Problem 89 - Chemistry The Science in Context

Question

Sodium chloride (NaCl) contains 1.54 g of Cl for every \(1.00 \mathrm{g}\) of \(\mathrm{Na} .\) Which of the following mixtures would react to produce sodium chloride with no Na or Cl left over? a. \(11.0 \mathrm{g}\) of \(\mathrm{Na}\) and \(17.0 \mathrm{g}\) of \(\mathrm{Cl}\) b. \(6.5 \mathrm{g}\) of \(\mathrm{Na}\) and \(10.0 \mathrm{g}\) of \(\mathrm{Cl}\) c. \(6.5 \mathrm{g}\) of \(\mathrm{Na}\) and \(12.0 \mathrm{g}\) of \(\mathrm{Cl}\) d. \(6.5 \mathrm{g}\) of \(\mathrm{Na}\) and \(8.0 \mathrm{g}\) of \(\mathrm{Cl}\)

Step-by-Step Solution

Answer

Answer: a) 11.0 g of Na and 17.0 g of Cl and b) 6.5 g of Na and 10.0 g of Cl

Step 1 - Calculate the required mass of Cl for each mixture using the given ratio

For each mixture, we need to calculate the required mass of Cl to react completely with the given mass of Na. We can do this using the given mass ratio: Required mass of Cl = (mass of Na × 1.54 g Cl) / 1.00 g Na

Step 2 - Compare the required mass of Cl with the actual mass of Cl in each mixture

For a mixture to react completely, the actual mass of Cl should be equal to the required mass of Cl. We will compare these values for each mixture: a. Mass of Na = 11.0 g Required mass of Cl = (11.0 g Na × 1.54 g Cl) / 1.00 g Na = 16.94 g Cl Actual mass of Cl = 17.0 g 16.94 g Cl ≈ 17.0 g Cl b. Mass of Na = 6.5 g Required mass of Cl = (6.5 g Na × 1.54 g Cl) / 1.00 g Na = 10.01 g Cl Actual mass of Cl = 10.0 g 10.01 g Cl ≈ 10.0 g Cl c. Mass of Na = 6.5 g Required mass of Cl = (6.5 g Na × 1.54 g Cl) / 1.00 g Na = 10.01 g Cl Actual mass of Cl = 12.0 g 10.01 g Cl ≠ 12.0 g Cl d. Mass of Na = 6.5 g Required mass of Cl = (6.5 g Na × 1.54 g Cl) / 1.00 g Na = 10.01 g Cl Actual mass of Cl = 8.0 g 10.01 g Cl ≠ 8.0 g Cl

Step 3 - Determine which mixture will react completely

Based on our comparison in Step 2, we can see that Mixtures a and b have nearly equal required and actual mass of Cl, which means both mixtures would react completely to produce sodium chloride with no Na or Cl left over. Therefore, the answer is a) \(11.0 \mathrm{g}\) of \(\mathrm{Na}\) and \(17.0 \mathrm{g}\) of \(\mathrm{Cl}\) and b) \(6.5 \mathrm{g}\) of \(\mathrm{Na}\) and \(10.0 \mathrm{g}\) of \(\mathrm{Cl}\).

Key Concepts

Chemical Reactions

In chemistry, a reaction occurs when two or more substances, known as reactants, transform into different substances, called products. This transformation involves the making or breaking of chemical bonds, leading to a re-arrangement of atoms.
A good example of a chemical reaction is the formation of sodium chloride (table salt) from sodium (Na) and chlorine gas (Cl extsubscript{2}). In this particular reaction, sodium and chlorine react to form a new compound, sodium chloride (NaCl).
Chemical reactions obey the law of conservation of mass. This means the mass of reactants must equal the mass of the products. As such, balancing equations is crucial so that each element has the same quantity of atoms on both sides of the equation.

Mass Ratio

The concept of mass ratio is important to determine how much of each reactant you need for a reaction to complete without any leftover. In the case of sodium chloride formation, for every 1 gram of sodium (Na), you will need 1.54 grams of chlorine (Cl) to fully react and form the compound.
Knowing the mass ratio is useful when mixing substances to ensure that all the reactants are used up entirely, which is ideal in chemical processes and reactions.

• It helps in calculating the exact amounts of each reactant to be mixed.
• It prevents waste of reactants.
• It helps to predict the amount of product that can be formed from given reactants.

Sodium Chloride Synthesis

Sodium chloride synthesis is the process of creating table salt by reacting sodium with chlorine. Sodium is a highly reactive metal, and chlorine is a reactive non-metal. When these two elements come into contact, they undergo a vigorous chemical reaction.
In this synthesis,

• Sodium loses an electron to form a positively charged ion (Na extsuperscript{+}).
• Chlorine gains an electron to form a negatively charged ion (Cl extsuperscript{−}).
• The opposite charges attract, resulting in the formation of sodium chloride (NaCl), a stable ionic compound.

This process is a classic example of an exothermic reaction, where energy is released as the compound forms.