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
2.28 is the pH of 0.166 M triethylammonium chloride, [tex](C_2H_5)_3NHCl[/tex]. The Kb of triethylamine, [tex](C_2H_5)_3N[/tex], is [tex]5.2 \times 10^{-4}[/tex].
The term "potential of hydrogen" (pH) refers to a solution's acidity or alkalinity. It is a scale from 0 to 14, with 7 representing neutrality. A pH value of 7 or higher suggests alkalinity, whereas one below 7 indicates acidity. Since the pH scale is logarithmic, each number corresponds to a tenfold increase or decrease in acidity or alkalinity. For instance, a pH of 3 solution is ten times more acidic than a pH 4 solution. Similar to this, a pH 10 solution is ten times more alkaline than a pH 9 solution.
[tex](C_2H_5)_3NH^+ (aq) + H_2O (l) \rightarrow (C_2H_5)_3N (aq) + H_3O^+ (aq)[/tex]
Kb = [triethylamine] [[tex]H_3O^+[/tex]] / [triethylammonium chloride]
5.2 x[tex]10^{-4}[/tex] = (x) (x) / (0.166 - x)
x ≈ 5.32 x [tex]10^{-3}[/tex] M.
pH= -log(x)
= -log(5.32 x [tex]10^{-3}[/tex]))
≈ 2.28
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Consider the diagram below.
What does C represent?
A) enthalpy of reaction
B) activation energy
C) activated complex
D) energy of the reactants
Answer:
A) enthalpy of reaction
Explanation:
The region C signifies the enthalpy of reaction.
This diagram is the energy profile of an endothermic reaction. In such reaction, heat is absorbed from the surrounding. At the end of the reaction, the heat of product is lesser than that of the reactants.
Enthalpy changes are heat changes accompanying a physical and chemical change. An enthalpy is the difference between the sum of the heat contents of products and sum of the heat contents of reactants.it is indeed A) enthalpy of reaction
7. All physical forms of water (solid, liquid, and gas) make up the
a. atmosphere.
b. biosphere.
C. hydrosphere.
8. The living portion of the earth is contained within the
a. lithosphere.
b. biosphere.
C. hydrosphere.
9. The correct sequence of layers of the atmosphere from innermost to outermost is
a. troposphere--stratosphere--mesosphere--thermosphere.
b. mesosphere--stratosphere--thermosphere--troposphere.
c. thermosphere--stratosphere--mesosphere--troposphere.
10. Most of Earth's weather occurs in the
a. mesosphere.
b. troposphere.
C. stratosphere.
Answer:
C. Hydrosphere for 7
B. Biosphere for 8
Explanation: I am not sure about the rest of them.
Which of the following is an example of a diatomic molecule?
2H
O2
CH4
H2O
Answer:
O2
Explanation:
Diatomic molecules are molecules that have 2 of either H,N,F,O,I,Cl, or Br. In this case, 2H is not correct because the 2 is in front of the element name. Diatomic molecules will have the two after which means that the molecule has these two elements together.
When 60 mL of 0.22 M NH4Cl is added to 60 mL of 0.22 M NH3, relative to the pH of the 0.10 M NH3 solution the pH of the resulting solution will:____________.
Answer:
Will be more acidic
Explanation:
The equilibrium of NH3 in water is:
NH3(aq) + H2O(l) ⇄ NH4⁺(aq) + OH⁻(aq).
Where equilibrium constant, Kb, is:
Kb = 1.85x10⁻⁵ = [NH4⁺] [OH⁻] / [NH3]
From 0.10M NH3, the reaction will produce X of NH4⁺ and X of OH⁻ and Kb will be:
1.85x10⁻⁵ = [X] [X] / [0.10M]
1.8x10⁻⁶ = X²
X = 1.34x10⁻³ = [OH⁻]
As pOH = -log[OH⁻] = 2.87
And as pH = 14 - pOH
pH of the 0.10M NH3 is 11.13
Now, to find the pH of the NH4Cl and NH3 we need to use H-H equation for bases:
pOH = pKb + log [NH4⁺] / [NH3]
Where pKb is -log Kb = 4.74 and [] are moles of both compounds.
