Question

The number of moles of hydroxide ion in 0.300 L of \(0.0050 \mathrm{M} \mathrm{Ba}(\mathrm{OH})_{2}\) is (a) \(0.0015 ;(\mathrm{b}) 0.0030 ;(\mathrm{c}) 0.0050\) (d) 0.010.

Short answer

So, the number of moles of hydroxide ion in 0.300 L of 0.0050 M Ba(OH)2 solution is 0.0030 moles (option b).

Step-by-step solution

Identifying the given variables

In our problem, the concentration [C] of barium hydroxide is 0.0050 M and the volume [V] given is 0.300L.

Formulate the relationship

Ba(OH)2 \[ \rightarrow \] Ba2+ + 2OH-, from one formula unit of Ba(OH)2 we get 2 hydroxide ions. Thus, the concentration of hydroxide ions is twice the concentration of the barium hydroxide.

Calculate the moles of Ba(OH)2

To calculate the moles (n) of Ba(OH)2, use the formula n = C x V. Substituting the given values, number of moles of Ba(OH)2 = 0.0050 M x 0.300L = 0.0015 moles.

Resolve for the concentration of OH⁻

Since each mole of Ba(OH)2 produces 2 moles of OH⁻, the number of moles of OH⁻ will be 2 times the moles of Ba(OH)2. The moles of OH⁻ is therefore = 2 x 0.0015 moles = 0.0030 moles.

Key concepts

Barium hydroxide

Barium hydroxide, with the chemical formula \( ext{Ba(OH)}_2\), is an inorganic compound used in various applications such as chemistry and industry. It is often utilized in laboratory settings for titration and analytical procedures due to its reliable reaction properties.

When dissolved in water, barium hydroxide dissociates completely to produce barium ions (\( ext{Ba}^{2+}\)) and hydroxide ions (\( ext{OH}^-\)). This ability to produce hydroxide ions makes it particularly useful for pH adjustment and chemical reactions that require a strong base. Understanding how barium hydroxide dissociates in solution is crucial when determining the chemical concentration and behavior in reactions. By knowing the concentration of barium hydroxide, one can calculate important parameters such as the pH of the solution and the number of moles of hydroxide ions produced.

Hydroxide ion

The hydroxide ion (\( ext{OH}^-\)) plays a vital role in many chemical reactions and is known for its basic properties. It is composed of one oxygen atom and one hydrogen atom, carrying a negative charge.

In aqueous solutions, the hydroxide ion is a strong base because it can accept protons from acids. This property allows it to neutralize acids in various chemical processes.

• One of the most notable features of the hydroxide ion is its ability to affect the pH level of solutions, increasing the alkalinity when present in higher concentrations.
• Neutralization reactions involving hydroxide ions are essential in titrations, where the unknown concentration of an acidic solution is determined by reacting it with a base like a hydroxide ion.

Understanding the behavior and calculation of the number of hydroxide ions in a solution is essential for any chemistry student, especially when dealing with compounds like barium hydroxide.

Chemical concentration

Chemical concentration refers to the amount of a substance present in a given volume of solution. Expressed often in terms of molarity (M), which is moles per liter (mol/L), concentration is a crucial parameter in chemistry as it dictates the reactivity and properties of a solution.

In our context, calculating the concentration is essential for understanding how much barium hydroxide is present in a given volume of solution. If you know the concentration, you can predict the behavior of the solution in chemical reactions.

• Higher concentration indicates more dissolved particles, which typically increases the reactivity of the solution.
• Concentration plays a key role in stoichiometry calculations, where balanced chemical equations are used to predict products and reactants.

By grasping the concept of concentration, students can better understand the dynamics of chemical reactions as well as accurately carry out calculations necessary for laboratory settings.

Stoichiometry

Stoichiometry is the branch of chemistry concerned with the quantities of reactants and products in chemical reactions. It allows chemists to predict the outcomes of reactions quantitatively. This field involves using balanced chemical equations to relate the amounts of reactants used to the amounts of products formed.

In the provided problem, stoichiometry comes into play when we calculate the number of hydroxide ions produced from barium hydroxide. One formula unit of \( ext{Ba(OH)}_2\) dissociates to form two hydroxide ions, doubling the concentration of produced \( ext{OH}^-\) ions compared to the original barium hydroxide concentration.

• Understanding stoichiometry is crucial for solving problems involving moles, mass, volume, and concentration.
• It helps in planning practical applications, like ensuring sufficient reactant quantities are available for desired reactions.

Stoichiometry not only guides chemists in practical laboratory tasks but also deepens their understanding of how reactions occur at the molecular level, allowing for more accurate and efficient chemical experimentation and application.