Cdse quantum dots that are 2. 5 nm in diameter emit blue light upon stimulation. Assuming that the dot is a perfect sphere and that the empty space in the dot can be neglected, calculate how many cd atoms are in one quantum dot of this size.

The element which is likely to have a high thermal conductivity among given options is sodium.

Thermal conductivity of any substance is define as the capability of the substance to carry heat or transfer of heat.

As we know that metals are the good conductors of heat and non-metals are bad conductors, so we exclude carbon, antimony and chlorine atom from this group as they are non-metals. And sodium atom has the thermal capability.

Hence option (4) is correct.

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Answer: Option (4) is correct

Explanation:

Under all temperatures the reaction occurs spontaneously. Option D is correct.

A reaction occurs spontaneously when the Gibbs free energy change of the system is negative, which implies a decrease in the system's free energy.

The following equation expresses the relationship between Gibbs free energy, enthalpy, and entropy:

ΔG∘=ΔH∘−TΔS∘

where ΔG∘ is the change in Gibbs free energy,

ΔH∘ is the change in enthalpy,

T is the temperature in kelvin,

and ΔS∘ is the change in entropy.

The Gibbs free energy change, enthalpy change, and entropy change all have a positive value for a spontaneous reaction.ΔS∘ is positive and ΔH∘ is negative in this specific reaction. This means that the temperature at which the reaction will occur spontaneously is all temperatures.

Therefore, we can say that this reaction is spontaneous at all temperatures.

To determine whether a reaction is spontaneous or nonspontaneous, the Gibbs free energy change (ΔG) must be calculated, and the sign of ΔG indicates the spontaneity. If ΔG is negative, the reaction is spontaneous; if ΔG is positive, the reaction is nonspontaneous, and if ΔG is zero, the reaction is at equilibrium.

Therefore, Option D is correct.

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Answer:

117-

Explanation:

We know that the atomic number of platina is 78 and the atomic average mass number is about 195. Neutron = 195 – 78 = 117. Therefore, a platinum atom has one hundred seventeen neutrons. Based on the atomic number, mass number, and neutron number of the element, three things can be considered.

Hope this helped.

The molecular formula of the compound is PCl₃ if the molecular mass of the compound is 137.32 g/mol.

An empirical formula can be described as a formula that tells about the relative ratios of different atoms in a compound.

The empirical formula for this compound containing phosphorus and chlorine can be calculated as follows;

As the compound is composed of 22.5% phosphorous and 77.5% chlorine, therefore;

Phosphorus = (22.5/100) × 137.32 = 0.225 × 137.32 = 30.897

Chlorine = (77.5/100) × 137.32 = 0.775 × 137.32 = 106.423

Now we can find the moles of each atom by using their molar mass as follows;

Phosphorus = 30.897 ÷ 30.97 = 0.998 moles

Chlorine = 106.423 ÷ 35.453 = 3.002 moles

Now dividing each mole value by the smallest determined number of moles (0.998) as follows;

Phosphorus = 0.998 / 0.998 = 1 mole

Chlorine = 3.002 / 0.998 = 3.008 ≈ 3 moles

Therefore the molecular formula of the compound will be PCl₃.

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Answer:

b

Explanation:

Answer:

D. Catastrophism

Explanation:

Answer:

Catastrophism is the answer :p lol

Explanation:

The pair of cations out of which one will form a precipitate and the other will not be able to the pair that can be distinguished on the addition of sodium chloride :

1) Barium and Lead → Barium will not form a precipitate but Lead will form PbCl₂. Thus this can be distinguished.

2) Barium and Alumunium → Both will not form a precipitate.

3) Lead and Silver → Both will give precipitate so cant is distinguished.

4) Iron and Calcium → Both will not form a precipitate.

Solubility is described because the maximum amount of a substance on the way to dissolve in a given amount of solvent at a targeted temperature.

Solubility can be categorized into 3 classes. Those are soluble, partly soluble, or insoluble. A soluble solute has a solubility of extra than 1g in step with a hundred ml of solvent.

Solubility is described as the most quantity of a substance that can be absolutely dissolved in a given quantity of solvent and represents an essential idea in fields of research which include chemistry, physics, meals technological know-how, pharmaceutical, and organic sciences.

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The oxidation of the iron ions in the hemoglobin molecule to the ferric state (Fe³⁺) results in the loss of the molecule's ability to bind and transport oxygen.

This oxidation process alters the structure of hemoglobin, rendering it less effective in its primary function of carrying oxygen to body tissues.

Hemoglobin is a protein found in red blood cells that is responsible for transporting oxygen from the lungs to tissues throughout the body. It contains iron ions (Fe²⁺) that bind to oxygen molecules, forming a reversible complex known as oxyhemoglobin. This complex is crucial for oxygen transport.

