The pH of the 1.63 M solution of methylamine is 10.56.
What is the pH of the solution?
The pH of the 1.63 M solution of methylamine is calculated from the equation of the dissociation reaction as follows:
H₃CNH₂ (aq) + H₂O (l) ---> H₃CNH₃ (aq) + OH⁻ (aq)
pKb of H₃CNH₂ = 3.66
Kb of H₃CNH₂ = 10⁻³°⁶⁶ = 2.19 * 10⁻⁴
The [OH¯] is calculated using the Kb expression:
Kb = [OH⁻] * [H⁺] / [HA}
[OH⁻] = [H⁺] = x
Kb = x² / (1.63 - x)
Assuming is x <<< 1.63, x is negligible and the denominator = 1.63
x = √(2.19 * 10⁻⁴ x 10⁻¹¹ * 1.63)
x = 3.57 * 10⁻⁴
pOH = -log (3.57 * 10⁻⁴)
pOH = 3.44
pH = 14 - 3.44
pH = 10.56
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Emilio is describing an ancient law that stated the sun and stars moved around Earth. He states that before Copernicus, everyone believed this law and experimental evidence appeared to support it. Copernicus, however, provided data that showed that Earth orbits the sun.
Which statement describes why Emilio’s description is incorrect?
Emilio reversed the facts.
A law cannot be ancient.
A law cannot be disproved.
Emilio named the incorrect scientist.
The statement that describes why Emilio's description is incorrect is that a law cannot be disproved. Therefore, option C is the correct answer.
Scientific laws are guidelines for how nature will act in specific circumstances, typically expressed as an equation. It can be disproved when a new law emerges. In fact, a law cannot be considered scientific if it cannot be disproved by other's experiments.
For instance, the volume of the gas increases as the gas's temperature rises. We refer to this as a natural law. It was first said that sun and stars revolved around the Earth. But later on, this law was disproved by Copernicus. He stated that Eath revolves around the Sun in its particular orbit.
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when 0.56 grams of CuCl2 react with 0.64 grams of Kl, what is the limiting reactant in the production of iodide?
Answer:
[tex]KI[/tex]Explanation:
Here, we want to get the limiting reactant
The limiting reactant is the reactant that produces less amount of the product
We start by writing the balanced equation of the reaction:
We have this as:
[tex]2CuCl_2\text{ + 4KI }\rightarrow\text{ Cu}_2I_2\text{ + I}_2\text{ + 4KCl}[/tex]The iodide here is the copper (i) iodide
From the question, we have 0.56 g of copper (ii) chloride
We need to get the number of moles of it that reacted
We can get that by dividing the mass by the molar mass of copper (ii) chloride
The molar mass of copper (ii) chloride is 134.45 g
Thus, we have the number of moles as:
[tex]\frac{0.56}{134.45}\text{ = 0.004165 mol}[/tex]From the equation of reaction, 2 moles of copper ii chloride produced 1 mole of the iodide
Thus, the number of moles of the iodide produced by the actual reacting mass would be:
[tex]\frac{0.004165}{2}\text{ = 0.0020825 mol}[/tex]Now, let us get the number of moles produced by Potassium iodide
We can get this by dividing the mass by the molar mass of potassium iodide
The molar mass of potassium iodide is 166 g/mol
Thus, we have the number of moles as:
[tex]\frac{0.64}{166}\text{ = 0.00386}[/tex]From the equation of reaction, 4 moles of KI produced 1 mole of the iodide
Thus:
[tex]\begin{gathered} 0.00386\text{ mol will produce:} \\ \frac{0.00386}{4}\text{ = 0.000965} \end{gathered}[/tex]From what we can see, potassium iodide would give less mass of the copper (i) iodide
This makes potassium iodide the limiting reactant
A radio station emits radiation at à wavelength of 3.10m. What is the station’s frequency in megahertz?
Answer: 96.7072445
Explanation: F = 1/T
Is there any limit to the distance through which diffusion can occur?