Moles of [NH4⁺] = [NH3] = 60mL, 0.060L*0.22M = 0.0132moles:
pOH = 4.74 + log [0.0132] / [0.0132]
pOH = 4.74
pH = 14 - 4.74 = 9.26
That means the pH of the resulting solution will be more acidic
if u trust urself do it
Study these images.
4 photos of clouds. 1: Sky covered with large, flat layers of blue, grey clouds. 2: A tall, fluffy cloud shaped like an anvil. 3: Round, puffy clouds in a blue sky. 4: Thin, wispy clouds high in the sky.
Which image shows a cumulonimbus cloud?
1
2
3
Answer:
3
Explanation:
I wish you the best, its three or 2
Answer:
2
Explanation:
Edge 2021
plz help answer both will mark brainest
assuming the temperature is held constant, how could you increase the pressure inside a container by a factor of 3
The pressure can be increased by a factor of 3 by decreasing the volume by a factor of 3.
Ideal Gas Equation:Given that the temperature of the system is held constant. So it implies that it is an isothermal process.
Now we know that the ideal gas equation is given by:
PV = nRT
where, P is the pressure
V is the volume
n is the number of moles
R is the gas constant, and
T is the temperature
Assuming n is constant, R is universal as constant, so if T is also constant, then:
PV = constant
So if P becomes 3P. that is the pressure increased by a factor of 3, then V must become V/3, so that: (3P)(V/3) = PV = constant.
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Heterotrophic bacteria obtain food by
1.191 mol N2O3 is put into a 2.00 L flask at 25°C where it decomposes into NO2(g) and NO(g). What is the equilibrium constant (to 4 decimal places) if the reaction mixture contains 0.300 mol NO2 at equilibrium?
Answer:
K = 0.0505
Explanation:
Based on the equilibrium:
N2O3 ⇄ NO2 + NO
K, equilibrium constant, is defined as:
K = [NO2] [NO] / [N2O3]
Where [] are the equilibrium concentration of each species in the mixture.
The initial molarity of N2O3 is:
1.191mol / 2.00L = 0.5955M
In equilibrium, 0.5955M of N2O3 reacts producing X Molar of NO2 and X Molar of NO:
[N2O3] = 0.5955M - X
[NO2] = X
[NO] = X
As equilibrium concentration of NO2 is 0.300mol/2.00L = 0.15M; X = 0.15M:
[N2O3] = 0.5955M - 0.15M = 0.4455M
[NO2] = 0.15M
[NO] = 0.15M
And K is:
K = [0.15M] [0.15M] / [0.4455M]
K = 0.0505
Which are replenished MORE quickly than they are used?
A. energy resources
B. material resources
C. renewable resources
D. nonrenewable resources
Answer:c
Explanation: more expensive so people use nonrenewed energy more.
empirical formula of N4H8O4
Answer:
NH₂O
Explanation:
Given compound:
N₄H₈O₄
Unknown:
The empirical formula of the compound = ?
Solution:
The empirical formula of a compound is its simplest formula. It expresses the composition of a the compound in the simplest whole ratio of atoms of the different elements present in the compound.
For the given compound:
N₄H₈O₄
Number of moles of N = 4
H = 8
O = 4
the highest common factor is 4 and we simply divide through by this number;
N = 1
H = 2
O = 1
So, the empirical formula of compound is NH₂O
You need to make an aqueous solution of 0.243 M iron(III) chloride for an experiment in lab, using a 125 mL volumetric flask. How much solid iron(III) chloride should you add?
