(b) If a water sample considered to be hard water contains 64 mg of CaCO3 per 300 ml of water. Calculate the hardness in terms of MgSO4 equivalent in mg/litre of MgS 04-​

The best evidence that no chemical reaction occurred in the process described is that the sugar is still in the beaker after the water has evaporated. Therefore, the correct answer is C.

The chemical, known as the reactant, is changed into a new substance, the product, during a chemical reaction. Here, the atoms that make up the reactants are rearranged to form products. This is an irreversible process.

In the process described in the question, sugar was simply dissolved in water to form a sugar-water solution. This is a physical change, not a chemical change, because the sugar molecules remained intact and did not undergo a chemical reaction with the water molecules. The sugar molecules were simply dispersed throughout the water, making them invisible to the eye.

When the water evaporated, the sugar molecules were left behind and re-crystallized in the bottom of the beaker. This process did not involve a chemical reaction, only a physical change.

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5. This energy is released with wavelengths and frequencies within the visible portion of the electromagnetic spectrum.

3. The excited state is not a stable configuration for the atom because there are lower energy

sublevels not filled, so e' eventually fall back to original energy levels (ground state)

1. Electrons start in the most stable arrangement, called the ground state

2. Electrons absorb energy from heat or electricity and move to a higher energy level, this is called the excited state

4. When they fall back, the electrons have to release the energy absorbed to

move to the excited state.

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The concentration of I in 0.10 M AgNO, saturated with AgI in the solubility product  is 8.3 x 10^-16 M.

The solubility product expression for AgI is:

Ksp = [Ag+][I-]

At equilibrium, the concentration of Ag+ ions is equal to the solubility of AgI, which is equal to the molar solubility of AgI in 0.10 M AgNO3. Let's assume that the molar solubility of AgI is x. Then, the equilibrium concentrations of Ag+ and I- ions are:

[Ag+] = 0.10 M + x

[I-] = x

The solubility product expression can be written as:

Ksp =[tex]\sqrt{x}[/tex] ([Ag+] * [I-])

Substituting the equilibrium concentrations into the solubility product expression, we get:

Ksp = √(0.10 M + x) * (x)

Using the quadratic equation, we can solve for x:

Ksp =√ 8.3 x 10^-17

0.10 M is much greater than x, so we can assume that (0.10 M + x) ≈ 0.10 M

Ksp = (0.10 M) * (x)

x = Ksp / (0.10 M)

x = 8.3 x 10^-16

So, the molar solubility of AgI is 8.3 x 10^-16 M. Since the concentration of I- ions is equal to the solubility of AgI, the concentration of I- ions is also 8.3 x 10^-16 M.

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The molecular formula of acetylene is C₂H₂ and ethylene is C₂H₄.

The simplest whole-number ratio of the atoms in a compound is shown by empirical formulae, the number of each type of atom in a molecule is shown by molecular formulas, and the bonds between the atoms in a molecule are shown by structural formulas. The empirical formula of naphthalene is C₁₀H₈ and benzene is C₆H₆.

The chemical formula of the reactants and products are:

The balanced reactions are:

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Answer: None of the above

Explanation:

Rules Governing the Allowed Combinations of Quantum Numbers

The principal quantum range (n) can't be zero. The allowed values of n are consequently 1, 2, 3, 4, and so on. The angular quantum quantity (l) can be any integer between zero and n - 1. If n = 3, for example, l can be either 0, 1, or 2.

The set of quantum numbers n=1,l=1,ml=0,ms=+21 is no longer viable for an electron.

So right set of quantum numbers is n=2,l=1,m=0,s=+21.

Solution : The designation `4p` indicates that the orbital has a important quantum number `n = 4` and an angular-momentum quantum wide variety `l = 1`. The magnetic quantum quantity can have any of the values `-1, 0`, or `+1`.

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The empirical formula of decaborane is B5H7.

To find the empirical formula of decaborane, we need to determine the simplest whole-number ratio of atoms in the compound.

