Answer:
1H2+1O2—>H2O2
Explanation:
Use the integer+1
Please help with this question!
Draw and label a diagram of an electron in an atom taking in energy (being "excited")
from light and then dropping in energy ("relaxing") and emitting light as a color.
A negatively charged core nucleus and one or more orbiting electrons make up an atom. There may be the positively charged, somewhat massive protons and neutrons that make up the nucleus. Atoms are the basic building blocks of stuff.
Explain about the electron in an atom?In a neutral atom, there are exactly as many electrons as protons. The total number of protons and neutrons in the atom's nucleus is equal to the mass number (M) of the atom. The difference between the atomic number and the mass number of the atom (M) is equal to the amount of neutrons (Z).
Absorption is the process by which an atom transitions from its ground state to an excited state by absorbing energy from its environment. After absorbing the energy, the electron advances to a higher energy state. Up the opposite process, called emission, the electron releases the excess energy it had taken in and goes back to its ground state.
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Why do we need to understand that reactions can happen at different speeds depending on the conditions?
We need to understand that reactions can happen at different speeds depending on the conditions to develop methods for production improvement.
The rate of any chemical reaction depends upon the nature of the reacting substances. Under the same conditions , reactions that appear similar have different rates of reaction. Chemical reaction proceeds in different speeds, depend on the various factors such as type of chemical transformation , temperature and other factors. the information about the speed of reaction is useful in large scale production.
Thus, We need to understand that reactions can happen at different speeds depending on the conditions to develop methods for production improvement.
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Can someone help me pls, i have like another 3 questions like this .-.
Answer:
1st box: Potential
2nd box: Electrical
3rd box: Kinetic
Explanation:
(1st box) Potential because the energy is stored and ready to act, which is definitely something desired for a battery.
(2nd box) Chemical, as discussed in the comments
(3rd box) Kinetic because the stored, potential energy is now 'acting' or 'in motion', causing it to be kinetic energy.
Answer:
Batteries store potential chemical energy
That the swith releases it into kinetic energy to light the room.
Explanation:
Energy comes in two main forms:
Kinetic energy which is energy of moving object or motion.2. Potential energy which is energy stored in object to be realesed to make effect. It can be stored in form of
Chemical energy. This can be in fuels or food taken by human body or the battery. Gravitational energy. This is due to the gravity and the force pulling the object from a height. Elastic energy. It is energy stored in rubber bands and spring balances.And there is much more....
Principle of conservation of energy says energy is not created nor destroyed but transferred from and object to another in different forms.
suppose you perform a titration of a monoprotic weak acid and you determine the ph at the equivalence point is 9.21 and the ph at the half-equivalence point is 4.24. what is the pka of the acid? enter your answer numerically.
The pKa of the weak acid, based on the titration results, is 4.24.
Only the half-equivalence pH is needed to answer this.
At the half-equivalence point of the titration, half of the monoprotic acid HA has been neutralized and converted to the appropriate salt. That means that the concentration of the acid [HA] is equal to the concentration of its anion [A⁻]. Now, we can consult the Henderson-Hasselbalch equation:
[tex]pH = pKa + log\frac{[A^{-} ]}{[HA]}[/tex]
Because [A⁻] = [HA], that means that:
[A⁻]/[HA] = 1
log(1) = 0
pH = pKa
So, at the half-equivalence point in the titration of the weak acid the pH value of the solution is equal to the pKa value of the weak acid, so pKa = 4.24
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1. State the general period and group trends among
main-group elements with respect to each of the
following properties:
a. atomic radii
b. first ionization energy
c. electron affinity
d. ionic radii
e. electronegativity
The general period and group trends among the main-group elements with respect to each of the following properties are as follows:
atomic radii - increase down the group; decrease across a periodfirst ionization energy - decrease down the group; increase across a periodelectron affinity - decrease down the group; increase across a periodionic radii - increase down the group; decrease across a periodelectronegativity - decrease down the group; increase across a periodWhat are periodic trends?Periodic trends are the trends followed by the properties of the elements going down a group or across a period in the periodic table.
