Answer:
The unknown NaOH base has a concentration of 0.636M
Explanation:
<u>Step 1:</u> the balanced equation
NaOH + HCl → NaCl + H2O
This means for 1 mole of NaOH consumed there is 1 mole of HCl needed to produce 1 mole of NaCl and 1 mole of H2O
<u>Step 2</u>: Calculate moles of HCl used
Number of moles = Concentration * volume = 0.5M * 25*10^-3 L =0.0125 moles
<u>Step 3</u>: Calculate moles of NaOH
Since the mole ratio for HCl and NaOH is 1:1 this means we have 0.0125 moles of NaOH for 0.0125 moles of HCl
<u>Step 4:</u> Calculate Concentration of the unknown NaOH base
Concentration = Number of moles / Volume
Volume of NaOH = 24.64-5 =19.64 mL = 0.01964 L
Concentration = 0.0125/0.01964 = 0.636 M
The unknown NaOH base has a concentration of 0.636M
Answer:
D. Acidic salt
Explanation:
Acidic salts:
Salts formed by incomplete neutralisation of poly-basic acids are called acidic salts. Such salts still contain one or more replaceable hydrogen atoms. These salts when neutralised by bases form normal salts.
The reaction is:
6 Cr²⁺ + Cr₂O₇²⁻ + 14 H⁺ → 8 Cr³⁺ + 7 H₂O
E₀ = 1.33 - (-0.5) = 1.83 V
ΔG = - n f E₀
= - 6 * 96485 * 1.83
= - 1059405.3 J / mol
= - 1059.4 kJ / mol
The formula of density is mass / volume
This means that
- high mass, low volume = high density
- high mass, high volume = so-so
- low mass, high volume = low density
From the graph shown,
D has the lowest density because it has low mass yet high volume.
