The correct answer is option B, that is, add 1.46 grams of NaCl to 250 milliliters of H₂O.
First there is a need to find the moles of NaCl in 250 ml of 0.10 M NaCl,
Moles of NaCl = molarity × volume = 0.10 M × (250/1000L) = 0.025 mol
The corresponding mass of NaCl is,
Mass of NaCl = moles × molar mass = 0.025 mol × 58.5 g/mol = 1.46 g
Thus, there is a need to dissolve 1.46 grams of NaCl solid into 50 ml of H₂O and dilute to 250 ml.
Answer:
2.5 × 10⁻⁵ M H₃O⁺ and 4.0 × 10⁻¹⁰ M OH⁻.
Explanation:
<em>∵ pH = - log[H₃O⁺]</em>
∴ 4.6 = - log[H₃O⁺].
∴ log[H₃O⁺] = - 4.6.
∴ [H₃O⁺] = 2.51 x 10⁻⁵.
∵ [H₃O⁺][OH⁻] = 10⁻¹⁴.
[H₃O⁺] = 2.51 x 10⁻⁵ M.
∴ [OH⁻] = 10⁻¹⁴/[H₃O⁺] = 10⁻¹⁴/(2.51 x 10⁻⁵ M) = 3.98 × 10⁻¹⁰ M ≅ 4.0 × 10⁻¹⁰ M.
<em>So, the right choice is: 2.5 × 10⁻⁵ M H₃O⁺ and 4.0 × 10⁻¹⁰ M OH⁻.</em>
Answer:
CH3COOH would be more concentrated
Explanation:
The higher the concentration value, the more concentrated it is.
The relationship between concentration, moles and volume is given by the equation;
Concentration = No of moles / Volume
5.0 grams of HCOOH dissolved in 189 mL of water
Number of moles = Mass / Molar mass = 5 / 46.03 = 0.1086 mol
Concentration = 0.1086 / 0.189 = 0.5746 mol/L
1.5 moles of CH3COOH dissolved in twice as much water
Volume = 2 * 189 = 378 ml = 0.378 L
Concentration = 1.5 / 0.378 = 3.9683 mol/L
Comparing both concentration values;
CH3COOH would be more concentrated
(7.3 x 10^29 atoms) / (24 atoms/molecule) / (6.022 x 10^23 molecules/mol) =
5.1 x 10^4 mol C6H12O6
, carboxyl group exists as
(charged)
(neutral)
(charged)