The properties of elements that show periodic trends include:
a. atomic radii - the size of an atom of an element
b. first ionization energy - the energy required to remove a valence electron
c. electron affinity - the energy required to add an electron to a neutral atom
d. ionic radii - the size of the ion of an element
e. electronegativity - the ability to attract electrons
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which of the following pairs of aqueous solutions will form a precipitate when mixed? a) nh4no3 k2co3 b) hg2(no3)2 nabr c) kcl li3po4 d) agc2h3o2 cu(no3)2 e) none of the above solution pairs will produce a precipitate.
Hg2(NO3)2 NaBr will precipitate when combined in an aqueous solution without a catalyst at room temperature.
What is an aqueous solution?A solution that uses water as the solvent is said to be aqueous. It is frequently represented in chemical equations by adding to the relevant chemical formula.
To represent a solution of table salt, or sodium chloride, in water, the symbol Na+ + Cl can be used.
In an aqueous solution, liquid water acts as the solvent.
In other words, the ions and molecules that make up the solute (dissolved) are surrounded by the water molecules and incorporated into their web of connections.
The dissolved organisms then spread out across the water.
An aqueous solution is, to put it simply, anything that has dissolved in water.
The water sign represents (aq).
A substance that has been dissolved in water is called an aqueous solution.
Therefore, Hg2(NO3)2 NaBr will precipitate when combined in an aqueous solution without a catalyst at room temperature.
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What is the density of an object with a mass of 24.6 g and a volume of 7.5 mL?
The density of an object is 3.52g/cc
What is density ?
The density of a substance indicates how dense it is in a given area. Mass per unit volume is the definition of a material's density. In essence, density is a measurement of how closely stuff is packed. It is a particular physical characteristic of a specific thing. The Greek scientist Archimedes made the discovery of the density principle. If you are familiar with the formula and the relevant units, calculating density is simple. Density is represented by the symbol, alternatively it can be written as the letter D.
d = M/V
d = density
M = mass
V = volume
d = 26.4/7.5 = 3.52g/cc
The density of an object is 3.52g/cc
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How many grams of Cu are obtained by passing a current of 12 A through a solution of CuSO4 for 30 minutes?
The quantity of Cu deposited at the cathode will be 7.117 grams.
Given,
Current (in Amperes) = 12 A
This will be equal to 12 C/s (in coulombs per second).
Therefore the total charge in 30 minutes will be:
Q = 12C/s × 30 min × 60 seconds/minute
=> Q = 21600 C
Now, the number of moles of copper which are plated out (n) will be :
n = Q / z·F
In the half-cell reaction,
the number of electrons ( for Cu ) will be = 2 (Cu 2+)
F, the Faraday's constant = 96,485 per mole
We have already discussed that,
n = Q / z.F
=> n = 21600 / (2×96485)
=> n = 0.112 mol
So, 0.112 mol of Cu will be equal to:
0.112×63.546 = 7.117 g
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I need help with this pls it due tomorrow and I need it please please
Answer: Physical - Color, density, boiling/melting point, magnetism, texture, and odor
Chemical - reactivity, combustibility, color change, and temperature change
Explanation:
Physical properties are changes to a substance that can be reversed and refer to its state at the time. Chemical properties are properties that are observable during or after a chemical reaction and cannot be reversed since the reaction has changed the state of the substance.
Which solution of the following has the lowest freezing point?
A. 40g of KBr dissolved in 200g of water
B. 30g of KBr dissolved in 100g of water
C. 20g of KBr dissolved in 250g of water
D. 10g of KBr dissolved in 100g of water
Pls do reply this answer with proper explanation.
Based on freezing point depression, the solution that has the lowest freezing point is 30g of KBr dissolved in 100g of water; option B.
What is freezing point depression?Freezing point depression is a phenomenon that occurs when a solute is dissolved in a pure solvent such as water.