Answer:
5 g
Explanation:
From the question, we have,
Molarity of FeIII solution= 0.245 M
Volume of solution = 125 ml
From
number of moles= concentration × volume
We have;
Number of moles= 0.245 M × 125/1000
Number of moles = 0.031 moles
Molar mass of Fe III = 162.5g/moles
Mass of iron III = number of moles× molar mass = 0.031 × 162.5= 5 g
n
A gaseous mixture contains 441.0 Torr H2(g), 387.3 Torr N2(g), and 74.5 Torr Ar(g). Calculate the mole fraction, ????, of each of these gases.
????H2=
????N2=
????Ar=
Answer:
XH₂ = 0.4885
XN₂ = 0.4290
XAr = 0.0825
Explanation:
Step 1: Given data
Partial pressure of H₂ (pH₂): 441.0 TorrPartial pressure of N₂ (pN₂): 387.3 TorrPartial pressure of Ar (pAr): 74.5 TorrStep 2: Calculate the total pressure (P)
The total pressure is equal to the sum of the partial pressures of all the gases.
P = pH₂ + pN₂ + pAr = 441.0 Torr + 387.3 Torr + 74.5 Torr = 902.8 Torr
Step 3: Calculate the mole fraction (X) of each gas
We will use the following expression.
Xi = pi / P
where,
Xi: mole fraction of the gas i
pi: partial pressure of the gas i
P: total pressure
XH₂ = pH₂ / P = 441.0 Torr / 902.8 Torr = 0.4885
XN₂ = pN₂ / P = 387.3 Torr / 902.8 Torr = 0.4290
XAr = pAr / P = 74.5 Torr / 902.8 Torr = 0.0825
You are trying to confirm that your bottle of hydrochloric acid is supposedly 1.0 M, as labeled. You decided to perform a titration with 1.3 M sodium hydroxide and 100 mL of your hydrochloric acid. You expect to use 77 mL of sodium hydroxide to neutralize the acid, but in the experiment it actually took 89.13 mL of NaOH to reach the endpoint. What is the actual concentration of the hydrochloric acid?
Answer:
The actual concentration of the hydrochloric acid is 1.2M
Explanation:
The formula to be used here is that of concentration (popularly used during titration);
CₐVₐ/CbVb =nₐ/nb
where Cₐ is the concentration of acid (supposed to be 1.0 M but unsure)
Vₐ is the volume of acid (100 ml)
Cb is the concentration of base (1.3 M)
Vb is the volume of base (89.13 ml)
nₐ is the volume of acid
nb is the volume of base
The equation for the reaction described in the question is
HCl + NaOH ⇒ NaCl + H₂O
we can see from the above equation the ratio of the number of moles for both the acid and the base is 1:1
Thus;
Cₐ × 100/1.3 × 89.13 =1/1
Cₐ = 1.3 × 89.13/100
Cₐ = 1.2M
The actual concentration of the hydrochloric acid is 1.2M
s the purpose of the CaCl2 drying tube? What chemical reaction is it preventing (please supply a mechanism).
Answer:
See explanation
Explanation:
A drying tube prevents moisture from contaminating the reactants. The drying tube contains CaCl2 a hygroscopic material whose function is to absorb the moisture so that it does not react with the Grignard reagent. Without the desiccating action of CaCl2, moisture will enter the reaction chamber,contaminating the reactants.
If water reacts with the Grignard reagent, an alkane is formed. The mechanism of this reaction is shown in the image attached. R here represents the alkyl moiety of the Grignard reagent.
Which of the following reactions will proceed as drawn below? (Yes or No)
Answer:
i wish i could help but t know either so i wish you luck for an answer once again truly sorry don'
Explanation:
i am sorry but i do not know :(
Nerve Impulses ____.