Answer
Yes, there is a limit to the distance through which diffusion can occur. This is because diffusion time increases with the square of diffusion distance. Diffusion time is inversely proportional to the diffusion coefficient. hus, if the diffusion distance is small, diffusion happens faster because the particles do not have as far to travel.
How many grams of KClO3 are needed to produce 6.75 Liters of O2 gas measured at 1.3 atm pressure and 298 K?
Answer
29.3171 g KClO₃
Procedure
To solve this question consider the following chemical reaction:
2KClO₃→2KCl+3O₂
Then we will use the ideal gas formula to determine the number of moles present in 6.75 L of oxygen gas.
Data:
V=6.75 L
T= 298 °K
P= 1.3 atm
R= 0.08206 L⋅atm⋅°K⁻¹⋅mol⁻¹
Equation
PV=nRT
Solve for n to get the moles
[tex]n=\frac{PV}{RT}=\frac{1.3\text{ atm }6.75\text{ L mol }\degree\text{K}}{0.08206\text{ L.atm 298}\degree\text{K}}=0.3588\text{ mol O}_2[/tex]Use the stoichiometry of the reaction to convert from moles of oxygen to moles of KClO₃.
[tex]0.3588\text{ mol O}_2\frac{2\text{ mol KClO}_3}{3\text{ mol O}_2}=0.2392\text{ mol KClO}_3[/tex]Finally, convert from moles to grams
[tex]0.2392\text{ mol KClO}_3\frac{122.55\text{ g KClO}_3\text{ }}{1\text{ mol KClO}_3}=\text{ 29.3171 g KClO}_3[/tex]Which atom (magnesium or chlorine) has a higher electronegativity?___________________________(you should also be prepared to answer the question if asked for lower electronegativity)5a. Explain why the atom has a higher electronegativity energy. Include the definition of electronegativity, the trend from the periodic table and the reason the trend exists based subatomic particle
Chlorine has higher electronegativity
Explanations:What is electronegativity of an element?This is the tendency of an element to attract electron to itself. According to the periodic table, the electronegativity of an element increases from the left to the right across the period and decreases top to bottom down the group.
This trend exists due to the electronic configuration of the elements. Chlorine element has 7 valence electron in its outer shell and as such will easily accept an electron to itself to attain its octet configuration compared to magnesium that looses his two valence electrons to other elements in order to attain octet configuration.
The tendency of chlorine atom to attract electron makes it have a higher electronegativity compared to magnesium.
. If you do 4 J of work by pulling on a rubber band, the rubber band releases 12 J of heat (stretching of rubber band causes friction of molecules which releases heat). What is the change in internal energy of the system (the rubber band)?
The change in internal energy of the system is found to be -8joules.
We know that, work done W by the system is taken as negative. Work done on the system is taken as positive.
Heat absorbed Q by the system is taken as positive and heat released by the system is taken as negative.
It is given,
W = +4J (Work done on the system)
Q = -12j (Head released by the system)
Now, we calculate change in Internal energy ΔE of the system by using first Law of thermodynamics,
It says, total change in internal energy is equal to the sum of work done and heat absorbed,
So, we can write,
ΔΕ = Q + w
Putting the values,
ΔΕ = −12+ 4
ΔΕ = -8J
Hence, change in internal energy of the system is -8joules.
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describe the relationship between volume and temperature of an ideal gas
Answer:
Explanation:
Here, we want to describe the relationship between the volume and temperature of an ideal gas
This relationship is defined by Charles' law
From this law, we know that the volume of a given mass of gas is directly proportional to its temperature at a fixed pressure
What this means is that as long as the pressure remains unchanged, when the volume increases, the temperature increases, and when the volume decreases, the temperature decreases
These can be represented by the mathematical formula below:
[tex]\frac{V_1}{T_1}\text{ = }\frac{V_2}{T_2}[/tex]Write the ions present in solution of Pb(C2H3O2)2 .
From the chemical structure of the compound that is clearly shown in the question, the ions that should be in the solution are; lead II ion and the acetate ion.
What are ions?The term ions has to do with the species that have a positive charge or a negative charge. Thus we could define an ion as as a charged specie. The charge could owe to an excess of electrons in which case the charge is negative or due to a deficiency of electrons which gives us a positive charge.
