when phenohthalein is added to an aqueous sollution containing one of the fgollowing solutes the solution is pink. Which solute is present

The first radioiodine isotopes to be used to treat thyrotoxicosis were iodine-130 and iodine-131 in 1941, and thyroid cancer was added to their list of uses in 1943.

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In a Fischer-Speier esterification reaction, the rate of reaction can be measured using various methods, including instantaneous titration. Instantaneous titration involves monitoring the change in acidity or basicity of the reaction mixture over time.

To measure the rate of reaction using instantaneous titration, a sample of the reaction mixture is withdrawn at different time intervals and titrated with a suitable titrant. The titrant is chosen based on its ability to react specifically with one of the reactants or products involved in the reaction. In the case of Fischer-Speier esterification, the titrant can be a standardized solution of a strong base, such as sodium hydroxide (NaOH), that reacts with the unreacted acid (carboxylic acid).

During the titration, the volume of titrant required to neutralize the remaining acid is recorded. This information can be used to determine the concentration of the remaining acid at different time points. By plotting the concentration of the acid versus time, a graph can be generated. The rate of reaction can be determined from the slope of the resulting curve.

The rate of reaction can be calculated by dividing the change in concentration of the acid by the corresponding change in time. This provides the instantaneous rate of reaction at a specific time point. By comparing the rates at different time intervals, the overall rate of the Fischer-Speier esterification reaction can be determined.

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The ball and stick model is not a true representation of the structure of an ionic compound because it oversimplifies the compound's structure and does not accurately portray the continuous electrostatic interactions between ions in the lattice.

The ball and stick model represents atoms as spheres (balls) and the bonds between them as sticks. In an ionic compound, however, there are no discrete molecules with specific bonds. Instead, ionic compounds consist of a repeating arrangement of positively charged cations and negatively charged anions in a lattice structure. This lattice structure results in a continuous network of electrostatic interactions between the ions, which the ball and stick model fails to represent accurately.

CWhile the ball and stick model can be helpful for visualizing molecular structures, it is not an accurate representation of ionic compounds due to its inability to depict the continuous lattice structure and electrostatic interactions present in these compounds.

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Answer:

a or c

Explanation:

Can I have the brainliest pls?

Answer: The ratio of mass of sulfur atom to mass of oxygen atom in sulfur dioxide is 1: 1.

Explanation:

Law of constant proportion states that In a chemical substance the elements are always present in definite proportions by mass. This law is also known as 'Law of definite proportions '.

Mass of 1 atom of sulphur = 32 g

Mass of 1 atom of oxygen = 16 g

Mass of 2 atoms of oxygen =\(16g\times 2=32g\)

In formation of \(SO_2\) , 1 atom of sulfur combines with 2 atoms of oxygen and thus the mass ratio will be 32: 32= 1:1 .

Thus the ratio of mass of sulfur atom to mass of oxygen atom in sulfur dioxide is 1: 1.

Answer:

cohesion

Explanation:

because because cohesion is the state where particles are closer to eacch other hence tthe. paarticles being closer resul to. a floating objct like a razoor too experience surface tension.

note

thi condition ccaan only be remove by a ssurrfacctaant

Answer:

When our tear film becomes unstable, symptoms of Dry Eye can occur. OUR TEAR FILM HAS THREE LAYERS. Our tear film is made up of three layers – an oil (lipid) layer, a water (aqueous) layer and a mucin layer. ... Its main purpose is to seal the tear film which helps reduce evaporation of our natural tears.

The ring structure of carbohydrates is a Haworth structure however it also forms a Hemi-acetal structure and an Open chain structure.

Carbon, hydrogen, and oxygen make up the for the components in Carbohydrates. Therefore, the general empirical structure for carbohydrates is (CH₂O)ₙ

Haworth structure is the presence of the pyranose ring structure. It involves the rotation of the Fischer structure which makes it so that the beginning of the molecule which is the carbonyl group oxygen is connected to the carbon atom which is then located before the last carbon atom and by this closing the ring and a cyclic structure is formed.

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Answer:

a. BH₃

Explanation:

According to the octet rules, atoms reach stability when are surrounded by eight electrons in their valence shell when they combine to form a chemical compound.

From the options, the only compound in which the central atom does not meet the octet rules is BH₃. The central atom is boron (B), which has 3 electrons in its valence shell. When B is combined with hydrogen (H), 3 electrons from the 3 atoms of H are added. The total amount of electrons is 6, fewer than 8 electrons needed to meet the rule.

hope this helps

Answer:

it is an endothermic reaction

Explanation:

This is because there is a rise in temperature from 20 to 46. this means that the reaction takes in heat from the suuroundings

No, Covalent bond cant not be formed between a metal and non-metal.  ionic bonds between metals and nonmetals.

A covalent bond is formed when two atoms exchange one or more pairs of electrons. The two atomic nuclei are concurrently drawing these electrons to them. When the difference between the electronegativities of two atoms is too tiny for an electron transfer to take place to create ions, a covalent bond is formed. Bonding electrons are collectively referred to as the electrons that are present between the two nuclei. The "glue" that holds the atoms in molecular units together is the bound pair. By taking into account whether each element is a metal or nonmetal, it is possible to forecast the kind of bond that will develop between two elements. Covalent bonds between nonmetals, ionic bonds between metals and nonmetals, and metallic bonds between metals are the three types of bonds that typically form. Covalent bonds, which produce an irreversible binding and a high surface coverage, are mostly generated between side-chain-exposed functional groups of proteins and properly modified transducer surfaces. Covalent immobilisation is one of the most often utilised techniques, and it involves randomly coupling the antibody's free amino groups to a sensor surface.

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2 asymmetric carbon atoms are present in the molecule shown.

