Ch.4 - Chemical Quantities & Aqueous ReactionsWorksheetSee all chapters
All Chapters
Ch.1 - Intro to General Chemistry
Ch.2 - Atoms & Elements
Ch.3 - Chemical Reactions
BONUS: Lab Techniques and Procedures
BONUS: Mathematical Operations and Functions
Ch.4 - Chemical Quantities & Aqueous Reactions
Ch.5 - Gases
Ch.6 - Thermochemistry
Ch.7 - Quantum Mechanics
Ch.8 - Periodic Properties of the Elements
Ch.9 - Bonding & Molecular Structure
Ch.10 - Molecular Shapes & Valence Bond Theory
Ch.11 - Liquids, Solids & Intermolecular Forces
Ch.12 - Solutions
Ch.13 - Chemical Kinetics
Ch.14 - Chemical Equilibrium
Ch.15 - Acid and Base Equilibrium
Ch.16 - Aqueous Equilibrium
Ch. 17 - Chemical Thermodynamics
Ch.18 - Electrochemistry
Ch.19 - Nuclear Chemistry
Ch.20 - Organic Chemistry
Ch.22 - Chemistry of the Nonmetals
Ch.23 - Transition Metals and Coordination Compounds

Solution: What mass of potassium carbonate (molar mass = 138.21 mol-1) is needed to prepare 450. mL of an aqueous solution with a potassium concentration of 0.475 M?A. 29.5 gB. 1.33 x 104 gC. 13.3 gD. 14.8 gE.

Problem

What mass of potassium carbonate (molar mass = 138.21 mol-1) is needed to prepare 450. mL of an aqueous solution with a potassium concentration of 0.475 M?

A. 29.5 g

B. 1.33 x 104 g

C. 13.3 g

D. 14.8 g

E. 6.65 g

Solution

We’re being asked to calculate the mass of potassium (K2CO3) carbonate needed to prepare 450. mL of an aqueous solution with a potassium concentration of 0.475 M.


Recall that molarity is the ratio of the moles of solute and the volume of solution (in liters). In other words:


Molarity (M) = moles of soluteLiters of solution


We first need to determine the number of moles of potassium (K+). 


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