(a) How many grams of ethanol, CH3CH2OH, should you dissolve in water to make 1.00 L of vodka (which is an aqueous solution that is 6.86 M ethanol)? (b) Using the density of ethanol (0.789 g/mL), calculate the volume of ethanol you need to make 1.00 L of vodka.
Ch.4 - Reactions in Aqueous Solution
Chapter 4, Problem 69b
(b) Which will contain the greater number of moles of potassium ion: 30.0 mL of 0.15 M K2CrO4 or 25.0 mL of 0.080 M K3PO4

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Calculate the moles of K_2CrO_4 in 30.0 mL of 0.15 M solution using the formula: moles = concentration (M) \times volume (L).
Determine the number of moles of potassium ions (K^+) in K_2CrO_4 by recognizing that each formula unit of K_2CrO_4 contains 2 moles of K^+.
Calculate the moles of K_3PO_4 in 25.0 mL of 0.080 M solution using the formula: moles = concentration (M) \times volume (L).
Determine the number of moles of potassium ions (K^+) in K_3PO_4 by recognizing that each formula unit of K_3PO_4 contains 3 moles of K^+.
Compare the moles of potassium ions from both solutions to determine which contains the greater number of moles of potassium ion.

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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Molarity (M)
Molarity is a measure of concentration defined as the number of moles of solute per liter of solution. It is expressed in moles per liter (mol/L). Understanding molarity is essential for calculating the number of moles present in a given volume of solution, which is crucial for this question.
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Stoichiometry
Stoichiometry involves the calculation of reactants and products in chemical reactions based on the balanced chemical equations. In this context, it helps determine the number of moles of potassium ions produced from the given compounds, K<sub>2</sub>CrO<sub>4</sub> and K<sub>3</sub>PO<sub>4</sub>, by analyzing their formulas and the number of potassium ions they contain.
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Conversion of Volume to Moles
To find the number of moles from a solution, one can use the formula: moles = molarity × volume (in liters). This conversion is necessary to compare the moles of potassium ions in the two solutions provided in the question, allowing for a direct comparison of their quantities.
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Indicate the concentration of each ion present in the solution formed by mixing: (a) 42.0 mL of 0.170 M NaOH with 37.6 mL of 0.400 M NaOH.
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