Question

Silicon is produced for the chemical and electronics industries by the following reactions. Give the balanced equation for each reaction. a. \(\operatorname{Si} \mathrm{O}_{2}(s)+\mathrm{C}(s) \longrightarrow \mathrm{Si}(s)+\mathrm{CO}(g)\) b. Silicon tetrachloride is reacted with very pure magne- sium, producing silicon and magnesium chloride. c. \(\mathrm{Na}_{2} \mathrm{SiF}_{6}(s)+\mathrm{Na}(s) \longrightarrow \mathrm{Si (s)+\mathrm{NaF}(s)\)

Short answer

The balanced equations for each reaction are: a. \(\mathrm{SiO_2}(s) + \mathrm{C}(s) \longrightarrow \mathrm{Si}(s) + \mathrm{CO}(g)\) b. \(\mathrm{SiCl_4} + 2\mathrm{Mg} \longrightarrow \mathrm{Si} + 2\mathrm{MgCl_2}\) c. \(\mathrm{Na_2SiF_6}(s) + 3\mathrm{Na}(s) \longrightarrow \mathrm{Si}(s) + 6\mathrm{NaF}(s)\)

Step-by-step solution

Balancing Reaction a)

Given the equation: \(\mathrm{SiO_2}(s) + \mathrm{C}(s) \longrightarrow \mathrm{Si}(s) + \mathrm{CO}(g)\) This equation is already balanced, and there is no need to add any coefficients. Balanced equation: \(\mathrm{SiO_2}(s) + \mathrm{C}(s) \longrightarrow \mathrm{Si}(s) + \mathrm{CO}(g)\)

Balancing Reaction b)

Given the information: Silicon tetrachloride (SiCl₄) reacts with very pure magnesium (Mg) to produce silicon (Si) and magnesium chloride (MgCl₂). First, write the unbalanced equation: \(\mathrm{SiCl_4} + \mathrm{Mg} \longrightarrow \mathrm{Si} + \mathrm{MgCl_2}\) Now, we need to balance it. There is one Si on both sides, but four Cl on the left side and two Cl on the right side. To fix this, add a coefficient of 2 in front of MgCl₂ on the right. So, the equation becomes: \(\mathrm{SiCl_4} + \mathrm{Mg} \longrightarrow \mathrm{Si} + 2\mathrm{MgCl_2}\) Now there are four Cl on both sides, but there are two Mg on the right side and only one Mg on the left side. To fix this, add a coefficient of 2 in front of Mg on the left. Balanced equation: \(\mathrm{SiCl_4} + 2\mathrm{Mg} \longrightarrow \mathrm{Si} + 2\mathrm{MgCl_2}\)

Balancing Reaction c)

Given the equation: \(\mathrm{Na_2SiF_6}(s) + \mathrm{Na}(s) \longrightarrow \mathrm{Si}(s) + \mathrm{NaF}(s)\) First, balance the Si atoms. There is already one Si atom on both sides, so it is balanced. Next, balance the F atoms. There are 6 F atoms on the left side and 1 F atom on the right side. To fix this, add a coefficient of 6 in front of NaF on the right. So, the equation becomes: \(\mathrm{Na_2SiF_6}(s) + \mathrm{Na}(s) \longrightarrow \mathrm{Si}(s) + 6\mathrm{NaF}(s)\) Now, balance the Na atoms. There are 2 Na atoms on the left side and 6 Na atoms on the right side. To fix this, add a coefficient of 3 in front of Na on the left. Balanced equation: \(\mathrm{Na_2SiF_6}(s) + 3\mathrm{Na}(s) \longrightarrow \mathrm{Si}(s) + 6\mathrm{NaF}(s)\)

Key concepts

balancing equations

Balancing chemical equations is a crucial skill in chemistry that ensures the law of conservation of mass is upheld. It involves adjusting the coefficients of reactants and products so that the number of atoms for each element is the same on both sides of the equation. This doesn't change the substances involved but ensures mass is conserved overall.
For example, in the reaction of silicon dioxide with carbon to produce silicon and carbon monoxide, the equation \[\mathrm{SiO_2}(s) + \mathrm{C}(s) \longrightarrow \mathrm{Si}(s) + \mathrm{CO}(g)\] is balanced as is. There’s one silicon, one carbon, and two oxygen atoms on both sides.

• Check each element’s atoms on both sides of the equation.
• Adjust coefficients as necessary to balance the atoms.
• Coefficients must be the smallest set of whole numbers possible.

In more complex reactions like the production of silicon using silicon tetrachloride and magnesium, coefficients often require more adjustments to ensure all atoms are accounted for. Remember, balance each type of atom individually without altering subscripts.

silicon production

Silicon is a critical element, especially in the electronics industry, and its production involves several fascinating chemical reactions. One common method to produce it involves reducing silicon dioxide with carbon. While the reaction \[\mathrm{SiO_2}(s) + \mathrm{C}(s) \longrightarrow \mathrm{Si}(s) + \mathrm{CO}(g)\] produces silicon by simplifying the compound structure, no additional balancing is needed in this case.
Silicon is also extracted by using silicon tetrachloride. The reaction with magnesium is particularly important as it produces high-purity silicon needed for electronic applications. With the reaction:\[\mathrm{SiCl_4} + 2\mathrm{Mg} \longrightarrow \mathrm{Si} + 2\mathrm{MgCl_2}\],
very pure magnesium aids in the efficient separation of silicon from chlorine and magnesium, yielding pure silicon.
Lastly, silicon production can also include sodium hexafluorosilicate in reactions producing both sodium fluoride and pure silicon. This helps in applications where silicon's electric properties are essential. Each of these reactions must be carefully balanced and controlled for optimal silicon extraction.

stoichiometry

Stoichiometry is the study of the quantitative relationships between reactants and products in a chemical reaction. It relies heavily on the balanced equations to determine the proportions of substances involved. For instance, in the production reactions for silicon, precise stoichiometric calculations help ascertain the right amounts of each reactant needed.
Consider the reaction of silicon tetrachloride and magnesium, where the balanced equation is:\[\mathrm{SiCl_4} + 2\mathrm{Mg} \longrightarrow \mathrm{Si} + 2\mathrm{MgCl_2}\]. Using stoichiometry, one can predict how much silicon and magnesium chloride will be produced given specific amounts of SiCl₄ and Mg.

• The coefficients in balanced equations indicate the molar ratio of reactants to products.
• For accurate reactions, ensure the use of balanced equations.
• Convert between moles, mass, and number of molecules using Avogadro’s number.

Therefore, stoichiometry is essential for avoiding waste and for optimizing the chemical processes, particularly in industrial applications where efficiency is key.