Answer:
The concentration is 
Explanation:
From the question we are told that
The absorbance is 
The length is 
Generally absorbance is mathematically represented as
where 
is the molar absorptivity of FeSCN2 with a value 
and 
is the equilibrium concentration of FeSCN2
So
substituting values
[H+] in first brand:
4.5 = -log([H+])
[H+] = 10^(-4.5)
[H+] in second brand:
5 = -log[H+]
[H+] = 10^(-5)
Difference = 10^(-4.5) - 10^(-5)
= 2.2 x 10⁻⁵
The answer is A.
Answer:
See explanation
Explanation:
1 mole of a gas occupies 22.4 L
x moles occupies 16.8 L
x = 1 mole * 16.8 L/22.4 L
x = 0.75 moles
number of moles = mass/molar mass
mass = number of moles * molar mass
mass = 0.75 moles * 30.01 g/mol = 22.5075 g = 2.25 * 10^1 g
the coefficient of the scientific notation answer = 2.25
the exponent of the scientific notation answer = 1
significant figures are there in the answer = 6
the right most significant figure in the answer = 3
2.
number of moles = 12.5g/38g/mol = 0.3289 moles
1 mole occupies 22.4 L
0.3289 moles occupies 0.3289 moles * 22.4 L/1 mole
= 7.36736 L = 7.36736 * 10^0 L= 7.37 * 10^0 L
the coefficient of the scientific notation answer =7.37
the exponent of the scientific notation answer = 0
significant figures are there in the answer = 6
the right most significant figure in the answer= 3
Answer:
pH = 4.58
Explanation:
The reaction of NaOH with acetic acid, CH₃COOH occurs as follows:
NaOH + CH₃COOH → CH₃COO⁻Na⁺ + H₂O
<em>Moles that react:</em>
NaOH = 10mL = 0.010L * (0,240mol / L) = 0.0024 moles NaOH
CH₃COOH = 50.0mL = 0.050L * (0.120mol / L) = 0.0060 moles CH₃COOH
That means after the reaction you will have:
CH₃COOH: 0.0060 mol - 0.0024 mol = 0.0036 moles
CH₃COO⁻Na⁺: 0.0024 moles
in solution, you will have the mixture of a weak acid (Acetic acid), with its conjugate base (sodium acetate, CH₃COO⁻Na⁺). And pH of this buffer can be determined using H-H equation:
pH = pKa + log [A⁻] / [HA]
For Acetic buffer pKa = 4.76:
pH = 4.76 + log [CH₃COO⁻Na⁺] / [CH₃COOH]
<em>Where [] is molarity of each species or moles</em>
<em />
Replacing:
pH = 4.76 + log [0.0024 moles] / [0.0036 moles]
<h3>pH = 4.58</h3>
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