A. start at the dendrite.
B. are electrical signals.
C. can travel backwards and forwards.
D. are only found in the autonomic nervous system.
Answer:
B. are electrical signals.
What are the properties of gas
Answer:
1) easy compressed
2) fills its container
3) far more space
Explanation:
Q12. What thickness (in cm) is the silicon block (density = 2.13 g/cm3) that is 2.65 cm
wide and long necessary to react with 88.3 g of Cr2O3 by the reaction:
Si (s) + Cr203 (s) → SiO2 (s) + Cr (1)
Answer:
1.63cm
Explanation:
Given parameters:
Density of silicon = 2.13g/cm³
Mass of Cr₂O₃ = 88.3g
Width of the block = 2.65cm
Length of the block = 2.65cm
Unknown:
Thickness of the block = ?
Solution:
Reaction equation:
3Si + 2Cr₂O₃ → 3SiO₂ + 4Cr
Let us find the mass of Si,
So,
Number of moles = [tex]\frac{mass}{molar mass}[/tex]
we find the number of moles of Cr₂O₃ ;
Molar mass of Cr₂O₃ = 2(52) + 3(16) = 152g/mol
Number of moles of Cr₂O₃ = [tex]\frac{88.3}{152}[/tex] = 0.58mole
Then;
we know that;
2 moles of Cr₂O₃ reacted with 3 moles of Cr₂O₃
0.58moles of Cr₂O₃ will react with [tex]\frac{0.58 x 3}{2}[/tex] = 0.87mole
So,
Mass of Si = number of moles x molar mass
molar mass of Si = 28g/mol
Mass of Si = 0.87 x 28 = 24.4g
Since density is the mass per unit volume of a compound;
Mass of Si = density of Si x volume of Si block
Volume of Si block = length x width x thickness = 2.65 x 2.65 x thickness
Volume of Si block = 7.02 x thickness
Mass of Si = 2.13 x 7.02 x thickness
24.4 = 15 x thickness
thickness = [tex]\frac{24.4}{15}[/tex] = 1.63cm
What is the amount of charge on a calcium ion if its neutral atom has lost two valence electrons?
A. 1+
B. 2+
C. 3+
D. 4+
Answer: B
Explanation: a calcium ion has a charge of +2 because it has 2 more protons than electrons giving it a positive charge instead of neutral or negative.
A mixture of cyclopropane gas and oxygen is used as an anesthetic. Cyclopropane contains 85.7% C And 14.3% hydrogen by mass. At 50.0 degrees celcius and .984 atm pressure, 1.56 g cyclopropane has a volume of 1.00L.
Required:
What is the molecular formula of cyclopropane?
Answer:
C₃H₆
Explanation:
We'll begin by calculating the empirical formula for cyclopropane. This is illustrated below:
Carbon (C) = 85.7%
Hydrogen (H) = 14.3%
Divide by their molar mass
C = 85.7/12 = 7.14
H = 14.3/1 = 14.3
Divide by the smallest:
C = 7.14/7.14 = 1
H = 14.3/7.14 = 2
Therefore, the empirical formula for the cyclopropane is CH₂
Next, we shall determine the number of mole of cyclopropane.
This can be obtained as follow:
Temperature (T) = 50 °C = 50 °C + 273 = 323 K
Pressure (P) = 0.984 atm
Volume (V) = 1 L
Gas constant (R) = 0.0821 atm.L/Kmol
Number of mole (n) of cyclopropane =.?
PV = nRT
0.984 × 1 = n × 0.0821 × 323
Divide both side by 0.0821 × 323
n = 0.984 / (0.0821 × 323)
n = 0.0371 mole
Next, we shall determine the molar mass of cyclopropane. This can be obtained as follow:
Number of mole of cyclopropane = 0.0371 mole
Mass of cyclopropane = 1.56 g
Molar mass of cyclopropane =.?
Mole = mass /Molar mass
0.0371 = 1.56/Molar mass
Cross multiply
0.0371 × Molar mass = 1.56
Divide both side by 0.0371
Molar mass = 1.56 /0.0371
Molar mass of cyclopropane = 42.05 g/mol.