When a solute is dissolved in a solvent, the freezing point depression is calculated using the formula below:
∆T = i * K * mWhere;
i = number of moles of ions produced
K = mola freezing point depression constant
m = molality
From the data given, i (same salt, KBr) and k are both constants.
Hence, the freezing point depression depends on the molality of the solution.
molality = moles / mass of solvent in Kg
Assuming moles = mass (since salt is the same)
Molality of A = 40 / 0.2 = 200 molal
Molality of B = 30 / 0.1 = 300 molal
Molality of A = 20 / 0.25 = 80 molal
Molality of A = 10 / 0.1 = 100 molal
Hence, solution B will have the highest freezing point depression.
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Which group in the Periodic Table contains elements that are all gases?
1. 11
2. 17
3. 12
4. 18
Answer:
d
Explanation:
the group's name is called noble gases. hence they are all gases.
what is the L W H OF THIS CUBE
Answer:
This is NOT a CUBE..
now Considering that one side of one small block is equal to 1 unit.
Then
Length = 3 units
Width = 3 units
Height = 4 units
Please tell me if this is correct
Length would be 3 units, Height is 4 units, and Width is I want to say 5 or 6 not truly sure
a sample of br2(g) takes 46.0 min to effuse through a membrane. how long would it take the same number of moles of ar(g) to effuse through the same membrane?
From the equation of Graham's law of diffusion of gases, it would take the same number of moles of Ar(g) 23 minutes to effuse through the same membrane.
What factors affect the rate of diffusion of gases?The rate of diffusion or effusion of gases is affected by temperature, concentration, pressure, and the molecular weight of the gas.
The gas law that describes how the molecular weight or vapor density of a gas affects the rate of diffusion is Graham's law of diffusion of gases.
Mathematically, Graha's law of diffusion of gases is given below as follows:
R₁ / R₂ = √(M₂ / M₁) or T₁ / T₂ = √(M₁ / M₂)
where;
R₁ is the rate of diffusion of gas 1
T₁ is the time of diffusion of gas 1
M₁ is the molecular weight of gas 1
R₂ is the rate of diffusion of gas 2
T₂ is the time of diffusion of gas 2
M₂ is the molecular weight of gas 2
Substituting the values in the second equation:
The molecular weight of Br₂ = 160 g/mol
The molecular weight of Ar = 40 g/mol
46 / T₂ = √(160 / 40)
T₂= 46 / 2
T₂ = 23 mins
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(a)one of the alkali metal reacts with oxygen forms solid white substance. when this substance is dissolved in water, the solution gives a positive test for hydrogen peroxide, h2o2. when the solution is tested in a burner flame, a lilac-purple flame is produced. what is the likely identity of the metal? (b) write a balanced chemical equation for the reaction of the white substance with water.
Answer: An ionic bond.
Explanation:An ionic bond is the force of attraction that holds together positive and negative ions. It forms when atoms of a metallic element give up electrons to atoms of a nonmetallic element. Ionic bonds form only between metals and nonmetals
help me out please and thank you
Answer:
Explanation:
nitrogen dioxide and calcium oxidea major component of gasoline is octane . when octane is burned in air, it chemically reacts with oxygen gas to produce carbon dioxide and water . what mass of carbon dioxide is produced by the reaction of of octane?
8.70 g of carbon dioxide are generated by the reaction of octane.
Let's compile all the data in one location since we are aware that we will require a balanced equation with masses and molar masses.
M_r: 32.00 44.01
2C₈H₁₈ + 25O₂ ⟶ 16CO₂ + 18H₂O
m/g: 9.88
(a) Calculate the moles of O₂
n = 9.88 g O₂ ×1 mol O₂ /32.00 g O₂
n = 0.3088 mol O₂.