However, when the iron ions in hemoglobin undergo oxidation to the ferric state (Fe³⁺), the binding affinity for oxygen decreases significantly. The oxidation can be caused by factors such as exposure to certain chemicals or reactive oxygen species. As a result, the oxidized hemoglobin is unable to efficiently bind oxygen, impairing its oxygen-carrying capacity and potentially leading to reduced oxygen delivery to tissues.

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The determined percent error is 2.67%, the uncertainty of the metric graduation is 0.025 cm, and the length of the line is 3.75 cm.

a) The uncertainty of the metric graduation can be calculated as the half of the smallest division on the ruler, which is 0.05 cm in this case. Therefore, the uncertainty would be 0.05 cm / 2 = 0.025 cm.

b) To determine the length of the line shown below the metric scale, we need to make an estimate of the position of the line relative to the scale. Based on the image, it appears that the line is approximately between 3.7 cm and 3.8 cm. Therefore, we can estimate the length of the line to be around 3.75 cm.

3. The percent error, it is calculated as follows:

(True Value - Measured Value) / True Value * 100% is the formula for percent error.

For the student's measurement of 3.65 cm, the percent error would be:

Percent error = (3.65 - 3.75) / 3.75 * 100% = -2.67%

This implies that the student's measurement was 2.67% lower than the true value reported by the instructor.

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The complete question is:

The formulae of the metal according to the law of multiple proportions are XCl₂ and XCl₃, and X is Fe so FeCl₂ and FeCl₃

We have the two chlorides that are XyClw and XyClz. We have to show that the ratios w to z are in small whole numbers.

Compound A = 12.7 g X and 7.1 g Cl, then X must be 5.56 g

Compound B = 16.3 g X and 10.7 g Cl, then X must be 5.56 g.

7.1 x (12.7/16.3) = 5.53 g Cl for each gram of X

10.7 x (12/7/16.3) = 8.34 g Cl for each gram of X. Then what is the ratio of the two Cl numbers: Now, divide both numbers by the smaller one. That is

5.53/5.53 = 1.00

8.34/5.53 = 1.508.

Rounding off 1.508 to 1.50, then you can see that 1.0 to 1.5 is actually 2 to 3 and those are small whole numbers. Within experimental error, the law of multiple proportions is proved to be true.

The compounds must be XCl₂ and XCl₃, and X is Fe so FeCl₂ and FeCl₃ are the compounds.

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According to the graph presented, we can see that NaNO3 has a higher solubility at 30°C, as we can see more than 100 grams of NaNO3 can be dissolved in 100 grams of water, whereas all other solutes will have a way lower value. Letter D

(a) qsys: impossible to determine

(b) ΔEsys: 0

(c) ΔEuniv: inconclusive

What is the determination of the changes in qsys, ΔEsys, and ΔEuniv during the phase change?

In the given information, the circles represent a phase change occurring at constant temperature. However, the information provided does not allow us to determine the value of qsys, which represents the heat transfer to or from the system. Without additional data, we cannot ascertain whether heat is being added or removed from the system.

Regarding ΔEsys, which represents the change in internal energy of the system, it is determined to be zero. This indicates that there is no change in the system's internal energy during the phase change occurring at constant temperature.

Lastly, the value of ΔEuniv, which represents the change in the total energy of the system and its surroundings, is inconclusive based on the given information. Without further details, it is not possible to determine whether the phase change results in a change in the total energy of the system and its surroundings.

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Answer:

false

Explanation:

there are 3 oxygen atoms on the right and 2 on the left

Answer:

No

Explanation:

Right:

H = 2 atoms

O = 2 atoms

Left:

H = 2 atoms

O = 1 atom

+

O = 2 atoms

So the Right side has 4 atoms and the Lefts side has 5 atoms. Therefore, not balanced.

The type of bond present in the picture below for both A and B are “polar covalent bond and "dipole-dipole attraction” respectively.

The ability to form molecules and crystals is made possible by a chemical bond, which is a strong attraction between atoms or ions. The bond may be created by the sharing of electrons in covalent bonds or by the electrostatic interaction between ions that have opposing charges.

Other forms of forces present in molecules of compounds are intermolecular forces such as dipole-dipole attraction" and hydrogen bonds.

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The difference between the two half-reactions' standard reduction potentials is what determines the cell potential of an electrochemical cell. The first half-reaction's standard reduction potential is 0.799V, and the second half-reaction's standard reduction potential is -0.771V.

The electrochemical cell's cell potential is therefore equal to the difference between these two readings, which is equal to 0.799V + (-0.771V) = 0.028V. The cell potential, which indicates the greatest amount of energy the cell is capable of producing, is a crucial electrochemical metric.

It is a gauge of the cell's potential energy and is determined by the difference between the standard reduction potentials of the two half-reactions. The more energy that can be created by cells depends on their cell potential.

