Answer:
S = 6.40 × 10⁻⁷ M
Explanation:
In order to calculate the solubility (S) of M(OH)₂ in pure water we will use an ICE Chart. We recognize 3 stages: Initial, Change and Equilibrium, and we complete each row with the concentration or change in concentration.
M(OH)₂(s) ⇄ M²⁺(aq) + 2 OH⁻(aq)
I 0 0
C +S +2S
E S 2S
The solubility product (Kps) is:
Kps = 1.05 × 10⁻¹⁸ = [M²⁺].[OH⁻]²=S.(2S)²
1.05 × 10⁻¹⁸ = 4S³
S = 6.40 × 10⁻⁷ M
Answer:
6
Explanation:
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Answer: The property which depends on the quantity of the substance is called an extensive property. The free energy change for a reaction (Δ G) depends on the quantity of the substance and is therefore an extensive property. It shows the additive nature. The extensive property Δ G is easily calculated from the formula, ΔG = -nFE cell.
Explanation:
An extensive property is one that changes when the size of the sample changes. One such property that can be calculated is enthalpy. Enthalpy can be calculated using the formula H = E + PV.
An extensive property is a property that changes when the size of the sample changes. Examples include mass, volume, length, and total charge. One extensive property that can be calculated is enthalpy.
The enthalpy of a system can be calculated using the formula H = E + PV, where H represents the enthalpy, E the internal energy of the system, P the pressure, and V the volume. Like other extensive properties, the enthalpy of a system would change with the quantity or size of the sample.
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Answer:
a) Moles of iodine molecules = 0.0748 moles of Iodine molecules
b) Moles of iodine atoms = 0.150 moles of iodine atoms
c) Number of iodine atoms = 9.03 * 10²² atoms
d) Number of iodine molecules = 4.50 * 10²² molecules
Note: The complete question is found in the attachment below.
Explanation:
a. Number of moles of iodine molecules in 19.0 g of I₂
Molar mass of iodine molecule = 2 * 127 g/mol = 254g/mol
Number of moles = mass / molar mass
Number of moles = 19.0 g / 254 g/mol
Moles of iodine molecules = 0.0748 moles of Iodine molecules
b) Number of moles of iodine atoms
I mole of iodine molecules contains 2 moles of iodine atoms
Therefore, 0.0748 moles of iodine molecules will contain 2 * 0.0748 moles of iodine atoms
Moles of iodine atoms = 0.150 moles of iodine atoms
c) Number of iodine atoms = number of moles of iodine atoms * 6.02 * 10²³
Number of iodine atoms = 0.150 * 6.02 * 10²³
Number of iodine atoms = 9.03 * 10²² atoms
d) Number of iodine molecules = number of moles of iodine molecules * 6.02 * 10²³
Number of iodine molecules = 0.0748 * 6.02 * 10²³
Number of iodine molecules = 4.50 * 10²² molecules
Complete question is;
What is the frequency of light emitted when the electron in a hydrogen atom undergoes a transition from energy level n=6 to level n=3?
Answer:
Frequency = 2.742 × 10^(14) s^(-1)
Explanation:
First of all, the energy of hydrogen electron from online values is;
E_n = -2.18 × 10^(-18) × (1/n²) J
n is the principal quantum number
We are told that hydrogen atom undergoes a transition from energy levels n = 3 to n = 6.
Thus, it means we have to find the difference between the electrons energy in the energy levels n = 3 to n = 6.
Thus;
E_n = E_6 - E_3
Thus;
E_n = [-2.18 × 10^(-18) × (1/6²)] - [-2.18 × 10^(-18) × (1/3²)]
E_n = (2.18 × 10^(-18)) × [-1/36 + 1/9]
E_n = 0.1817 × 10^(-18) J
From Planck expression, we can find the frequency. Thus;
E = hf
Where h is Planck's constant = 6.626 × 10^(-34) m²kg/s
Thus;
0.1817 × 10^(-18) = 6.626 × 10^(-34) × f
f = (0.1817 × 10^(-18))/(6.626 × 10^(-34))
f = 2.742 × 10^(14) s^(-1)
The frequency of light emitted during an electron transition in a hydrogen atom is determined by calculating the energy difference between the two energy levels and then using this to calculate the frequency using the equation for energy of a photon.
The frequency of light emitted during a transition of an electron in a hydrogen atom can be calculated using the formula for the energy difference (∆E) between two energy levels n1 and n2 in the hydrogen energy level diagram.
The formula to calculate energy difference is: ∆E = E(n2) - E(n1) where E(n) represents the energy of an energy level n. The energy difference ∆E is negative when an electron goes down an energy level (i.e., emits a photon), as the energy level n1 is greater than n2.
The frequency of the emitted photon (∆E) is then given by the formula ∆E = hf where h is Planck's constant (6.63 x 10^-34 Joule seconds) and f is the frequency. Therefore, you can rearrange the equation to find the frequency: f = ∆E / h.
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Answer:
The ballance half reactions are:
Mg²⁺ + 2e⁻ → Mg
6OH⁻ + Si → SiO₃²⁻ + 4e⁻ + 3 H₂O
Coefficients for H2O and OH– are 3 for H₂O (in products side) and 6 for OH⁻ (in reactants side)
Explanation:
Si (s) + Mg(OH)₂ (s) → Mg (s) + SiO₃²⁻ (aq)
Let's see the oxidations number.
As any element in ground state, we know that oxidation state is 0, so Si in reactants and Mg in products, have 0.
Mg in reactants, acts with +2, so the oxidation number has decreased.
This is the reduction, so it has gained electrons.
Si in reactants acts with 0 so in products we find it with +4. The oxidation number increased it, so this is oxidation. The element has lost electrons.
Let's take a look to half reactions:
Mg²⁺ + 2e⁻ → Mg
Si → SiO₃²⁻ + 4e⁻
In basic medium, we have to add water, as the same amount of oxygen we have, IN THE SAME SIDE. We have 3 oxygens in products, so we add 3 H₂O and in the opposite site we can add OH⁻, to balance the hydrogen. The half reaciton will be:
6OH⁻ + Si → SiO₃²⁻ + 4e⁻ + 3 H₂O
If we want to ballance the main reaction we have to multiply (x2) the half reaction of oxidation. So the electrons can be ballanced.
2Mg²⁺ + 4e⁻ → 2Mg
Now, that they are ballanced we can sum the half reactions:
2Mg²⁺ + 4e⁻ → 2Mg
6OH⁻ + Si → SiO₃²⁻ + 4e⁻ + 3 H₂O
2Mg²⁺ + 4e⁻ + 6OH⁻ + Si → 2Mg + SiO₃²⁻ + 4e⁻ + 3 H₂O
Answer:
pH of Buffer Solution 5.69
Explanation:
Mole of anhydrous sodium acetate =
=
= 0.18 mole
100 ml of 0.2 molar acetic acid means
= M x V
= 0.2 x 100
= 20 mmol
= 0.02 mole
Using Henderson equation to find pH of Buffer solution
pH = pKa + log
= 4.74 + log
= 4.74 + log 9
= 5.69
So pH of the Buffer solution = 5.69