Answer:
a. Kw = 1.0 × 10⁻¹⁴
Explanation:
a. Let's consider the self-ionization of water.
2 H₂O(l) ⇄ H₃O⁺(aq) + OH⁻
The ion-product of water (Kw) at 25 °C is:
Kw = [H₃O⁺][OH⁻] = 1.0 × 10⁻¹⁴
c. Considering [H⁺] = [H₃O⁺] = 4.0 × 10⁻⁹ M, the concentration of OH⁻ is:
[OH⁻] = 1.0 × 10⁻¹⁴/[H₃O⁺] = 2.5 × 10⁻⁶ M
b. We can calculate the pOH using the following expression.
pOH = -log [OH⁻] = -log 2.5 × 10⁻⁶ = 5.6
d. We can calculate the pH using the following expression.
pH = -log [H⁺] = -log 4.0 × 10⁻⁹ = 8.4
When [H+] = 4.0 × 10–9 M in water at 25°C, then the [tex]Kw =1.0\times 10^-^1^4.[/tex]
What is dissociation constant?
Kw is the dissociation constant or ionization constant of water.
The self-ionization of water will be
[tex]\rm 2 H_2O(l) = H_3O^+(aq) + OH^-[/tex]
The dissociation constant of the water at 25°C will be
[tex]\rm Kw = [H_3O^+][OH^-] = 1.0 \times 10^-^1^4[/tex]
Thus, the correct option is a. [tex]Kw =1.0\times 10^-^1^4.[/tex]
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What pH scale number represents a neutral.
What pH scale number represents a neutral.
The answer is 7
Calculate the amount of heat, in Joules, needed to raise 34.0g of water from 55.0°C to 76.0*C. The specific heat of water is 4.18 J/gºC.
Answer:
2984.52J
Explanation:
Using the formula: Q = m × c × ∆T
Where;
Q = amount of heat (in Joules)
m = mass (in grams)
c = specific heat capacity (J/g°C)
∆T = change in temperature (°C)
Based on the information provided in the question;
m = 34.0g
c = 4.18 J/gºC.
Initial temperature = 55.0°C
Final temperature = 76.0°C
Hence, Q = m × c × ∆T
Q = 34 × 4.18 × (76 - 55)
Q = 142.12 × 21
Q = 2984.52J
Therefore, 2984.52J is the amount of heat, in Joules, needed to raise 34.0g of the water.
Which is a component of John Dalton’s atomic theory?
The ratio of atoms in a compound is fixed.
The atoms of different elements are the same.
An atom is a small particle of matter that can be broken down.
A reaction can create or destroy atoms as well as rearrange them.
Answer:
i think the answer is b
Explanation:
A 25 cm sample of dilute sulfuric acid contains 0.025 moles of the acid.
What is the hydrogen ion concentration in the solution?
A. 0.2 mol/dm3
B. 0.05 mol/dm3
C. 1.00 mol/dm3
D. 2.00 mol/dm3
Answer:B. 0.05 mol/dm3
Explanation:
The hydrogen ion concentration in the solution is 2 mol/dm³
The correct answer to the question is Option D. 2 mol/dm³
We'll begin by calculating the molarity of the solution.
Volume = 25 cm³ = 25 / 1000 = 0.025 dm3
Mole of H₂SO₄ = 0.025 mol
Molarity of H₂SO₄ =?Molarity = mole / Volume
Molarity of H₂SO₄ = 0.025 / 0.025
Molarity of H₂SO₄ = 1 mol/dm³Finally, we shall determine the concentration of Hydrogen ion in the solution.H₂SO₄(aq) —> 2H⁺(aq) + SO₄²¯(aq)
From the balanced equation above,
1 mole of H₂SO₄ contains 2 moles of H⁺.
Therefore,
1 mol/dm³ H₂SO₄ will also contain 2 mol/dm³ H⁺.
Thus, the concentration of Hydrogen ion in the solution is 2 mol/dm³
The correct answer to the question is Option D. 2 mol/dm³
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What mass of sodium hydroxide will neutralize completely 3.612 moles of HCl?
Answer:
NaOH + HCl = NaCl + H2O
(3.612 moles of HCl) x (1/1) x (39.9971 g/mol) = 144.5 grams
So answer B.
Explanation:
NaOH + HCl = NaCl + H2O
(3.612 moles of HCl) x (1/1) x (39.9971 g/mol) = 144.5 grams
To solve such this we must know the concept of double displacement reaction. Therefore, 144.48g sodium hydroxide will neutralize completely 3.612 moles of HCl.
What is chemical reaction?Chemical reaction is a process in which two or more than two molecules collide in right orientation and energy to form a new chemical compound. The mass of the overall reaction should be conserved. There are so many types of chemical reaction reaction like combination reaction, double displacement reaction.
The balanced reaction is
NaOH + HCl = NaCl + H2O
To neutralize completely 3.612 moles of HCl, 3.612 moles of NaOH is required.
mass of NaOH =Mole× Molar mass of NaOH
mass of NaOH=3.612× 40 g/mol
mass of NaOH=144.48g
Therefore, 144.48g sodium hydroxide will neutralize completely 3.612 moles of HCl.
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Based on periodic trends which atom has a larger ionization energy then calcium Ca?
Answer:
Gallium, Germanium, Arsenic, Selenium, Bromine and Krypton
Explanation:
Based on periodic trends, the atom that has a larger ionization energy than calcium are Gallium, Germanium, Arsenic, Selenium, Bromine and Krypton.
Across the period, the ionization energy increases from left to right.
Ionization energy is the energy required to remove the most loosely held electron within an atom. As you go from left to right, the ionization energy increases rapidly.The elements to the right of Ca will have a higher ionization energy compared to Ca.