The scientist who wrote the universal law of gravitation was Sir Isaac Newton.
Answer:
C. II, III, IV, and V.
Explanation:
Acid buffer is generally formed by the combination of a weak acid as well as the salt of the conjugate base.
Basic buffer is formed the combination of a weak base and also the salt of the conjugate acid.
On dilution the ration of the concentration terms of the salt and weak acid/base does not change. Hence the pH of the buffer solution does not change.
When acid or base is added to buffer, it resists changes in the pH.
Therefore, option (C) is correct.
Explanation:
it is used to describe those action of adrenal corticosteroids that produce sodium
Answer:
19.4 g of alum, will be its theoretical yield
Explanation:
The reaction is:
2 Al + 2 KOH + 4 H₂SO₄ + 22H₂O → 3H₂ + 2KAl(SO₄)₂•12H₂O
Let's determine the amount of acid.
M are the moles contained in 1 L of solution or it can be mmoles that are contained in 1 mL of solution
M = mmol /mL
M . mL = mmol
We replace: 8.3 mL . 9.9 M = 82.17 mmoles
We convert to moles: 82.17 mmol . 1 mol / 1000mmol = 0.082 moles
Ratio is 4:2
4 moles of sulfuric acid can make 2 moles of alum
By the way, 0.082 moles of acid may produce ( 0.082 . 2) /4 = 0.041085 moles.
We convert moles to mass:
Molar mass of alum is: 473.52 g/mol.
0.041085 moles . 473.52 g/mol = 19.4 g
Answer : The enthalpy change for the reaction is, 201.9 kJ
Explanation :
According to Hess’s law of constant heat summation, the heat absorbed or evolved in a given chemical equation is the same whether the process occurs in one step or several steps.
According to this law, the chemical equation can be treated as ordinary algebraic expression and can be added or subtracted to yield the required equation. That means the enthalpy change of the overall reaction is the sum of the enthalpy changes of the intermediate reactions.
The balanced reaction of will be,
The intermediate balanced chemical reaction will be,
(1)
(2)
(3)
(4)
Now we will multiply the reaction 1 by 2, revere the reaction 2, reverse and half the reaction 3 and 4 then adding all the equations, we get :
(1)
(2)
(3)
(4)
The expression for enthalpy of the reaction will be,
Therefore, the enthalpy change for the reaction is, 201.9 kJ