The molecular formula of decaborane is B10H14, which means it contains 10 boron atoms and 14 hydrogen atoms.

To determine the simplest ratio of boron to hydrogen atoms, we can divide each by the greatest common factor (GCF) of the two numbers.

The GCF of 10 and 14 is 2, so we divide each by 2:

B10H14 becomes B5H7

Therefore, the empirical formula of decaborane is B5H7 from B10H14

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A Ph.D. or Psy.D. in psychology with a cognitive psychology concentration is normally required to be categorized as a cognitive psychologist. Thus, the choice is between a Ph.D. and a Psy.D.

False. While most cognitive psychologists do their study in academic institutions, some may work in governmental, nonprofit, or commercial organizations.

False. It is not compulsory to pursue a career in cognitive psychology, even though taking part in a Directed Independent Study (DIS) during your undergraduate studies may be advantageous to get research experience in the field. Other options for developing one's research abilities and experience include working in a lab or doing an internship.

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Answer:

A

Refer to pic for explanation

18 moles of oxygen can be produced by decomposing 12 moles of KClO₃.

The balanced chemical equation for the decomposition of KClO₃ is:

2KClO₃ → 2KCl + 3O₂

According to the equation, for every 2 moles of KClO₃ decomposed, 3 moles of O₂ are produced. So, to determine how many moles of O₂ are produced by decomposing 12 moles of KClO₃, we can use the following proportion:

2 moles KClO₃ / 3 moles O₂ = 12 moles KClO₃ / x moles O₂

where x is the number of moles of O₂ produced.

Solving for x, we get:

x = (3 moles O₂)(12 moles KClO₃) / (2 moles KClO₃)

x = 18 moles O₂

Therefore, 12 moles of KClO₃ can produce 18 moles of O₂.

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The pH at the equivalence point for the titration of 0.20 M HCl versus 0.10 M NaOH is 7.0.

The reaction between HCl and NaOH is a strong acid-strong base titration. At the equivalence point, all of the HCl has reacted with an equal amount of NaOH to form water and NaCl.

The balanced equation for the reaction is:

HCl + NaOH → NaCl + H2O

Since the reaction between HCl and NaOH is a 1:1 stoichiometric ratio, we can say that at the equivalence point, the moles of HCl consumed are equal to the moles of NaOH added.

Moles of HCl = concentration of HCl × volume of HCl used

Moles of NaOH = concentration of NaOH × volume of NaOH added

At the equivalence point, Moles of HCl = Moles of NaOH. Therefore,

concentration of HCl × volume of HCl used = concentration of NaOH × volume of NaOH added

Since we have equal volumes of HCl and NaOH at the equivalence point, we can simplify the equation to:

concentration of HCl = concentration of NaOH

Therefore, the concentration of HCl and NaOH at the equivalence point is both 0.15 M (the average of the initial concentrations of 0.20 M HCl and 0.10 M NaOH).

To find the pH at the equivalence point, we can use the equation for the dissociation of water:

H2O ⇌ H+ + OH-

At 25°C, the concentration of water is 55.5 M. At the equivalence point, the concentration of H+ and OH- are both equal, so we can write:

Kw = [H+][OH-]

where Kw is the ion product constant for water, which has a value of 1.0 × 10^-14 at 25°C.

At the equivalence point, the concentration of H+ and OH- are both equal to the concentration of NaOH and HCl, which is 0.15 M.

Therefore:

Kw = [H+][OH-]

1.0 × 10^-14 = [0.15][0.15]

[H+] = [OH-] = sqrt(1.0 × 10^-14) = 1.0 × 10^-7 M

The pH at the equivalence point is equal to the negative logarithm of the H+ concentration:

pH = -log[H+]

pH = -log(1.0 × 10^-7)

pH = 7.0

Therefore, the pH at the equivalence point for the titration of 0.20 M HCl versus 0.10 M NaOH is 7.0.

