Answer:
pH = 4.25
Explanation:
A solution composed of a weak acid and its conjugate base is a <em>buffer solution</em>. To calculate the pH of a buffer solution we use the Henderson-Hasselbach equation:
pH = pKa + log ([conjugate base]/[weak acid]
In this case, we have the following data:
[conjugate base] = [sodium benzoate] = 0.230 M
[weak acid] = [benzoic acid] = 0.205 M
The pKa of benzoic acid is 4.2. So, we introduce the data in the equation:
pH = 4.2 + log (0.230 M/0.205 M) = 4.2 + 0.050 = 4.25
Answer:
a) 0.714g of bicarbonate of soda are required.
b) 0.221g of Al(OH)₃ are required
Explanation:
The reactions of HCl with bicarbonate of soda and aluminium hydroxide are:
HCl + NaHCO₃ → H₂O + NaCl + CO₂
3 HCl + Al(OH)₃ → 3H₂O + AlCl₃
The moles of HCl that we need neutralize are:
50mL = 0.050L * (0.17mol / L) = 0.0085 moles HCl
To solve these problem we need to find the moles of the antacid using the chemical reaction and its mass using its molar mass;
<em>a) </em><em>Moles NaHCO₃ = Moles HCl = 0.0085 moles </em>
The mass is -Molar mass NaHCO₃: -84g/mol-
0.0085 moles * (84g / mol) = 0.714g of bicarbonate of soda are required
b) 0.0085 moles HCl * (1mol Al(OH)₃ / 3mol HCl) = 2.83x10⁻³ moles Al(OH)₃
The mass is -Molar mass: 78g/mol-:
2.83x10⁻³ moles Al(OH)₃ * (78g/mol) =
<h3>0.221g of Al(OH)₃ are required</h3>
Since the nucleophile is the actual attacking molecule or molecule that starts the reaction and allows for further steps in the mechanism to occur, it is the limiting reagent, as based on the amount of the nucleophile you have, the reaction will tend to proceed until you run out. The excess would be the sodium hydroxide, it is union part of the solution.
The starting substances in a chemical reaction are called reactants - they are written on the left side of a chemical equation.
Answer:
A covalent bond, also called a molecular bond, is a chemical bond that involves the sharing of electron pairs between atoms. These electron pairs are known as shared pairs or bonding pairs, and the stable balance of attractive and repulsive forces between atoms, when they share electrons, is known as covalent bonding