Finally, we shall determine the molecular formula for cyclopropane. This can be obtained as follow:
[CH₂]ₙ = 42.05
[12 + (2×1)]ₙ = 42.05
[12 + 2]ₙ = 42.05
14n = 42.05
Divide both side by 14
n = 42.05/ 14
n = 3
Thus,
[CH₂]ₙ => [CH₂]₃ => C₃H₆
Therefore, the molecular formula for cyclopropane is C₃H₆
The molecular formula of cyclopropane ([tex]CH_2[/tex]) is equal to [tex]C_3H_6[/tex]
Given the following data:
Percent mass of cyclopropane = 85.7%Percent mass of hydrogen = 14.3%Temperature = 50.0°C to Kelvin = [tex]273+50=323\;K[/tex]Pressure = 0.984 atm.Mass of cyclopropane = 1.56 grams.Volume of cyclopropane = 1.00 Liter.Scientific data:
Ideal gas constant, R = 0.0821L⋅atm/mol⋅KThe atomic weight of carbon (C) = 12 g/molThe atomic weight of hydrogen (H) = 1 g/molTo determine the molecular formula of cyclopropane:
First of all, we would determine the molar mass and number of moles of cyclopropane by using the ideal gas law equation;
[tex]PV=\frac{M}{MM} RT[/tex]
Where;
P is the pressure.V is the volume.M is the mass of gas.MM is the molar mass of gas.R is the ideal gas constant.T is the temperature.Making MM the subject of formula, we have:
[tex]MM = \frac{MRT}{PV} \\\\MM = \frac{1.56\;\times \;0.0821\times \;323}{0.984\;\times \;1}\\\\MM = \frac{41.3686}{0.984}[/tex]
Molar mass, MM = 42.04 g/mol.
For number of moles:
[tex]Number\;of\;moles = \frac{mass}{molar\;mass}\\\\Number\;of\;moles = \frac{1.56}{42.04}[/tex]
Number of moles = 0.0371 moles
Next, we would determine the empirical formula of cyclopropane:
For carbon (C):
[tex]C = \frac{85.7}{12}[/tex]
Carbon (C) = 7.1417
For hydrogen (H):
[tex]H = \frac{14.3}{1}[/tex]
Hydrogen (H) = 14.3
Simplest whole number ratio:
[tex]C = \frac{7.1417 }{7.1417 } =1[/tex]
[tex]H= \frac{14.3 }{7.1417 } =2[/tex]
Empirical formula of cyclopropane = [tex]CH_2[/tex]
Now, we can determine the molecular formula of cyclopropane:
[tex](CH_2)n = 42.04\\\\(12 + 1\times2)n=42.04\\\\14n=42.04\\\\n=\frac{42.04}{14}[/tex]
n = 3
Molecular formula of cyclopropane ([tex]CH_2[/tex]) = [tex](CH_2)_3 =C_3H_6[/tex]
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What stress causes this type of fault to form? O compression O gravity O tension O shearing
Answer: It’s D
Explanation:
Cuz I said so
Answer: d. Shearing
Explanation:
A sample is found to contain 57.2 % N a H C O 3 NaHCOX3 by mass. What is the mass of NaHCO 3 in 4.25 g of the sample
Answer:
The mass of N a H C O 3 present is 2.431 g
Explanation:
The sample contains 57.2 % N a H C O 3 by mass.
To find the mass of N a H C O 3 in the sample, we need to find what the equivalent of 57.2 %.
Mass of N a H C O 3 = Percentage Composition * Mass of sample
Mass of N a H C O 3 = 57.2 / 100 * 4.25
Mass of N a H C O 3 = 2.431 g
The mass of N a H C O 3 present is 2.431 g
The mass of the compound (NaHCO₃) contained in 4.25 g is 2.431 g.