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Castration is the method of storing milk there was discovered by Louis Pasteur

Explanation:

Castration is the method of storing milk there was discovered by Louis Pasteur

Stoichiometric amounts relate to the proportional amounts of reactants and products in a balanced chemical equation.

What transpires during a chemical reaction to the molecules of the reactants?

Only atoms from the reactants can wind up in the products of a chemical reaction. No atoms are annihilated or made into new ones. To create the products, the reactants come into contact with one another, the bonds between their atoms are broken, and the atoms then rearrange and establish new bonds.

The frequency of collisions between the two reactants will grow as the reactant concentration rises. There are times when collisions don't cause a response (atoms misaligned or insufficient energy, etc.). More collisions and reaction possibilities result from higher concentrations.

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When 43 g of ethyl lactate is burned in excess oxygen gas, 80.098 g of CO2 are formed.

What is Molecular Formula?

A molecular formula represents the actual number and type of atoms that make up a molecule of a compound. It shows the chemical symbols for the different elements in the compound and the subscript numbers that indicate the number of atoms of each element. For example, the molecular formula for water is H2O, which shows that each molecule of water contains two hydrogen atoms (H) and one oxygen atom (O).

First, we need to determine the molecular formula of ethyl lactate. The empirical formula of C5H10O3 has a molecular weight of approximately 118 g/mol (5 * 12.011 g/mol for carbon + 10 * 1.00794 g/mol for hydrogen + 3 * 15.9994 g/mol for oxygen).

To find the molecular formula, we need to know the actual molecular weight of ethyl lactate. We can use the given amount of ethyl lactate (43 g) to calculate the number of moles:

n = m/M = 43 g / 118 g/mol = 0.3644 mol

Now, we need to find the molecular formula. We can do this by dividing the molecular weight (118 g/mol) by the empirical formula weight (which we already calculated as 118 g/mol):

118 g/mol / 118 g/mol = 1

This tells us that the empirical formula is also the molecular formula, so ethyl lactate is C5H10O3.

Now we can use the balanced chemical equation for the combustion of ethyl lactate:

C5H10O3 + 8 O2 → 5 CO2 + 5 H2O

From the equation, we can see that 1 mol of ethyl lactate produces 5 mol of CO2. We already calculated that we have 0.3644 mol of ethyl lactate, so we can use this to find the amount of CO2 produced:

n(CO2) = 5 mol CO2/mol ethyl lactate * 0.3644 mol ethyl lactate = 1.822 mol CO2

Finally, we can convert this to grams of CO2:

m(CO2) = n(CO2) * M(CO2) = 1.822 mol * 44.0095 g/mol = 80.098 g

Therefore, when 43 g of ethyl lactate is burned in excess oxygen gas, 80.098 g of CO2 are formed.

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Answer: C

Explanation: The assumption that pairing of electrons reduces orbital stability is not part of Bohr's theory.

Bohr's theory of atomic structure mainly focuses on the behavior of electrons in the atom and makes several key assumptions:

a) Energy is not dissipated when electrons move in an orbital (postulate of quantization)

b) Electrostatic force balances force tending to throw electron out of orbital (Coulomb's law)

d) Electrons move from one orbital to another by either absorbing or radiating energy (postulate of transitions)

Therefore, the correct answer is option (c) Pairing of electrons reduces orbital stability.

Answer:

269.8

Explanation:

The balanced chemical equation for the reaction between aluminum and hydrochloric acid is:

2 Al + 6 HCl -> 2 AlCl3 + 3 H2

From the equation, we can see that 2 moles of aluminum react with 3 moles of H2 to produce 2 moles of AlCl3. Therefore, the molar ratio of aluminum to hydrogen gas is 2:3.

To find the mass of aluminum required to produce 30 grams of H2, we need to use the molar mass of hydrogen gas and the molar ratio between aluminum and hydrogen gas. The molar mass of hydrogen is approximately 1 g/mol.

