Concentration
Definition
In chemistry, concentration refers to the amount of a substance per defined space. It's usually measured in terms of mass per volume.
Analogy
Think of making lemonade - the more lemons (or lemon juice) you add to a certain amount of water, the stronger (more concentrated) your lemonade will be.
Related terms
Molarity: This is a measure of concentration in terms of moles per liter. If we stick with our lemonade analogy, it would be like measuring how many whole lemons are squeezed into each glass.
Solubility: This term describes how much solute can dissolve in a solvent at a given temperature. Like figuring out how much sugar you can stir into your lemonade before it just won't dissolve anymore.
Dilution: This is the process of reducing the concentration by adding more solvent (like water). If your lemonade is too strong, you'd dilute it by adding more water.
"Concentration" appears in:
Subjects (2)
Study guides (8)
AP Chemistry - 3.7 Solutions and Mixtures
AP Chemistry - 5.1 Reaction Rates
AP Chemistry - 5.4 Elementary Reactions
AP Chemistry - 7.9 Introduction to Le Châtelier’s Principle
AP Chemistry - 7.10 Reaction Quotient and Le Châtelier’s Principle
AP Chemistry - 8.2 pH and pOH of Strong Acids and Bases
AP Chemistry - 8.10 Buffer Capacity
AP Chemistry - 9.9 Cell Potential Under Nonstandard Conditions
Practice Questions (20+)
- Consider a solution of 0.001M KI and 0.1M KCl. If Ag⁺ ions are added, what concentration is needed to begin causing AgI to form precipitate? (Ksp of 1.5 x 10⁻¹⁶)
- Consider the reaction CO (g) + 2H₂ (g) ⇌ CH₃OH (g). If the given K constant is 500, what is a possible distribution of the concentration of the substances?
- A solution has a concentration of 3.6x10-8M hydrogen ions. Which of the following is true?
- The concentration of hydrogen ions in a 0.10 M solution of HCNO is 0.0010 M. Calculate the Kₐ for HCNO.
- A + 3B ⇌ 2C + 2D is at equilibrium. The initial concentration of A is 1.2 M, and the initial concentration of B is 1.5 M. The concentration of C at equilibrium is 0.6 M. What is the equilibrium constant, K?
- Given that Kb = 6.3x10^-5, find the concentration of the hydroxide anion in a 0.25 M solution of (CH3)3N.
- What is the concentration of 1.55 M NaOH is required to titrate 24 mL of a 0.75 M HI solution?
- A student fills a buret with 50mL of .200M LiOH. The student carefully adds 20.00mL LiOH to react with and neutralize 100.0mL of HClO₃. What is the concentration of the acid?
- Which of the following statements is true about the effect of concentration on the rate of an enthalpy-driven reaction versus an entropy-driven reaction?
- Which of the following is true about the effect of concentration on the cell potential of an electrochemical cell?
- Which of the following is true about the effect of increasing the concentration of a product on the cell potential of an electrochemical cell?
- Which of the following is true about the effect of increasing the concentration of the electrolyte on the rate of electrolysis?
- The rate law for the following reaction is R = k[XY]^2. The initial rate of the reaction was found to be 0.16 mol/Ls when the initial concentration of XY is 0.40 mol/L. What is the value of the rate constant, k?
- Rate and concentration are always in what units?
- The rate law for the following reaction is R = k[A]^2. The initial rate of the reaction is defined as 0.080 mol/Ls, whereas the initial concentration of X is 0.20 mol/L. What is the value of the rate constant, k, for this reaction?
- A reaction is represented by the equation 2X + A -> XA + X. A plot of the concentration of A versus time, shown below, was found to have a negative slope. What is the order of the reaction with respect to A?
- In a first order reaction, a rate constant of 0.33 min^-1 is present. It will take how many minutes for the concentration to decrease from 0.13 M to 0.088 M?
- When conducting a reaction, its reaction rate increased by a factor of 9 as the concentration of B tripled. What order is the reaction for B?
- How does increasing the concentration help increase the reaction rate?
- A reaction is shown to occur at 298 K, and equilibrium is reached. The reaction proceeds as follows: 2A⇌B. It is found that the concentration of B is found to be 0.5 M and the concentration of A is 2.0 M. What is the equilibrium constant for this reaction?
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