(b) Calculate the moles of CO₂
(16 mol CO2 to 25 mol O2) is the molar ratio.
n = 0.3088 mol O₂ × (16 mol CO₂/25 mol O₂)
n = 0.1976 mol CO₂
(c) Calculate the mass of CO₂
Mass of CO₂ = 0.1976 mol CO₂ × (44.01 g CO₂/1 mol CO₂)
Mass of CO₂ = 8.70 g CO₂
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Using the table of average bond energies, determine the total bond energy for the reactants in the combustion of ethene: C2H4 + 3 O2 --> 2 CO2 + 2 H2O
Explanation:
Hydrogen bonds with carbon 4 times, carbon bonds with itself once, and oxygen bonds with itself 3 times.
Energy of reactants:
E = 4 * 413 + 347 + 3 * 495
= 3484kJ/mol
Answer:
Energy transferred in = 3484kJ/mol
phosphorus pentachloride, pcl5, a white solid that has a pungent, unpleasant odor, is used as a catalyst for certain organic reactions. calculate the number of moles in 55.7 g of pcl5
We have to calculate the moles of PCl₅ in the given gram. divide the gram by molar mass. the number of moles is 0.267 moles
What is mole?
The mole is the amount of substance of a system which contains as many elementary entities as there are atoms in 0.012 kilogram of carbon 12.
To find out the number of moles using the following formula.
mole = mass/molarmass
The molar mass of the PCl₅ = molar mass of phasphorus+ 5x molar mass of chlorine.
The molar mass of the PCl₅= 208.24 g/mol
mole = 55.7g÷208.24g/mol =0.267 moles
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Mole measure the number of elementary entities of a given substance that are present in a given sample. mass. The number of moles in 55.7 g of PCl₅ is 0.26 mole.
What is mole?The SI unit of amount of substance in chemistry is mole. The mole is used to measure the quantity or amount of substance. We know one mole of any element contains 6.022×10²³ atoms which is also called Avogadro number.
Mathematically,
mole =given mass ÷ molar mass
Molar mass of PCl₅= 208.24 g/mol
Given mass of PCl₅= 55.7 g
Substituting the given values we get
mole =55.7 g ÷208.24 g/mol
number of moles=0.26 mole
Therefore, the number of moles in 55.7 g of PCl₅ is 0.26 mole.
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a solution contains an unknown hazardous chemical. we will call it chemical x. you must determine the concentration in molarity for chemical x in that solution. you know that the solution has 36% by mass of chemical x. you know that the molecular mass of chemical x is 36.46g and you know that the density of the solution is 1.18 g/ml. what is the concentration in molarity for the chemical x in this solution?
The molarity of the chemical X is 11.65 M.
To calculate the molarity (c) of the solution, we need the number of moles (n) of substance X and the volume (V) of the solution. We can assume that we have 100 mL = 0.1 L of the solution. Now we have the volume, and we can use it to calculate the mass (m) of the solution using its density (d = 1.18 g/mL):
d = m/V ⇒ m = d * V
m = 1.18 g/mL * 100 mL
m(solution) = 118 g
From this, we can obtain the mass of substance X using the mass percentage (%w = 36% = 0.36):
m(X) = %w * m(solution)
m(X) = 0.36 * 118 g
m(X) = 42.48 g
Now that we have the mass of X, we divide it by its molar mass (M = 36.46 g/mol) to obtain the number of moles:
n = m/M
n = 42.48 g / 36.46 g/mol = 1.165 mol
Finally, we calculate the molarity of the solution:
c = n/V
c = 1.165 mol / 0.1 L = 11.65 M
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Dr. Peterson does an experiment to research the growth rate of mice. He has two groups of mice. He feeds one group a type of food and adds chemical A, which is supposed to increase growth rate. The other group he feeds the same food without chemical A added. His research shows that chemical A increases growth rate by 30%. He does the experiment 4 times and comes up with the same result each time.
Dr. Peterson concludes that chemical A does increase the growth rate of mice. Is Dr. Peterson's conclusion supported by scientific knowledge?
