Answer:
7.4 - 5.4.
Explanation:
The relationship between HIn that is the non-ionized form and the In^-; the ionized form is an equilibrium Reaction which is given below;
HIn(aq) + H2O(l) <--------> H3O^+(aq). + In^-(aq).
From the question, we are given that the ka is 4 ×10^−7, therefore, the mathematical relationship between HIn and In^- is given below;
Ka = [H3O^+] [In^-] / [HIn] = 4 ×10^−7.
The formula we are going to be using to solve this question is given below;
pH = pKa (+ or -) 1.
Recall that the relationship between the ka and pKa;
pKa = - log (ka).
pKa = - log ( 4 ×10^−7).
pKa = 6.4
Therefore, for it to have a distinct color change, the pH range will be;
pH = pKa (+ or -) 1.
pH= 6.4 + 1 = 7.4.
pH= 6.4 - 1 = 5.4.
Hence, the pH range = 7.4 - 5.4.
Answer:
B
Explanation:
This is because exothermic reactions occurs when bnds are formed, and involves the release of energy.
Endothermic reaction occur when bonds are broken,and involves absorption of energy.
Answer:It would never stop until something hit the ball, to slow it down.
Explanation:
This is so because there is no gravitational pull in space.
Answer:
7.5 L of the 10% and 22.5 L of the 30% acid solution, she should mix.
Explanation:
Let the volume of 10% acid solution used to make the mixture = x L
So, the volume of 30% acid solution used to make the mixture = y L
Total volume of the mixture = <u>x + y = 30 L .................. (1)
</u>
For 10% acid solution:
C₁ = 10% , V₁ = x L
For 30% acid solution :
C₂ = 30% , V₂ = y L
For the resultant solution of sulfuric acid:
C₃ = 25% , V₃ = 30 L
Using
C₁V₁ + C₂V₂ = C₃V₃
10×x + 30×y = 25×30
So,
<u>x + 3y = 75 .................. (2)
</u>
Solving 1 and 2 we get,
<u>x = 7.5 L
</u>
<u>y = 22.5 L</u>