The capacity of the cell to create energy increases with its potential. The electrochemical cell in the example can only generate a negligibly small quantity of energy, as indicated by its cell potential of 0.028V.

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Answer:

what is the question?

Explanation:

if you tell me ill update it if i got the info

Based on your understanding of the process of photosynthesis, predict what will happen to a plant leaf that loses CO2 too quickly. This event will have no effect on the rate of photosynthesis in the leaf. Photosynthesis in the leaf will slow down or possibly stop.

Future carbon dioxide concentrations ([CO2]) predictions indicate that plant reactions to atmospheric carbon dioxide will be a major concern. Increased photosynthesis results in higher levels of biomass and carbohydrates produced by plants when [CO2] levels are elevated. Between species as well as within species, different organs receive the extra carbs. These carbohydrates serve as an important source of energy for plant growth, but they also function as signaling molecules and have a variety of other functions besides providing carbon and energy. The greater concentration of carbohydrates generated under increasing [CO2] is currently unknown to have any impact on the sugar sensing and signaling pathways of plants.

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Answer:

nonpolar

Explanation:

A nonpolar solvent has the highest solubility with a nonpolar solute.

The statement “The products obtained by the acid-catalyzed hydration of 1-methylcyclohexene and methylenecyclohexene are identical” is not true.

Acid-catalyzed hydration is a chemical reaction that transforms an alkene to an alcohol by adding water.

For instance, in the following reaction, 2-methylpropene reacts with water, with the aid of sulfuric acid, to give the alcohol tert-butyl alcohol.

In general, acid-catalyzed hydration of an alkene takes place via a mechanism known as a Markovnikov addition. When an unsymmetrical alkene is hydrated using H2SO4 and H2O, a mixture of products is usually produced. This is because of the differing stabilities of the carbocation intermediates formed during the reaction. This is referred to as carbocation rearrangement.

A simple example of carbocation rearrangement can be seen in the hydration of 1-methylcyclohexene. It produces two isomeric products: 1-methylcyclohexanol and 3-methylcyclohexanol.

Methylcyclohexene undergoes acid-catalyzed hydration to form a mixture of 1-methylcyclohexanol and 3-methylcyclohexanol. Methylenecyclohexene, on the other hand, yields only cyclohexanol during hydration.

Thus, the given statement is false.

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Answer:

answer is b

Explanation:

please follow me

Answer:

Coppell zinc,ironic bond

Explanation:

lt will give away two zinc atoms

Answer:

I will go with Sodium chlorine NaCl

The molar concentration of nitrate ions in the resulting solution is 0.20M.

Molar concentration, also known as molarity, quantity concentration, or substance concentration, is a unit used to describe the amount of a substance in a solution expressed as a percentage of its volume. The number of moles per liter, denoted by the unit symbol mol/L or mol/dm3 in SI units, is the most often used unit denoting molarity in chemistry. One mol/L of a solution's concentration is referred to as one molar, or 1 M.

Now let us come to our problem statement;

Nitrate from NaNO₃:

75.0 mL × 0.20 M = 15 mmol NaNO₃ = 15 mmol NO₃⁻

Nitrate from Ba(NO₃)₂:

25.0 mL × 0.10 M = 2.5 mmol Ba(NO₃)₂

2.5 mmol Ba(NO₃)₂ × \(\frac{2mmol NO3}{1mmol Ba(NO3)2}\)  = 5.0 mmol NO₃⁻

So the final number of NO₃⁻ moles is (15 + 5) 20 mmol.

The final volume is (75 + 25) 100 mL.

So the molar concentration is:

20 mmol / 100 mL = 0.20 M

The molar concentration of nitrate ions in the resulting solution is 0.20M.

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The unknown substance that is most likely carbon, given the various data from the question is substance 2 (option B)

To know which substance is carbon, we shall determine the density of each substance. Details below:

For substance 1:

Density = mass / volume

Density = 6.95 / 4

Density of substance 1 = 1.74 g/cm³

For substance 2:

Density = mass / volume

Density = 4.54 / 2

Density of substance 2 = 2.27 g/cm³

For substance 3:

Density = mass / volume

Density = 5.4 / 3

Density of substance 3 = 1.8 g/cm³

For substance 4:

Density = mass / volume

Density = 10.35 / 5

Density of substance 4 = 2.07 g/cm³

Thus, from the above calculation, the substance that is carbon is substance 2 (option B)

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The variation in the density values obtained by two different students could be due to experimental error, inherent measurement uncertainties, or differences in technique or procedure.

When measuring the density of a substance, there are various factors that can introduce variability in the results. The density is typically determined by dividing the mass of the substance by its volume. In this case, both students used the same urine sample and lab equipment, which eliminates any differences related to the sample or the instruments used.