Looking at the compound that is in solution, we can see that the ions that are present are lead II ion and the acetate ion.
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How much heat is needed to change the temperature 7.5° C on water with amass of 125 g? c= 4.18
The equation that gives the heat for a change in temperature is:
[tex]Q=m\cdot c\cdot\Delta T[/tex]Where Q is the heat, m is the mass, c is the specific heat capacity and ΔT is the change in temperature.
So, we can calculate Q by substituting the given values:
[tex]\begin{gathered} \Delta T=7.5\degree C \\ m=125g \\ c=4.18J/(g\degree C) \end{gathered}[/tex]So, we have:
[tex]\begin{gathered} Q=125\cancel{g}\cdot4.18J/(\cancel{g}\cancel{\degree C})\cdot7.5\cancel{°C} \\ Q=125\cdot4.18\cdot7.5J \\ Q=3918.75J\approx3900J \end{gathered}[/tex]So, the heat needed is 3918.75 J or approximately 3900 J.
What volume,expressed in liters,would 432.8 grams of fluorine occupy?
ANSWER
The volume of fluorine is 510.52L
STEP-BY-STEP EXPLANATION:
From the question provided, you were given the mass of fluorine to be 432.8 grams.
Given information
Mass of fluorine = 432.8 grams
To find the volume of Fluorine, we need to find the mole of fluorine from the mole formula
[tex]\text{Mole = }\frac{\text{ reacting mass}}{\text{ molar mass}}[/tex]From the periodic table, the molar mass is 18.99 g/mol
The next thing is to substitute the data into the formula
[tex]\begin{gathered} \text{Mole = }\frac{\text{ 432.8}}{18.99} \\ \text{Mole = }22.79\text{ moles} \end{gathered}[/tex]Since the mole of fluorine is 22.79 moles, then, we can now find the volume of fluorine.
At STP, 1 mole is equivalent to 22.4L
Let the volume of fluorine be x
[tex]\begin{gathered} 1\text{ mole }\rightarrow\text{ 22.4L} \\ 22.79\text{ moles }\rightarrow\text{ xL} \\ \text{Cross multiply} \\ 1\cdot\text{ x = 22.4 }\cdot\text{ 22.79} \\ x\text{ = 510.52L} \end{gathered}[/tex]The volume of fluorine is 510.52L
What is the concentration of a 56.20 mL solution of HBr that is completely titrated by 27.50 mL of a 0.200 M NaOH solution?
The concentration of HBr used in the titration is found to be 0.0978M.
Volume of NaOH used is 27.50ml and it’s molarity used is 0.200M.
Volume of HBr used is 56.20ml.
On comparing molarity of both the solutions, we get the relation
HBr × VHbr = MNaOH × VNaOH
MHBr = 0.200M × 27.50ml /56.20ml
MHBr = 0.0978M.
A colorless, stifling gas called hydrogen bromide is highly dissociated in water and exceedingly soluble in water. In the presence of damp air, it rapidly fumes. Hydrogen bromide gas is a very caustic chemical that, when contacted, can result in serious burns.
To determine the concentration of an identified analyte, titration is a typical laboratory technique for quantitative chemical analysis. A standard solution with a defined concentration and volume is prepared as a reagent, also known as the titrant.
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a student is given two unknown material samples that appear to have similar properties and asked to find out if they are the same material what are some characteristics of each sample should she check to see if they are the same material
Density
Color of flame as they burn if they are flammable
Melting point
Amount of each sample
Color of the material
Answer:
Density, flammable,melting point
Explanation:
Im not 100% sure but the other 2 choices just dont make sense
- For one of the valence electrons in the Helium atom, do you think the pull on that electron would be greater than,
less than, or equal to the pull on the Hydrogen atom's valence electron? Use Coulomb's law to support your
answer.
The Hydrogen atom's valence electron Fluorine attracts electrons better than any other element.
The more electronegative atom pulls the bond electrons harder so the shared electrons spend more than half of the time on the more electronegative atom, giving it a partial negative charge. For example, in water O is more electronegative than H and thus has a partial negative charge.
