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Ch.3 - Chemical Reactions and Reaction Stoichiometry
Brown - Chemistry: The Central Science 15th Edition
Brown15th EditionChemistry: The Central ScienceISBN: 9780137542970Not the one you use?Change textbook
Chapter 3, Problem 97b

A method used by the U.S. Environmental Protection Agency (EPA) for determining the concentration of ozone in air is to pass the air sample through a 'bubbler' containing sodium iodide, which removes the ozone according to the following equation: O31g2 + 2 NaI1aq2 + H2O1l2¡ O21g2 + I21s2 + 2 NaOH1aq2 (b) How many grams of sodium iodide are needed to remove 1.3 mg of O3?

Verified step by step guidance
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Step 1: Convert the mass of ozone from milligrams to grams. This is done by dividing the given mass by 1000, since there are 1000 milligrams in a gram.
Step 2: Calculate the number of moles of ozone. This is done by dividing the mass of ozone (in grams) by its molar mass. The molar mass of ozone (O3) is approximately 48 g/mol.
Step 3: Use the stoichiometry of the reaction to find the number of moles of sodium iodide (NaI) needed. According to the balanced chemical equation, two moles of NaI react with one mole of O3. Therefore, the number of moles of NaI needed is twice the number of moles of O3.
Step 4: Calculate the mass of sodium iodide needed. This is done by multiplying the number of moles of NaI by its molar mass. The molar mass of NaI is approximately 150 g/mol.
Step 5: The result from step 4 is the mass of sodium iodide needed to remove the given amount of ozone. This is the final answer.

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Stoichiometry

Stoichiometry is the branch of chemistry that deals with the quantitative relationships between the reactants and products in a chemical reaction. It allows chemists to calculate how much of a substance is needed or produced in a reaction based on balanced chemical equations. In this case, understanding the stoichiometric coefficients from the provided reaction is essential to determine the amount of sodium iodide required to react with a specific mass of ozone.
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Molar Mass

Molar mass is the mass of one mole of a substance, typically expressed in grams per mole (g/mol). It is crucial for converting between the mass of a substance and the number of moles, which is necessary for stoichiometric calculations. For sodium iodide (NaI), knowing its molar mass allows us to calculate how many grams are needed to react with the given amount of ozone.
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Concentration and Mass Conversion

Concentration refers to the amount of a substance in a given volume of solution, while mass conversion involves changing units from mass to moles or vice versa. In this problem, converting the mass of ozone (1.3 mg) to moles is necessary to use stoichiometry effectively. This conversion is essential for determining how much sodium iodide is needed to completely react with the ozone present in the air sample.