However, there are still several sources of potential error. First, there may be slight differences in the handling and preparation of the urine sample between the two students. Small variations in temperature, contamination, or evaporation can affect the density measurement.

Secondly, the measurement process itself involves inherent uncertainties. The precision of the measuring instruments, such as the balance and the volumetric apparatus, can introduce slight variations in the obtained values. Additionally, reading errors or parallax when reading the instruments can also contribute to differences in the results.

Lastly, the students' individual techniques and approaches to measuring the density may differ slightly. Factors such as how they handle the equipment, how they record measurements, or how they account for experimental conditions can all influence the final density value.

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Answer:

The amount of isopropyl alcohol contained in 150 ml of the solution is 117.15 grams

Explanation:

The density of a substance is the mass per unit volume, therefore, we have;

The density of the isopropyl alcohol = 0.785 g/ml at 25°C

The  density = mass/volume

Mass = Density × Volume

The mass of the 150 ml of isopropyl alcohol is therefore;

Mass = 0.785 g/ml × 150 ml = 117.15 g

The amount in grams contained in 150 ml of sample = 117.15 g.

The order of strength of hydrogen bonds, dispersion forces, and dipole-dipole forces is as follows: Hydrogen bonding , Dipole-dipole interactions ,London dispersion forces.

Hydrogen bonding: Hydrogen bonding is the strongest type of intermolecular force. It occurs when a hydrogen atom is covalently bonded to a highly electronegative atom (such as nitrogen, oxygen, or fluorine) and is attracted to another highly electronegative atom in a nearby molecule. An example of a molecule that exhibits hydrogen bonding is water (H2O). Dipole-dipole interactions: Dipole-dipole interactions are slightly weaker than hydrogen bonding, but still stronger than London dispersion forces. They occur between molecules that have permanent dipoles, or regions of partial positive and negative charge. An example of a molecule that exhibits dipole-dipole interactions is acetone (CH3COCH3). London dispersion forces: London dispersion forces are the weakest type of intermolecular force. They are attractive forces that occur between all types of molecules and result from the temporary separation of charge that occurs as a result of the movement of electrons within a molecule. An example of a molecule that exhibits London dispersion forces is hexane (C6H14).

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Answer:

model of water

Explanation:

Answer:

Modern periodic table has eighteen (18) vertical columns. These are called groups

Due of their propensity to create ionic connections by giving up electrons, group 2 elements all share this trait. option (d) is correct.

The negatively charged particles known as electrons revolve around the outer edges of the nucleus. For scientists, it can be challenging to monitor them because of how quickly they spin. The tiniest particles in an atom, you can put 20,000 of them inside a proton, they are drawn to the positive ion of the protons.

Same-group electrons have similar chemcial and physical characteristics. Group-2 is the alkaline earth metals which have tendency to lose two electrons to form the M+2 types of metal ions as after losing two electrons they get the Noble gas configuration.

Since they tend to lose electrons therefore they will form ionic bond with non-metals and results to form the ionic compounds.

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The Complete Question :

what do all group 2 elements have in common? (2 points) group of answer choices

(a) they all gain two electrons to form a stable outer energy level.

(b) they form covalent bonds with halogens.

(c) they all react easily with the noble gases

(d) they tend to form ionic bonds by losing electrons.

Due of their propensity to create ionic connections by giving up electrons, group 2 elements all share this trait.

Thus, they tend to form ionic bonds by losing electrons, this is the correct option.

The negatively charged particles known as electrons revolve around the outer edges of the nucleus. For scientists, it can be challenging to monitor them because of how quickly they spin. The tiniest particles in an atom, you can put 20,000 of them inside a proton, they are drawn to the positive ion of the protons.

Same-group electrons have similar chemical and physical characteristics. Group-2 is the alkaline earth metals which have tendency to lose two electrons to form the M+2 types of metal ions as after losing two electrons they get the Noble gas configuration.

Since they tend to lose electrons therefore they will form ionic bond with non-metals and results to form the ionic compounds.

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If the lungs do not function to eliminate sufficient CO2, you might expect Serum bicarbonate levels to increase.

When the lungs do not eliminate enough CO2 from the body, the concentration of CO2 in the blood increases. An increase in CO2 in the blood results in a decrease in blood pH. To compensate for the decreased pH, the kidneys produce and retain more bicarbonate ions in the blood.

Bicarbonate acts as a base and can help to neutralize the excess H+ ions in the blood.The amount of bicarbonate in the blood is regulated by the kidneys. When the kidneys detect an increase in H+ ions in the blood, they produce and retain more bicarbonate ions.

Similarly, when the kidneys detect a decrease in H+ ions in the blood, they excrete more bicarbonate ions. This helps to maintain the pH of the blood within a narrow range, which is necessary for the proper functioning of the body.

Hence, if the lungs do not function to eliminate sufficient CO2, Serum bicarbonate levels will increase.

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