrm{CO})_4 \) is a volatile and toxic compound formed by reacting nickel with carbon monoxide. It's a coordination complex consisting of a nickel atom surrounded by four carbon monoxide ligands.

This compound plays an essential role in industrial processes such as in the Mond process, which purifies nickel by exploiting the fact that nickel carbonyl decomposes to yield pure nickel. Its formation in the given reaction is significant because it highlights the practical applications of chemical reactions in industry.

The balanced reaction already provides the stoichiometry: one mole of nickel reacts with four moles of carbon monoxide to produce one mole of nickel carbonyl. This stoichiometric relationship is used to not only predict the amount of nickel carbonyl produced but also to understand the efficiency of the reaction.

Stoichiometry

Stoichiometry is the area of chemistry that deals with the quantitative relationships between reactants and products in a chemical reaction. It's the arithmetic of chemistry and allows chemists to predict the outcomes of reactions.

In this problem, stoichiometry helps us determine the limiting reactant—carbon monoxide (CO) in this case—as we know from the chemical equation that 1 mole of nickel requires 4 moles of carbon monoxide to fully react. Given we have only 2.794 moles of CO with 0.852 moles of Ni, CO will be consumed completely before all of the nickel is used up.

Using stoichiometry, we can calculate the amount of nickel carbonyl produced. The moles of CO dictate the maximum amount of nickel carbonyl that can be formed, which is found to be approximately 0.698 moles. Knowing stoichiometry allows us to calculate other useful information like the remaining mass of unreacted nickel, reinforcing the importance of measuring and predicting chemical reactions in practical applications.