The higher the ionization energy the stronger the attraction between the nucleus and the valence electrons requiring more energy to remove the valences. electronic. The further away the electron is from the nucleus the more likely it is to be ejected. In other words, ionization energy is a function of atomic radius. The larger the radius the smaller the amount of energy required to remove an electron from the outermost orbital.
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Neon has three stable nautrally occurring isotopes. The isotopic mass and percent abundance of these isotopes are given inthe table.Isotope20 Ne21 Ne22 NeIsotopic mass (u)19.9920.9921.99Abundance (%)90.480.2279.25Calculate the average atomic mass of neon.
To calculate the average mass of Ne (neon), we have to use this formula:
[tex]\text{Average atomic mass = }\frac{\sum ^{}_{}(\text{mass of isotopes)x(abundance \%)}}{100}[/tex][tex]\begin{gathered} \text{Average atomic mass = }\frac{(19.99ux90.48+20.99ux0.27\text{ +}21.99ux9.25)}{100} \\ \text{Average atomic mass = }20.18\text{ u} \end{gathered}[/tex]The average atomic mass of Ne = 20.18 u
When do an ice cube and warm soda reach thermal equilibrium?
Water, table salt, and tin metal are all pure substances. Which of these pure substances are compounds
Answer:
water and salt are compounds, water is H2O and table salt is NaCl.
tin is just a metal, an element, not a compound.
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What is ph of .530 M solution of carbonic acid that has acid dissociation of 4.4 x 10^-7
Answer
pH = 3.32
Explanation
Given
Acid dissociation of carbonic acid (Ka) = 4.4x10^-7
Concentration = 0.530 M
Solution
The carbonic acid dissociates into:
[tex]\begin{gathered} H_2CO_3\rightarrow\text{ H}^{+\text{ }}+\text{ HCO3}^- \\ \end{gathered}[/tex][tex]\begin{gathered} Ka\text{ = }\frac{[H^+][A^-]}{[HA]} \\ [H^+]\text{ = \lbrack A}^-] \\ Ka\text{ x \lbrack HA\rbrack= \lbrack H}^+]^2 \\ 4.4\text{ x 10}^{-7}\text{ x 0.530 = \lbrack H}^+]^2 \\ 2.332\text{ x 10}^{-7}\text{ = \lbrack H}^+]^2 \\ 4.816\text{ x 10}^{-4}\text{ = \lbrack H}^+] \\ \\ \end{gathered}[/tex]Now we can calculate the pH
pH = -log[H+]
pH = -log[4.816x10^-4]
pH = 3.32
The lithium-iodine battery is used in pacemakers to generate small electrical impulses that trigger the heart to beat according to the following equation. Identify
the species oxidized.
2 Li(s) + I2 (s) → 2 Lil(aq)
Answer:
The species that oxidizes is lithium, or Li
Explanation:
Since I2 is know to be a halogen, and halogens are oxidizers, iodine is probably not the species being oxidized. So, Li is being oxidized.
Another way to look at the problem is to assign oxidation numbers to all elements on the right and left
The left:
lithium = 0
iodine = 0
Both are 0 since they are in their most stable elemental states
The right:
lithium : +1
Iodine: -1
When something looses an electron and becomes more positive, it is oxidized. Lithium goes from 0 to 1, clearly displaying a rise in oxidization state. So, lithium is being oxidized.
what is the concentration mass divided by volume percent of a solution prepared from 50 g in HCl and 2.5 L of water
The concentration mass by volume percent of a solution is 2 %
What is mass by volume percent of a solution ?
The ratio of the mass of the solute present in a solution to the volume of the solution as a whole is known as the mass/volume percent. The given proportion must be multiplied by 100 because this type of concentration is expressed as a percentage, as shown below.