A. Yes; any study that involves a percentage is based on scientific knowledge.
B. No; scientific knowledge never comes from research or experiments.
C. Yes; his conclusion is supported by evidence from his experiment.
D. No; science cannot be used to research small animals such as mice.
Dr. Peterson performed an experiment in order to research the growth rate of mice. He had two groups of mice and he fed one group a type of food with added chemical which results in increasing the growth rate and fed same group of food to another batch without adding any chemicals. His research conveyed that chemical A increased the growth rate of mice by approximately 30%. He performed the same experiment 4 times and got the same result every time. Dr. Peterson concluded that the chemical A results in increase of growth rate of mice. The Interpretation of Dr. Peterson's experiment was supported by the evidence received from his experiment. Therefore, option C is correct.
In his experiment, Dr. Peterson found out that chemical A results in increasing the growth rate of mice by 30% and to make sure that the result obtained is valid and evidential, he performed the same experiment 4 times. Since every time the experiment was repeated, the result came out to be same, the closing statement from his experimental study can be accepted because they are backed by evidence.
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can some one please answer these chemistry questions
how many moles of permanganate were used? [2] 4. how many moles of iron were required to react with the permanganate? [1] 5. what is the mass of iron present in the initial sample? [1] 6. what is the mass percent of iron in the unknown iron sample? [2] 7. a student performed the experiment and got a higher mass percent than expected. other than human error or machine malfunctions, briefly explain a source of error from the experiment.
According to the balanced chemical equation, 2 moles of potassium permanganate produces 5 moles or oxidizes 5 moles of sulphite to sulphate ions. As a result, there are 0.639 moles of potassium.
In alkaline solution, KMnO4 reduces to green K₂MnO₄: 4 KMnO₄ + 4 KOH 4 K₂MnO₄ + O₂ + 2 H₂O. This reaction exemplifies hydroxide's uncommon role as a reducing agent. Mn₂O₇ is formed when concentrated sulfuric acid is added to potassium permanganate. One mole of KMnO₄ requires 5 moles of electrons in an acidic medium. Multiply equation (1) by 5 and equation (2) by 3 to balance the number of electrons. In an acidic medium, five moles of ferrous oxalate are oxidized by three moles of KMnO₄.
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.
Put the following elements in order, with the element having the most valence electrons at the top of your list and the element with the fewest valence electrons at the bottom.swap_vertAstatine (At)swap_vertArsenic (As)swap_vertCalcium (Ca)swap_vertSodium (Na)swap_vertOxygen (O)swap_vertSilicon (Si)swap_vertAluminum (Al)
answer
1. Neon
2. Astatine
3. oxygen
4. Arsenic
5. Silicone
6. Aluminium
7. Calcium
8. Sodium
which of the following properties is typically used to identify whether a bond is polar, nonpolar, or ionic? a. atomic mass. b. electronegativity. c. atomic radius. d. ionization energy.
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What is the conjugate base of H2BO3- (I am confused because one has - and +. I dont understand which one the answer would be)
The conjugate base of a compound is what this compound will be after donating a H⁺.
The comopund in question is H₂BO₃⁻. After it loses 1 H⁺, it will have one less H atom and its charge decrease by one. Its charge is only with a "-" sign, which means its chargeis 1-. After decreasing by one, the charge becomes 2-.
So, the conjugate base will be HBO₃²⁻
2. a. In general, how do the periodic properties of
the d-block elements compare with those of
the main-group elements?
b. Explain the comparison made in (a).
3. For each main-group element, what is the
relationship between its group number and
the number of valence electrons that the group
members have?
I will give Brainkist
The d block elements differ from the main group elements in the nature of the ions that they form. Also, the group number is related to the number of electrons in the valence sell of an atom.
What are the d block elements?The D block elements are those elements that are found to have d orbitals as the orbitals that has the highest energy in the atom. The d block elements are called the transition metals and they have an incompletely filled d - level.
Owing to the fact that d - level is incompletely filled they do exhibit variable oxidation states and are colored. On the other hand, the main group elements do not exhibit a variable oxidation states and the ions that they form are not colored.
Secondly, for each of the main group elements, the group number shows the number of valence electrons that are present in the outermost shell of the atoms in the elements of the groups.
