Answer:
Explanation:
<em>Percent ionization</em> is the percent of the original acid that has ionized:
- %, ionization = (molar concentration of hydrogen ions at equilibrium / molar concentration of original acid) × 100
<u><em>Part A:</em></u>
<u>1) Data:</u>
- Ka: 6.7 × 10 ⁻⁷
- [HA] = 0.10 M
- %, ionization = ?
<u>2) Equilibrium equation:</u>
<u>3) ICE (initial, change, equilbirium) table </u>
Concentrations
HA H⁺ A⁻
Initial 0.10 0 0
Change - x + x + x
Equilibrium 0.10 - x x x
- Equation: Ka = [H⁺] [A⁻] / [HA] =
6.7 × 10 ⁻⁷ = x² / (0.10 - x)
<u>4) Solve the equation:</u>
Since Ka << 1, you can assume x << 0.10 and 0.10 - x ≈ 0.10
- 6.7 × 10 ⁻⁷ ≈ x² / 0.10 ⇒ x² ≈ 6.7 × 10⁻⁸ ⇒ x ≈ 2.588 × 10⁻⁴
- % ionization ≈ (2.588 × 10⁻⁴ M / 0.1 M) × 100 ≈ 0.2588 % ≈ 0.26% (two significant figures)
<u><em>Part B:</em></u>
<u>1) Data:</u>
- Ka: 6.7 × 10 ⁻⁷
- [HA] = 0.010 M
- %, ionization = ?
<u>2) Equilibrium equation:</u>
<u>3) ICE table:</u>
Concentrations
HA H⁺ A⁻
Initial 0.010 0 0
Change - x + x + x
Equilibrium 0.010 - x x x
- Equation: Ka = [H⁺] [A⁻] / [HA] =
6.7 × 10 ⁻⁷ = x² / (0.010 - x)
<u>4) Solve the equation</u>:
Since Ka << 1, you can assume x << 0.010 and 0.010 - x ≈ 0.010
- 6.7 × 10 ⁻⁷ ≈ x² / 0.010 ⇒ x² ≈ 6.7 × 10⁻⁹ ⇒ x ≈ 8.185 × 10⁻5
- % ionization ≈ (8.185 × 10⁻⁵ M / 0.010 M) × 100 ≈ 0.8185 % ≈ 0.82% (two significant figures)
Answer:
C. Its viscosity decreases with increasing temperature
Explanation:
- The liquid Sulphur is a liquid that turs yellowish green. At a temperature of 120 it tends to melt and has a lower viscosity.
The element Bromine is known as the chemical symbol Br2
Answer:
A. = 143
B. = 8
C. =32
Explanation:
Number of neutron = mass number - atomic number