The given parameters;
percentage composition of the compound, = 57.2%mass of the compound (NaHCO₃) = 4.25The mass of the compound (NaHCO₃) contained in 4.25 g is calculated by the finding its equivalent in the given percent composition as follows;
[tex]mass \ = \frac{57.2}{100} \times 4.25\\\\mass = 2.431 \ g[/tex]
Thus, the mass of the compound (NaHCO₃) contained in 4.25 g is 2.431 g.
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During a solar eclipse, which of the following is true?
HELP
Answer:
The moon blocks the Sun's light from hitting the surface of the earth
Explanation:
Why doesn't chromic acid oxidize tertiary alcohol?
. What is the independent variable? (what scientist changes or makes different)Cory wants to see which cup will keep his coffee hottest. He usually drinks coffee out of a Styrofoam cup but decides to compare it to 3 different types of cups. Cory puts 250 ml of his favorite coffee at 95 degrees Celsius into a Styrofoam cup, a plastic cup, a glass cup, and a paper cup. He measures the temperature change of the coffee after 10 minutes.
Answer: the type of cup
Explanation: the independent variable is what you change in your experiment, to find out the different results, in this experiment the factor that they are changing in order to see which outcome is best, is the type of cup.
For which of the following processes would S° be expected to be most positive? a) O2(g) + 2H2(g) 2H2O(g) b) H2O(l) H2O(s) c) NH3(g) + HCl(g) NH4Cl(g) d) 2NH4NO3(s) 2N2(g) + O2(g) + 4H2O(g) e) N2O4(g) 2NO2(g) 12. Which of the following statements is
Answer:
Explanation:
a) O₂(g) + 2H₂(g) = 2H₂O
b) H₂O(l) = H₂O(s)
c) NH₃(g) + HCl(g) = NH₄Cl(g)
d) 2NH₄NO₃(s) = 2N₂(g) + O₂(g) + 4H₂O(g)
e) N₂O₄(g) = 2NO₂(g)
ΔS is positive when there is increase in disorderliness. It happens when there is increase in volume .
Increase is volume is maximus in the following reaction.
d) 2NH₄NO₃(s) = 2N₂(g) + O₂(g) + 4H₂O(g)
in this reaction solid NH₄NO₃ is changed to 7 x 22.4 L of gases so there is maximum increase in volume . Hence maximum increase in entropy . Hence ΔS is most positive .
Use the Rydberg Equation to calculate the energy in Joules of the transition between n = 7 and n = 3 for the hydrogen atom. Find the frequency in Hz of this transition if the wavelength is 1000nm.
Answer:
The energy of each transition is approximately [tex]1.98\times 10^{-19}\; \rm J[/tex].
The frequency of photons released in such transitions is approximately [tex]3.00\times 10^{14}\; \rm Hz[/tex].
Explanation:
The Rydberg Equation gives the wavelength (in vacuum) of photons released when the electron of a hydrogen atom transitions from one main energy level to a lower one.
Let [tex]\lambda_\text{vac}[/tex] denote the wavelength of the photon released when measured in vacuum.Let [tex]R_\text{H}[/tex] denote the Rydberg constant for hydrogen. [tex]R_\text{H} \approx 1.09678 \times 10^{7}\; \rm m^{-1}[/tex].Let [tex]n_1[/tex] and [tex]n_2[/tex] denote the principal quantum number of the initial and final main energy level of that electron. (Both [tex]n_1\![/tex] and [tex]n_2\![/tex] should be positive integers; [tex]n_1 > n_2[/tex].)The Rydberg Equation gives the following relation:
[tex]\displaystyle \frac{1}{\lambda_\text{vac}} = R_\text{H} \cdot \left(\frac{1}{{n_2}^2}} -\frac{1}{{n_1}^2}\right)[/tex].
Rearrange to obtain and expression for [tex]\lambda_\text{vac}[/tex]:
[tex]\displaystyle \lambda_\text{vac} = \frac{1}{\displaystyle R_\text{H}\cdot \left(\frac{1}{{n_2}^2} - \frac{1}{{n_1}^2}\right)}[/tex].