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a gas reacts with a solid that is present in large chunks, then the reaction is run again with the solid pulverized. how does the increase in the surface area of the solid affect the rate of its reactoi
An increase in the surface area of the solid will increase the rate of the reaction.
The reaction rate will be influenced by the solid's surface area if one of the reactants is solid. This is due to the fact that the two kinds of molecules can only collide at the liquid-solid interface, also known as on the surface of the solid. The reaction rate will rise due to a more significant interaction of the surface areas between the two molecules when the solid is pulverized into a gas. If a reactant has a larger surface area: The other reactant is exposed to more particles. Particles are more likely to collide, which results in more successful collisions per second this will influence the reaction speed to increase.
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Please help How many moles of a gas sample are in 5.0 L container at 215 K and 342 kPa(The gas constant is 8.31 L kPa/mol K) Round your answer to one decimal place and enter the number only with no units.
Answer
1.0 mol
Explanation
Given:
Volume, V = 5.0 L
Temperature, T = 215 K
Pressure, P = 342 kPa
The gas constant, R = 8.31 L kPa/mol K
What to find:
The number of moles of the gas sample.
Step-step-solution:
The number of moles of the gas can be determine using the ideal gas equation formula:
[tex]PV=nRT[/tex]Put the given values into the formula and calculate for n:
[tex]\begin{gathered} 342\times5.0=n\times8.31\times215 \\ 1710=1786.65n \\ \text{Divide both sides by 1786.65} \\ \frac{1710}{1786.65}=\frac{1786.65n}{1786.65} \\ n=0.9571\text{ mol} \\ To\text{ one decimal place,} \\ n=1.0\text{ mol} \end{gathered}[/tex]The number of moles of the gas sample is 1.0 mol.
Sodium and lithium have similar chemical properties. What characteristics of these elements explain why they are chemically similar?.
Sodium and lithium have similar chemical properties because both sodium and lithium have one valence electron
Chemical properties is the characteristics of particular substances that can be observed in a chemical reaction and the valence shell electrons in an atom determine the way it will interact with neighboring atoms and therefore determine its chemical properties and both sodium and lithium have one valence electron they share similar chemical properties and element sodium and lithium belong to group IA of the periodic table and the main characteristics is the a single electron in their outermost shell
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pentaborane-9, bshg; is a colorless, highly reactive liquid that will burst into flame when exposed to oxygen. the reaction is 2bshg(l) 1202(g) sbzos(s) 9hzo(l) calculate the kilojoules of heat released per gram of the compound reacted with oxygen. the standard enthalpy of formation of shg is 73.2 kj mol.
The kilojoules of heat released per gram of the compound reacted with oxygen is -72.052 kj/g
The standard enthalpy of formation is a measure of the strength launched or fed on while one mole of a substance is created under trendy situations from its natural elements. The symbol of the standard enthalpy of formation is ΔH f. = A degree means that it's a fashionable enthalpy change.
Enthalpy of a formation refers to the trade in enthalpy for the formation of one mole of a substance from the maximum solid form of its constituent factors. change in enthalpy is symbolized by means of delta H and the f stands for formation.
Given,
compound ΔH°f
B₅H₉ 73.2
B₂O₃ -1271.94
H₂O -285.83
Balanced chemical equation:-
2B₅H₉ (l) + 12O₂ +(g) => 5B₂O₃ + 9H₂O(l)
From Hess's law
ΔH°min = Σ enthalpies of products - Σ enthalpies of reactants
= 5× (-1271.94) + 9×( -285.83) - 2(73.2) kj/mol
ΔH°min = -9078.59 kj/mol
It is seen that 2 moles of B₅H₉ react with O₂ is -9078.59 kj/mol
For 1 mole = -9078.59 kj/mol/2
= 4539.295 KJ/mol
The energy released per gram = energy released per mol/molar mass of B₅H₉
= 4539.295 kj/mol/63 g/mol
energy released per gram = -72.052 kj/g
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