Delta Hf = dHf
<span>dHf rxn = (n*dHf products) - (n*dHf reactants). </span>
<span>Substitute 5113.3 kJ for dHf rxn and solve for the only unknown in the equation which is dHf C8H18.
</span>-5133.3-[(8x-393.5)+9(-241.8)] = 190.9
<span>Since it is an enthalpy of formation, the value has to be negative, </span>
<span>thus the correct answer is -190.9</span>
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
A.helium<span>Hydrogen is the most abundant element in the Universe; helium is second. However, after this, the rank of abundance does not continue to correspond to the atomic number; oxygen has abundance rank 3, but atomic number 8.</span>
Answer: D, hydrolysis
Hydrolysis is any chemical reaction in which a molecule of water ruptures one or more chemical bonds. The term is used broadly for substitution, elimination, and fragmentation reactions in which water is the nucleophile.
We are given with the initial volume of the substance and the molarity. The first thing that needs to be done is to multiply the equation in order to obtain the number of moles such as shown below.
number of moles = (40 mL) x (1 L / 1000 mL) x (0.3433 moles / L)
number of moles = 0.013732 moles
To get the value of the molarity of the diluted solution, we divide the number of moles by the total volume.
molarity = (0.013732 moles) / (750 mL / 1000 mL/L) = 0.0183 M
Similarly, we can solve for the molarity by using the equation,
M₁V₁ = M₂V₂
Substituting the known values in the equation,
(0.3433 M)(40 mL) = M₂(750 mL)
M₂ = 0.0183 M