In this question, [tex]n_1 = 7[/tex] while [tex]n_2 = 3[/tex]. Therefore:
[tex]\begin{aligned} \lambda_\text{vac} &= \frac{1}{\displaystyle R_\text{H}\cdot \left(\frac{1}{{n_2}^2} - \frac{1}{{n_1}^2}\right)} \\ &\approx \frac{1}{\displaystyle 1.09678 \times 10^{7}\; \rm m^{-1} \cdot \left(\frac{1}{3^2} - \frac{1}{7^2}\right)} \approx 1.0 \times 10^{-6}\; \rm m \end{aligned}[/tex].
Note, that [tex]1.0\times 10^{-6}\; \rm m[/tex] is equivalent to [tex]1000\; \rm nm[/tex]. That is: [tex]1.0\times 10^{-6}\; \rm m = 1000\; \rm nm[/tex].
Look up the speed of light in vacuum: [tex]c \approx 3.00\times 10^{8}\; \rm m \cdot s^{-1}[/tex]. Calculate the frequency of this photon:
[tex]\begin{aligned} f &= \frac{c}{\lambda_\text{vac}} \\ &\approx \frac{3.00\times 10^{8}\; \rm m\cdot s^{-1}}{1.0\times 10^{-6}\; \rm m} \approx 3.00 \times 10^{14}\; \rm Hz\end{aligned}[/tex].
Let [tex]h[/tex] represent Planck constant. The energy of a photon of wavelength [tex]f[/tex] would be [tex]E = h \cdot f[/tex].
Look up the Planck constant: [tex]h \approx 6.62607 \times 10^{-34}\; \rm J \cdot s[/tex]. With a frequency of [tex]3.00\times 10^{14}\; \rm Hz[/tex] ([tex]1\; \rm Hz = 1\; \rm s^{-1}[/tex],) the energy of each photon released in this transition would be:
[tex]\begin{aligned}E &= h \cdot f \\ &\approx 6.62607 \times 10^{-34}\; \rm J\cdot s^{-1} \times 3.00 \times 10^{14}\; \rm s^{-1} \\ &\approx 1.98 \times 10^{-19}\; \rm J\end{aligned}[/tex].
The energy of the transition between n = 7 and n = 3 is 1.96 × 10^-19 J while the frequency is 3 × 10^14 Hz.
Using the Rydberg Equation for energy;
ΔE = -RH(1/n^2final - 1/n^2initial)
Given that;
nfinal = 3
ninitial = 7
RH = 2.18 × 10^-18 J
ΔE = - 2.18 × 10^-18(1/3^2 - 1/7^2)
ΔE = - 2.18 × 10^-18(0.11 - 0.02)
ΔE = - 1.96 × 10^-19 J
For the second part;
Since the wavelength is 1000nm, we have;
λ = 1000nm
c = 3 × 10^8 m/s
f = ?
c = λf
f = c/λ
f = 3 × 10^8 m/s/1000 × 10^-9 m
f = 3 × 10^8 m/s/ 1 × 10^-6 m
f = 3 × 10^14 Hz
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What is the molarity of a KCl solution made by diluting 75.0 mL of a 0.200 M solution to a final volume of 100.0 mL?
Answer:
0.150 M
Explanation:
The molarity of the solution can be calculated using the formula;
C1V1 = C2V2
Where; C1 = initial concentration of solution
C2 = final concentration of solution
V1 = volume of initial solution
V2 = volume of final solution
According to this question, C1 = 0.200M, C2 = ?, V1 = 75mL, V2 = 100.0mL
Hence,
C1V1 = C2V2
0.200 × 75 = C2 × 100
15 = 100C2
C2 = 15/100
C2 = 0.150M
Therefore, the molarity of the final KCl solution is 0.150M