First, we need to calculate the number of moles of hydrogen gas produced:

30 g H2 x (1 mol H2/2 g H2) = 15 mol H2

Since the molar ratio of aluminum to hydrogen gas is 2:3, we can calculate the number of moles of aluminum required:

15 mol H2 x (2 mol Al/3 mol H2) = 10 mol Al

Finally, we can calculate the mass of aluminum required:

10 mol Al x (26.98 g Al/mol) = 269.8 g Al

Therefore, approximately 269.8 grams of aluminum are required to produce 30 grams of H2.

Answer:

Explanation:

The balanced chemical equation for the reaction between magnesium carbonate and hydrochloric acid is:

MgCO3 + 2HCl → MgCl2 + H2O + CO2

From the equation, we can see that 1 mole of magnesium carbonate reacts with 2 moles of hydrochloric acid to produce 1 mole of carbon dioxide. The molar mass of magnesium carbonate is 84.3 g/mol, which means that 21 g of magnesium carbonate is equal to 0.25 moles (21/84.3). Therefore, 0.25 moles of magnesium carbonate will react with 0.5 moles of hydrochloric acid to produce 0.25 moles of carbon dioxide.

The volume of carbon dioxide can be calculated using the ideal gas law, which is 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 standard temperature and pressure (STP) of 273 K and 1 atm, we can use the molar volume of a gas at STP, which is 22.4 L/mol, to calculate the volume of carbon dioxide produced.

V = n × 22.4 L/mol

V = 0.25 mol × 22.4 L/mol

V = 5.6 L

Therefore, the volume of carbon dioxide produced when 21 g of magnesium carbonate reacts completely with excess hydrochloric acid is 5.6 L. The answer is option A, 4 dm³, which is approximately equal to 5.6 L.

Answer:

D. Unbalanced forces act on the object

Explanation:

Newton's First Law of Motion states that an object at rest will remain at rest unless acted on by an outside force.

the object will begin to move when unbalanced forces act on it

Explanation:

Newton's first law of motion states that 'a body or an object will continue to be in its state of rest until it's acted upon by an external force'

The 8 anhydrοus salt has a mass οf 178 amu..

A mοle is the atοm's elementary particle, an iοn. The mοle οf the substance is always related tο the Avοgadrο number. The mοle is always assοciated with the weight οr mass οf the element οr substance. The standard unit οf a mοle is mοl. The mοle is a significant factοr οf the reactant and prοducts tο fοrm an equatiοn. A mοle calculates the atοm, iοn, and substance weighs.

The amοunt οf matter in a bοdy is referred tο as its mass. The kilοgrams is the kilοgrams, which is the SI unit οf mass (kg). Mass is defined as: Mass = Density /Vοlume.

mass οf water =45.1%    = 45.1 g

means that 45.1 g οf water in 100 g salt

hence mass οf anhydrοus salt(As)= 100 g  - 45.1 g =  54.9 g

mοlar mass οf anhydrοus salt (As) = 178 amu=178 g /mοl

mοlar mass οf water (H2O)=18.015 g /mοl

1st step:-     Find mοl οf  water

mοl οf water =   mass οf water /  mοlar mass οf water

=   45.1 g / 18.015 g /mοl

=  2.5035 mοl

2nd step:-      find mοl οf Anhydrοus salt

mοl οf  Anhydrοus salt (As) = mass οf anhydrοus salt /     mοlar mass οf anhydrοus salt

=     54.9 g  /  178 g /mοl

=  0.3084 mοl

3rd step:-calculate water οf crysatlisatiοn

=    mοl οf water  /   mοl οf  Anhydrοus salt    

=    2.5035 mοl /  0.3084

=  8.118  

=  8 (apprοx)

hence tοtal 8 mοl οf water present in Anhydrοus salt(As)   = As*8H20

Therefοre, 8 anhydrοus salt has a mass οf 178 amu.

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The grams of zinc chloride produced if .236 grams of zinc react completely is 0.492 grams

The balanced chemical equation for the reaction is:

Zn + 2 HCl → H2 + ZnCl2

The molar mass of Zn is 65.38 g/mol and the molar mass of ZnCl2 is 136.29 g/mol.