Mass/Volume Percent is calculated as follows:
mass (solute(g)) / Volume(solution(mL) x 100
Given that:-
Mass of solute =50g
Volume of solution =2.5L = 2500mL
As we know that, mass by volume percentage of the solution is given by-
Mass by volume %= mass of solute/Volume of solution *100
= 50/2500*100 = 2 %
The concentration mass by volume percent of a solution is 2 %
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Cells can regulate different processes in two ways. They can turn on and off the genes that make enzymes, or they can Question 16 options: A) decrease the amount of energy needed to carry out the preferred process. B) increase the activation energy of a reaction. C) regulate the enzymes that are already made. D) increase the amount of energy needed to carry out the preferred process.
In the process of metabolic regulation, cells can turn on and off the genes that make enzymes, or they can regulate the enzymes that are already made; option C.
What is the mechanism of regulation of metabolic processes that cells employ?Metabolic processes are the processes by which the cell carries out its activities.
There are types of metabolic activities that occur in the cells:
catabolism, and anabolismCatabolism is the metabolic process in cells by which large molecules are broken down to release energy required by the body to carry out other cellular actities. An example of catabolism is glycolysis.
Anabolism - this is a metabolic process in cells where energy is used to produce large molecules from the small molecules present in the cells. An example of catabolism is protein synthesis from amino acids.
The cells need to regulate these two processes and this is known as metabolic regulation.
The cells regulate these processes at the gene level that produces the enzyme that catalyzes these processes or by regulating the activity of the enzymes.
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The energy stored in the chemical bonds of a carbohydrate molecule isA. specific heat. B. Kinetic energy. C. potential energy. D. worked.
Answer
C. Potential energy
Explanation
A carbohydrate molecule has chemical bonds, Potential energy is available between chemical bonds.
Relate reactivity to electron distance from nucleus/strength of all attraction to nucleus
Question: Relate reactivity to electron distance from nucleus/strength of all attraction to nucleus
In this instance, it is safe to think of the size of an atom with the electron and nucleus position.
• The larger atom ( more electons ) the more reactive. the larger the atom will also be further from the nucleus and therefore further from the positively charged nucleus.
• Therefore, in terms of attraction, it will be easier for the valence electrons to leave the atom and form ionic bond /interact with another atom to form covalent bond .
In conclusion, reactivity of an element is related to changes in the electronic structure which is strongly dependent upon the attraction of valence electrons to the nucleus.
Convert 62.00nm/s to pm/ms
62.00 nanometres per second is equivalent to 62 picometre per milliseconds
How to convert picometers to nanometres?Picometers is a SI unit of length equal to 10−¹² meters with a symbol pm while nanometres is another SI subunit of length equal to 10-⁹ metres with symbol nm.
The conversion factor of picometers and nanometres is as follows:
1 picometre = 0.001 nanometre
This means that 62 nanometre will be equal to 62000 picometres.
1 second = 1000 milliseconds
62000/1000 = 62 pm/ms.
Therefore, it can be said that 62.00nm/s is the same as 62 pm/ms based on the conversion factor above.
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The 14.7 g sample of graphite takes up a volume of 6.6 cm^3. What is the density of graphite?
The density of graphite that has a volume of 6.6cm³ and a mass of 14.7g is 2.23g/cm³.
How to calculate density?Density is the measure of the mass of matter contained by a unit volume.
The density of a substance can be calculated by dividing the mass of the substance by its volume as follows:
Density = mass ÷ volume
According to this question, graphite has a volume of 6.6cm³ and a mass of 14.7g. The density of this substance can be calculated as follows:
Density = 14.7g ÷ 6.6cm³
Density = 2.23g/cm³
Therefore, 2.23g/cm³ is the density of the graphite.
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Can you label the important processes in the water cycle?
The important processes of the water cycle are:
evaporation,condensation, andprecipitationWhat is the water cycle?The water cycle refers to the processes by which water is replenished or renewed in the environment.
There are three processes in the water cycle, and they are:
evaporation - this is the process by which water molecules in liquid form are converted to water vapor.condensation - this is the process by which water vapor molecules in the atmosphere come together to form clouds.precipitation- this is the process by which the water molecules in the cloud precipitate as either rain, snow, or ice.Learn more about the water cycle at: https://brainly.com/question/28396050
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How many grams of hydrofluoric acid are formed when 173.63 grams of hydrogen (H2) react with 173.63 grams of fluorine (F2):
H2 + F2 rightwards arrow 2HF
The amount, in grams, of hydrofluoric acid that will be formed when 173.63 grams of hydrogen reacts with 173,63 grams of fluorine would be 182.8 grams.
