Answer:
HCl(aq) + KOH(aq) ⇒ KCl(aq) + H₂O(l)
Explanation:
Hydrochloric acid is an acid because it releases H⁺ in an aqueous solution.
Potassium hydroxide is a base because it releases OH⁻ in an aqueous solution.
When an acid reacts with a base they form a salt and water. This is a neutralization reaction. The neutralization reaction between hydrochloric acid and potassium hydroxide is:
HCl(aq) + KOH(aq) ⇒ KCl(aq) + H₂O(l)
The number of grams of NaOH that are needed to make 500 ml of 2.5 M NaOH solution
calculate the number of moles =molarity x volume/1000
= 2.5 x 500/1000 = 1.25 moles
mass = moles x molar mass of NaOH
= 1.25 x40= 50 grams of NaOH
Answer:
The molar mass of the unknown substance is 255g/mole
Explanation:
Freezing point depression is given by
ΔT = i · Kf · m
Where
m = molality of the solute
i = van't Hoff's factor = i for non electrolyte
Kf = 20.4 °C/m = cryoscopic constant
ΔT = Freezing point depression
Therefore ΔT = 6.6 - 5 = 1.6 °C
1.6 °C = 20.4 °C/m × 1 × m
Therefore m = 1.6/20.4 = 0.0784 m
number of moles in 2.50 g of cyclohexane = 0.0784 m or 0.0784 moles of the substance in 1000 grams of cyclohexane. That is
2.5 ×0.0784/1000 moles in 2.5 graams of cyclohexane that is
1.96 × 10⁻⁵ moles in 2.5 grams of cyclohexane
1.96 × 10⁻⁵ moles of the substance weighs 0.050 grams
Therefore 1 Mole weighs (0.05 g)/(1.96 × 10⁻⁵ moles) = 255g/mole