To calculate the grams of zinc chloride produced, we first need to find the number of moles of zinc used in the reaction:

moles of Zn = mass of Zn / molar mass of Zn

moles of Zn = 0.236 g / 65.38 g/mol

moles of Zn = 0.00361 mol

From the balanced chemical equation, we can see that the stoichiometric ratio of Zn to ZnCl2 is 1:1. This means that 0.00361 mol of Zn will produce 0.00361 mol of ZnCl2.

To calculate the mass of ZnCl2 produced, we can use the following equation:

mass of ZnCl2 = moles of ZnCl2 x molar mass of ZnCl2

mass of ZnCl2 = 0.00361 mol x 136.29 g/mol

mass of ZnCl2 = 0.492 g

Therefore, if 0.236 grams of zinc react completely, 0.492 grams of zinc chloride will be produced.

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The rate of a reaction is proportional to the some power of the molar concentration of each of the reactants. The order gives us an idea about the kinetics of the reaction.

The order of a reaction is defined as the sum of the powers of the concentration terms of the reactants in the experimentally determined rate equation for the reaction. It is an experimental quantity.

a. The order of the alkene is 1

b. The order of the bromine s 2

c. The overall kinetic order is 3

Since the reaction is third order, the overall rate constant is mol²L⁻²s⁻¹ or M⁻²s⁻¹.

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Answer: Oxygen and glucose are both reactants in the process of cellular respiration. The main product of cellular respiration

The compounds formed are;

1) [tex]CrBr_{3}[/tex]

2) [tex]Fe_{2} O_{3}[/tex]

3)  [tex]((Hg)_2}) _{2} (CO_{3}) _{2}[/tex]

4) [tex]Ca(ClO_{3} )_{2}[/tex]

5)[tex](NH_{4}) _{3} PO_{4}[/tex]

Ionic compounds are formed through a type of chemical bonding called ionic bonding. Ionic bonding occurs when one or more electrons are transferred from one atom to another, resulting in the formation of ions, which are atoms or molecules that have a net electric charge due to a loss or gain of electrons.

The formation of ionic compounds typically occurs between atoms with large differences in electronegativity, or the ability of an atom to attract electrons.

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I used the results from the first part of the experiment to design a marble run by understanding the principles of potential and kinetic energy.

Kinetic energy is the energy of motion. It is the energy an object has due to its motion. When an object is moving, it has kinetic energy. This energy is dependent on the mass of the object and its velocity. Kinetic energy can be calculated by multiplying the mass of the object by the square of its velocity and then dividing the result by two. Kinetic energy is one of the two main types of energy, along with potential energy. It has the ability to cause change within a system, such as breaking chemical bonds. When an object is at rest, it does not have kinetic energy. However, as soon as it begins to move, it acquires kinetic energy. Kinetic energy can be changed or transferred from one object to another, or from one form to another.

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The standard enthalpy change of reaction for the given reaction is -46.9 kJ/mol. Since the enthalpy change is negative, it indicates that the reaction is exothermic and releases energy in the form of heat.

What is Enthalpy?

Enthalpy (H) is a thermodynamic property that describes the total heat content of a system at constant pressure. It is a measure of the internal energy of a system, which includes the energy required to create or destroy the system as well as the energy required to maintain its temperature and pressure.

The standard enthalpy change of reaction (ΔHr0) can be determined using the standard enthalpies of formation (ΔHf0) of the reactants and products.

