<u>Answer:</u> The mass defect for the formation of phosphorus-31 is 0.27399
<u>Explanation:</u>
Mass defect is defined as the difference in the mass of an isotope and its mass number.
The equation used to calculate mass defect follows:
![\Delta m=[(n_p\times m_p)+(n_n\times m_n)]-M](https://tex.z-dn.net/?f=%5CDelta%20m%3D%5B%28n_p%5Ctimes%20m_p%29%2B%28n_n%5Ctimes%20m_n%29%5D-M)
where,
= number of protons
= mass of one proton
= number of neutrons
= mass of one neutron
M = mass number of element
We are given:
An isotope of phosphorus which is 
Number of protons = atomic number = 15
Number of neutrons = Mass number - atomic number = 31 - 15 = 16
Mass of proton = 1.00728 amu
Mass of neutron = 1.00866 amu
Mass number of phosphorus = 30.973765 amu
Putting values in above equation, we get:
![\Delta m=[(15\times 1.00728)+(16\times 1.00866)]-30.973765\\\\\Delta m=0.27399](https://tex.z-dn.net/?f=%5CDelta%20m%3D%5B%2815%5Ctimes%201.00728%29%2B%2816%5Ctimes%201.00866%29%5D-30.973765%5C%5C%5C%5C%5CDelta%20m%3D0.27399)
Hence, the mass defect for the formation of phosphorus-31 is 0.27399
Answer:
(B) 3
Explanation:
Citric acid has an acid dissociation constant (Ka) of 8.4 × 10⁻⁴. When it forms a buffer with its conjugate base (citrate), we can calculate the pH using the Henderson-Hasselbalch's equation.
![pH=pKa+log\frac{[base]}{[acid]}](https://tex.z-dn.net/?f=pH%3DpKa%2Blog%5Cfrac%7B%5Bbase%5D%7D%7B%5Bacid%5D%7D)
The optimum range of pH is pKa ± 1. The pKa is -log Ka = -log (8.4 × 10⁻⁴) = 3.1. The buffer would be more effective for pH between 2.1 and 4.1, especially around 3.1. So the best choice is (B) 3.
Answer:
Se explanation below
Explanation:
Here we will use the technique of extraction taking advantange of the different solubilities of Phenol and and Benzoic Acid in the NaOH and and NaHCO₃ solvents (In reality their anions). Notice that phenol does not dissolve in the weak base NaHCO₃ so we can have the solution of phenol and benzoic acid in ether and proceed to extract with this weak base, the phenol will remain in solution in the organic ether solution and the sodium benzoate will go into the water layer.
We then will repeat the extraction procedure to separate the phenol from the organic layer by using NaOH instead.
Benzoic Acid /
Phenol/ Ether ⇒Extract w/ ⇒ Organic Layer = Phenol/Ether
10 % NaHCO₃ Aqueous Layer = Sodium Benzoate
Sodium benzoate ⇒ 10 % HCl to precipitate Benzoic Acid
Filter Precipitate benzoic Acid ⇒ Recrystallize benzoic Acid
Phenol / Ether Extract w/ Organic Layer = Eher
10 % NaOH Aqueous Layer =
Sodium Phenolate
Sodium Phenolate ⇒ 10% HCl to precipitate Phenol Filter Precipitate Phenol ⇒ Recrystallize Phenol
Answer:
How can we make use of acids or bases to remove heavy metals from soils? We can remove heavy metals from soil by adding acid and catching the solution that drains through. Acids can react with metals turning metalic compounds which can be dissolved by water and washed away. Improve crop yields?
Explanation:
C = Carbon
CO = Carbon Monoxide
Co = Cobalt
O2 = Oxygen
So the answer is (3) CO
