Answer:
1. [H+] = 1 x 10^-4mol/L
2. [OH-] = 1 x 10^-10mol/L
Explanation:
1. From the question given, the pH is 4.0. We can obtain the value of the value of the hydrogen ion concentration [H+] as follows:
pH = —Log[H+]
4 = —Log[H+]
—4 = Log[H+]
Anti-log of —4
[H+] = 1 x 10^-4mol/L
2. Recall: [H+] x [OH-] = 1 x 10^-14
But [H+] = 1 x 10^-4mol/L
1 x 10^-4 x [OH-] = 1 x 10^-14
Divide both side by 1 x 10^-4mol/L
[OH-] = 1 x 10^-14/1 x 10^-4
[OH-] = 1 x 10^-10mol/L
Question #1
Potasium hydroxide (known)
volume used is 25 ml
Molarity (concentration) = 0.150 M
Moles of KOH used
0.150 × 25/1000 = 0.00375 moles
Sulfuric acid (H2SO4)
volume used = 15.0 ml
unknown concentration
The equation for the reaction is
2KOH (aq)+ H2SO4(aq) = K2SO4(aq) + 2H2O(l)
Thus, the Mole ratio of KOH to H2SO4 is 2:1
Therefore, moles of H2SO4 used will be;
0.00375 × 1/2 = 0.001875 moles
Acid (sulfuric acid) concentration
0.001875 moles × 1000/15
= 0.125 M
Question #2
Hydrogen bromide (acid)
Volume used = 30 ml
Concentration is 0.250 M
Moles of HBr used;
0.25 × 30/1000
= 0.0075 moles
Sodium Hydroxide (base)
Volume used 20 ml
Concentration (unknown)
The equation for the reaction is
NaOH + HBr = NaBr + H2O
The mole ratio of NaOH : HBr is 1 : 1
Therefore, moles of NaOH used;
= 0.0075 moles
NaOH concentration will be
= 0.0075 moles × 1000/20
= 0.375 M
<h2>Answer with Explanation </h2>
The energy transformation involved in heating soup in microwaves occurs due to microwave radiation. The radiant energy which also known as heat energy in the microwave causes the water molecules in the soup to gain kinetic energy. Hence, the molecules collide with each other more often causing the soup to heat up in form of waves that are built within the microwave. This is also the reason it is termed as mircowave due to release of waves.
The correct answer is the second option. <span>Baking soda fizzing in vinegar is an example of a chemical change. This example is a chemical reaction which undergoes a chemical change since new substances are being formed the fizzing of the system represent that gas is being produced by the reaction.</span>
