91Ó°ÊÓ

Understanding how to calculate the molar mass of a compound is an essential part of chemistry. It helps us quantify how much of a substance we have in terms of moles. Here's how to compute it for the compound Mg(OH)â‚‚, a common component in antacid tablets.
Mg(OH)â‚‚ consists of magnesium (Mg), oxygen (O), and hydrogen (H) atoms. To find its molar mass:

• Find the atomic masses from the periodic table: Mg (24.31 g/mol), O (16.00 g/mol), and H (1.01 g/mol).
• Since there are two oxygens and two hydrogens in each unit of Mg(OH)â‚‚, multiply their atomic masses by 2.
• Add these to the atomic mass of magnesium: 24.31 + (16.00 x 2) + (1.01 x 2).

This sums up to 58.33 g/mol for Mg(OH)â‚‚.
This calculation tells us that one mole of Mg(OH)â‚‚ weighs 58.33 grams. Thus, if you have 1.00 gram of it, you can calculate the moles by dividing the mass by the molar mass (1.00 g / 58.33 g/mol = 0.0171 mol).
Calculating molar mass is crucial for converting between grams and moles, a frequent need in chemical problem-solving.

Writing a balanced chemical equation is a fundamental skill in chemistry. It helps you understand how reactants convert into products in a reaction. For the reaction between hydrochloric acid (HCl) and magnesium hydroxide (Mg(OH)â‚‚), the balanced equation is:\[\text{Mg(OH)}_{2}\text{(s)} + 2\text{HCl(aq)} \rightarrow \text{MgCl}_{2}\text{(aq)} + 2\text{H}_2\text{O(l)}\]This equation shows that one mole of Mg(OH)â‚‚ reacts with two moles of HCl to produce one mole of MgClâ‚‚ and two moles of water (Hâ‚‚O).
The process of balancing an equation involves ensuring that the number of each type of atom on the reactant side is equal to the number on the product side.
This balanced equation provides a roadmap for calculating the amounts of reactants needed and products formed — for example, knowing that 0.0171 moles of Mg(OH)₂ can neutralize twice as many moles of HCl (0.0342 moles of HCl).
Balanced equations are essential for stoichiometry, allowing chemists to quantify relationships in chemical reactions accurately.

In the context of our exercise, molarity and volume conversion play an essential role in determining how much acid can be neutralized by a base. Molarity (M) is a measure of concentration, defined as moles of solute per liter of solution. For our case, we have the stomach acid HCl at 0.10 M.
To find out how much volume of this acid can be neutralized by Mg(OH)â‚‚, we use the relationship: \(M = \frac{\text{moles}}{\text{liters}}\)Given that 0.0342 moles of HCl can be neutralized, we set up the equation:\(0.10 \text{ M} = \frac{0.0342 \text{ mol}}{V \text{ L}}\)Solving for V gives us the volume in liters:\(V = \frac{0.0342 \text{ mol}}{0.10 \text{ M}} = 0.342 \text{ L}\)To convert liters to milliliters (since it's a more practical volume for laboratory and medical settings), multiply by 1000:\(0.342 \text{ L} \times 1000 = 342 \text{ mL}\)Understanding these conversions helps chemists in laboratory and industrial settings to prepare solutions with precise concentrations.