Answer:
Kf = 9.96x10⁴¹
Explanation:
When Fe³⁺ and CN⁻ are in water, complex Fe(CN)₆³⁻ is formed, thus:
Fe³⁺ + 6CN⁻ ⇄ Fe(CN)₆³⁻
Kf is defined as:
Kf = [Fe(CN)₆³⁻] / [Fe³⁺] [CN⁻]⁶
Equilibrium concentration of ions is:
[Fe(CN)₆³⁻] = 1.5x10⁻³M
[Fe³⁺] = 8.5x10⁻⁴⁰
[CN⁻] = [KCN] = 0.11M
Replacing in Kf expression:
Kf = [1.5x10⁻³M] / [8.5x10⁻⁴⁰] [ 0.11M]⁶
<h3>Kf = 9.96x10⁴¹</h3>
Answer: 2.8275grams
Explanation: A buffer is made btw a weak acid and it salt. In a solution made by dissolving a weak acid in solution, equilibrium is set up btw ionised and unionised ion. For Benzoic acid
C6H5COOH....> C6H5COO- + H+
Ka = [C6H5COO-] [H+]/ [C6H5COOH].......(1)
using Ka = 6.5× 10^-5, [C6H5COOH] = 0.02M. PH= - log[H+] ....> [H+]= 10^-4M.
Putting the values in(1)
[C6H5COO-]= 6.5× 10^-5 × 0.02/ 10^-4
[C6H5COO-] = 0.013M = Molarity of sodium benzoate
Mole(C6H5COONa) = 0.013 × Volume = 0.013mol/litre × 1.5 litre
Mole(C6H5COONa) = 0.0195mol
Mass(C6H5COONa) = 0.0195 × Molar mass
Mass(C6H5COONa) = 2.8275g
Answer:
Stone does not have organic matter in it to burn in presence of air. Hence, it is a non combustible.
Rocks are quite bundled up together. Hence, they are very difficult to get mixed together.
Answer:b.CaCl2
Explanation:
A compound is a substance resulting when two or more elements are are chemically bonded together either ionically or covalently in a fixed ratio.
From the given options we can see that the only compound there is CaCl2 which is an ionic compound in the fixed ratio of one calcium ion to two chloride ions.
Other options , Cu,Na and Nd are merely pure substance---Elements
The value of ΔG° at this temperature is -18034.18 J/mol
Calculation,
Given information
formation constant (Kf)= 1.7 × 
Universal gas constant (R) = 8.314 J/K• mol
Temperature = 25° C = 25 °C + 273 = 300 K
Formula used:
ΔG° = -RT㏑Kf
By putting the valur of R,T, Kf we get the value of ΔG°
ΔG° = - 8.314 J/K• mol×300K㏑ 1.7 ×
ΔG° = -2494.2㏑ 1.7 × = -18034.18 J/mol
So, change in standard Gibbs's free energy is -18034.18 J/mol
Learn about formation constant
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