When an electron drops from one level to a lower energy level, it emits a quantum of energy. The different mix of energy differences for each atom produces different colours. Each metal gives a characteristic flame emission spectrum.
Answer:
5.7
Explanation:
(C₂H₅)₃NHCl dissociates according to the following equation.
(C₂H₅)₃NHCl ⇒ (C₂H₅)₃NH⁺ + Cl⁻
The molar ratio of (C₂H₅)₃NHCl to (C₂H₅)₃NH⁺ is 1:1. Then, the concentration of (C₂H₅)₃NH⁺ is Ca = 0.166 M.
(C₂H₅)₃NH⁺ is the conjugate acid of (C₂H₅)₃N. Given the Kb of (C₂H₅)₃N, we can calculate Ka for (C₂H₅)₃NH⁺ using the following expression.
Ka × Kb = Kw
Ka = Kw / Kb
Ka = 1.0 × 10⁻¹⁴ / 5.2 × 10⁻⁴
Ka = 1.9 × 10⁻¹¹
(C₂H₅)₃NH⁺ dissociates according to the following equation.
(C₂H₅)₃NH⁺ ⇄ (C₂H₅)₃N + H⁺
We can calculate [H⁺] using the following expression.
[H⁺] = √(Ca × Ka) = √(0.166 × 1.9 × 10⁻¹¹) = 1.8 × 10⁻⁶
The pH is:
pH = -log [H⁺] = -log 1.8 × 10⁻⁶ = 5.7
Answer:
Most similar - Lithium
Least similar - Phosphorus
Explanation:
Rubidium is an element in group 1A of the periodic table. It is a metal and forms an ionic compound with chlorine. The formula of the compound is RbCl.
If we look at the options, Lithium is also a group 1A element and forms an ionic compound with chlorine having the formula LiCl which is very much similar to RbCl chemically.
Phosphorus is a nonmetal. Its compounds with chlorine, PCl3 and PCl5 are covalent and does not resemble RbCl in any way.
Answer:
The pH of a solution is simply a measure of the concentration of hydrogen ions,
H
+
, which you'll often see referred to as hydronium cations,
H
3
O
+
.
More specifically, the pH of the solution is calculated using the negative log base
10
of the concentration of the hydronium cations.
∣
∣
∣
∣
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
a
a
pH
=
−
log
(
[
H
3
O
+
]
)
a
a
∣
∣
−−−−−−−−−−−−−−−−−−−−−−−−
Now, we use the negative log base
10
because the concentration of hydronium cations is usually significantly smaller than
1
.
As you know, every increase in the value of a log function corresponds to one order of magnitude.
Explanation:
Yellow paint has 0.511 % PbCrO4 by mass
Mass of PbCrO4 in 1 kg of paint = (0.511 / 100) * 1 kg = 0.00511 kg = 5.11 g
Moles of PbCrO4 = 5.11 g/ 323.19 g/mol
= 0.0158 moles
Moles of K2CrO4 also = 0.0158 moles
Moles of FeCr2O4 = 0.0158 moles K2CrO4 * (4 mole FeCr2O4 / 8 moles K2CrO4)
= 0.0079 moles
Mass of FeCr2O4 (chromite) = 0.0079 moles * 223.83 g/mol
= 1.77 g
Paint is a colored liquid, liquefiable, or solid mastic composition that transforms into a thin solid film after being applied to a substrate. Most commonly used for protection, coloring, or adding texture. Paints come in a variety of colors and can be made in a variety of ways.
Paint consists of pigments, solvents, resins, and various additives. Pigments give the paint its color. Solvents make application easier. The resin helps dry. Additives range from fillers to antifungal agents. There are hundreds of different natural and synthetic pigments.
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