Stoichiometric problemThe balanced equation of the reaction is written as:
[tex]H_2 + F_2 -- > 2HF[/tex]
According to the equation, the mole ratio of hydrogen and fluorine that react to produce hydrofluoric acid is 1:1.
Recall that: mole of substance = mass of the substance/molar mass
Molar mass of [tex]H_2[/tex] = 1x2 = 2 g/mol
Molar mass of [tex]F_2[/tex] = 19x2 = 38 g/mol
Mole of 173.63 grams [tex]H_2[/tex] = 173.63/2
= 86.82 moles
Mole of 173.63 grams [tex]F_2[/tex] = 173.63/38
= 4.57 moles.
Considering the mole ratio of the two reactants, it appears that fluorine is limited in availability and will, therefore, determine the amount of hydrofluoric acid that will be produced.
Mole ratio of fluorine to hydrofluoric acid = 1:2.
Equivalent mole of hydrofluoric acid = 4.57 x 2 = 9.14 moles.
Mass of 9.14 moles HF = 9.14 x 20
= 182.8 grams
Thus, the amount of hydrofluoric acid formed from the reaction is 182.8 grams.
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(4.3) Congratulations, you've been hired by the Chemistry Department to prepare the chemicals
for G-Chem Lab. This week, 4.2 L of a 0.74 M HCl solution is needed. When you go to the
stockroom, you can only find a 4 L bottle of concentrated HCI solution which is 37% by mass HCI
and has a density of 1.1786 g/mL.
a. Calculate the molarity of HCI in the concentrated HCI solution. (Hint: Assume 1 L of
solution.)
b.
Calculate the volume (in mL) of the concentrated solution you'll need to dilute to prepare
the required solution for this week's lab.
Morality is the body of rules that enables individuals to coexist peacefully in groups. In order to act morally, people may have to sacrifice their own immediate interests in order to further society. It is what societies deem to be "acceptable" and "proper.
Explain molarity of HCI in the concentrated HCI solution?The standard by which society determines whether behaviour is appropriate and inappropriate is morality. Morality is demonstrated by the conviction that it is immoral to take something that is not theirs, even if no one would notice.
Hydrochloric acid is a colourless solution of hydrogen chloride (HCl) in water. Concentrated HCl is a particularly corrosive acid with several industrial uses. The pH levels of swimming pools are changed using this material, which is usually referred to as "muriatic acid" in this context, to make them safe to use and to disinfect the water.
Molarity is defined in terms of the volume of the solution, NOT the volume of water. Inaccurate = 5.0 The solution is humour.
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Which of the following equations represents photosynthesis?
a. 6H2O + 6O2 → C6H12O6 + 6CO2
b. C6H12O6 + 6O2 → 6CO2 + 6H2O
c. 6CO2 + 6H2O → C6H12O6 + 6O2
d. 6CO2 + 6O2 → C6H12O6 + 6H2O
e. C6H12O6 + 6CO2 → 6O2 + 6H2O
What does the author describe in this passage?
The author describes different types of t-shirts.
The author describes reasons for moving to New York City.
The author describes two types of energy.
The author describes the dangers of riding in taxis.
The author describes about two types of energy, in this passage which is motion energy and heat energy.
What are motion energy and heat energy?The energy that results from the movement of atoms and molecules within a substance is known as thermal energy, also known as heat energy. These particles generate more heat as they move more quickly. The thermal energy of the earth is referred to as geothermal energy.
Motion energy is energy that is held in the motion of objects. More energy is stored as they move faster. Energy is required to start an object moving, and energy is released when an object slows down. Motion energy includes things like the wind. A car crash is a dramatic example of motion energy; the vehicle comes to a complete stop and abruptly and uncontrollably releases all of its motion energy.
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