2HCl(aq) + Ca(OH)2(s) → CaCl2(s) + 2H2O(l)

The standard enthalpy change of reaction can be calculated using the following equation:

ΔHr0 = Σ(nΔHf0(products)) - Σ(nΔHf0(reactants))

ΔHf0(HCl(aq)) = -167.2 kJ/mol

ΔHf0(Ca(OH)2(s)) = -986.1 kJ/mol

ΔHf0(CaCl2(s)) = -795.8 kJ/mol

ΔHf0(H2O(l)) = -285.8 kJ/mol

Substituting the values into the equation, we get:

ΔHr0 = [2(ΔHf0(H2O(l))) + ΔHf0(CaCl2(s))] - [2(ΔHf0(HCl(aq))) + ΔHf0(Ca(OH)2(s))]

ΔHr0 = [2(-285.8 kJ/mol) + (-795.8 kJ/mol)] - [2(-167.2 kJ/mol) + (-986.1 kJ/mol)]

ΔHr0 = (-571.6 kJ/mol - 795.8 kJ/mol) - (-334.4 kJ/mol - 986.1 kJ/mol)

ΔHr0 = -1367.4 kJ/mol + 1320.5 kJ/mol

ΔHr0 = -46.9 kJ/mol

Therefore, the standard enthalpy change of reaction for the given reaction is -46.9 kJ/mol. Since the enthalpy change is negative, it indicates that the reaction is exothermic and releases energy in the form of heat.

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Answer:

0.280 moles

Explanation:

We can convert from grams to moles through molar mass.

Stoichiometry

Stoichiometry is the study of the relationship between quantities of substances. Part of stoichiometry is converting between different quantity measurements such as grams (g) and moles (mols).

One way to convert between g and mols is molar mass. Molar mass is the number of grams in one mole of a substance. Molar mass is a constant that can be found on periodic tables.

Conversion

First, we need to look at a periodic table and find that the molar mass of Argon (Ar) is 39.948 g/mol. To convert between units, set up a multiplication problem where the unwanted units (grams in this case) are in the numerator at one point and then in the denominator. Having the units in opposite positions allows the units to cancel out.

So, there are 0.280 moles of Argon in 11.2 grams. Note that this answer has been rounded according to significant figures rules.

The presence of water droplets on the cool upper portion of the test tube after heating the compound suggests that water molecules are trapped within its crystal structure. If the substance were a real hydrate, heating it would have caused all of the water molecules to evaporate, leaving behind an anhydrous substance.

What do you mean by crystalline compound?

The presence of water droplets on the cool upper portion of the test tube after heating the compound suggests that water molecules are trapped within its crystal structure. If the substance were a real hydrate, heating it would have caused all of the water molecules to evaporate, leaving behind an anhydrous substance.

However, the residue created a yellow-brown solution after being further dissolved in water, which is a certain sign of contaminants. When dissolved in water, true hydrates always produce a clear, colourless solution. Thus, the fact that the residue resulted in a coloured solution implies that the compound had impurities.

Together, the water stains and contaminants in the leftovers indicate that the original substance was not a genuine hydrate, but rather a mixture of the anhydrous substance and water, which may have been non-stoichiometrically trapped inside the crystal lattice or adsorbed onto the surface of the crystals.

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The mass (in grams) of HCN produced when 203.6 g of NH₃ reacts with excess CH₄ and O₂ is 323.4 g

The mass of HCN produced when 203.6 g of NH₃ reacts with excess CH₄ and O₂ can be obtained as follow:

2CH₄(g) + 3O₂(g) + 2NH₃ -> 2HCN(g) + 6H₂O(g)

From the balanced equation above,

34 g of NH₃ reacted to produce 54 g of HCN

Therefore,

203.6 g of NH₃ will react to produce = (203.6 × 54) / 34 = 323.4 g of HCN

Thus, the mass of HCN produced is 323.4 g

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Valence electrons move between atoms in shared orbitals-  correctly describes delocalized valence electrons in a metal

Why are valence electrons important and what do they do?

The outermost or valence shell electrons, known as valence electrons, are crucial because they shed light on an element's chemical characteristics and are the ones that are acquired, lost, or shared during a chemical reaction. In general, when an atom's outermost electron shell is complete, it is at its most stable and least reactive.

The number of valence electrons for neutral elements is the same as the number of the atom's main group. A periodic chart element's column can be used to determine its main group number. For instance, carbon, which belongs to group 4, has four external electrons.

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