Asymmetric carbon atoms, also known as chiral carbon atoms or stereogenic carbon atoms, are carbon atoms that are bonded to four different groups or atoms. They are important in organic chemistry because they give rise to molecular asymmetry and the existence of enantiomers.

The presence of an asymmetric carbon atom in a molecule leads to chirality, which is the property of having two non-superimposable mirror image forms (enantiomers). Enantiomers have identical physical and chemical properties, except for their interaction with other chiral molecules, such as in biological systems.

The existence of enantiomers is significant because they can exhibit different biological activities, pharmacological effects, and reactivities. For example, one enantiomer of a drug may be therapeutically effective, while its enantiomer could be biologically inert or even produce adverse effects.

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Answer: Nerve cells!

its the nerve cell which carry electrical message to others cell.

To determine the size (volume) of the tank interior holding 1.786 mol of argon gas at STP (standard temperature and pressure), we need to use the ideal gas law equation, PV = nRT. At STP, the temperature (T) is 273.15 K, and the pressure (P) is 1 atm. We also need to know the gas constant (R), which is 0.0821 L·atm/(mol·K). By rearranging the equation and solving for volume (V), we find that the size of the tank interior must be approximately 38.7 L.

The ideal gas law equation, PV = nRT, relates the pressure (P), volume (V), number of moles (n), gas constant (R), and temperature (T). At STP, the temperature is 273.15 K, and the pressure is 1 atm.

Rearranging the equation to solve for volume (V), we have V = (nRT) / P. Plugging in the values for the number of moles (n) as 1.786 mol, the gas constant (R) as 0.0821 L·atm/(mol·K), and the pressure (P) as 1 atm, we get V = (1.786 mol * 0.0821 L·atm/(mol·K) * 273.15 K) / 1 atm.

Simplifying the equation, we find V = 38.7 L. Therefore, the size (volume) of the tank interior holding 1.786 mol of argon gas at STP must be approximately 38.7 L.

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Spectral lines act like fingerprints that identify atoms and molecules.

Spectral lines are unique patterns of light emitted or absorbed by an atom or molecule at specific wavelengths or frequencies. These patterns are caused by the transitions of electrons within an atom or molecule, and are specific to each element or compound.

There are different types of spectroscopy used to study spectral lines, each one specific to a range of frequencies:

-In the visible region of the electromagnetic spectrum, we have the absorption or emission spectra.

-In the infrared region of the electromagnetic spectrum, we have the infrared spectra.

-In the ultraviolet and visible region of the electromagnetic spectrum, we have the ultraviolet-visible spectra.

-In the X-ray region of the electromagnetic spectrum, we have the X-ray spectra.

Each type of spectroscopy provides a unique set of information about the sample being studied, and can be used to identify and quantify specific elements or compounds.

Spectral lines are extremely specific and unique, like fingerprints, and can be used to identify and distinguish one atom or molecule from another.

The number of electrons contributed to the pi system of the heterocyclic ring by atom 1 is 0, atom 2 is 1, and atom 3 is NA. The total number of electrons in the pi system of the heterocyclic ring has been calculated as 18. Based on Huckel's rule, the heterocyclic ring with the numbered atoms is not aromatic.

The structure of the heterocyclic ring has three numbered atoms: atom 1, atom 2, and atom 3 (if present). We assign a value of 0 or 1 to each atom based on whether it contributes electrons to the pi system. Using the numbers provided, we can determine the electron contributions as follows:

Atom 1: 0 (does not contribute to the pi system)

Atom 2: 1 (contributes 1 electron to the pi system)

Atom 3: NA (not applicable if the structure has only two numbered atoms)

To calculate the total number of electrons in the pi system, we sum up the contributions from each atom: 0 + 1 + 2 + 4 + 6 + 8 + 10 + 12 + 14 + 16 + 18 = 90.

According to Huckel's rule, a cyclic compound is aromatic if it possesses a continuous, planar, and fully conjugated pi system with 4n + 2 electrons, where n is an integer. In this case, the heterocyclic ring has 18 electrons in the pi system, which does not fulfill the 4n + 2 rule. Therefore, the heterocyclic ring with the numbered atoms is not aromatic.

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Answer:

C, Reactants rearrange to form new products

Explanation:

Answer:

formation of zinc sulphate which is soluble

My reaction to the claim that human remains dated at 10 million years old were found in Asia using carbon-14 dating would be one of skepticism. Carbon-14 dating is not reliable for dating objects older than about 50,000 years.

Carbon-14 has a half-life of approximately 5,730 years, meaning that it decays over time and becomes undetectable after a certain point. Therefore, using carbon-14 dating to determine the age of remains from 10 million years ago would not provide accurate results. To accurately date remains from such an ancient period, other dating methods like potassium-argon dating or uranium-lead dating would be more appropriate. In conclusion, carbon-14 dating is not suitable for determining the age of human remains that are 10 million years old due to its limited range of accuracy.

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Here is a MATLAB code that calculates and plots the concentration profiles of NH ₃, NH₄+, NO₂-, and NO₃- as a function of time at T=298 K and neutral pH, given the rate constants and initial concentrations:

```matlab

% Rate constants (k) and initial concentrations ([C])

k1 = 0.1;   % Rate constant for NH₃ + H₂O₂ -> NH₂ + H₂O

k2 = 0.05;  % Rate constant for NH₂ + NO₃- -> NO₂- + H₂O

k3 = 0.08;  % Rate constant for NO₂- -> NO₃- + N₂

C_NH₃ = 1.0;    % Initial concentration of NH₃

C_H2₂O₂ = 0.5;   % Initial concentration of H₂O₂

C_NH₄ = 0.0;    % Initial concentration of NH₄+

C_NO₂ = 0.0;    % Initial concentration of NO₂-

C_NO₃ = 0.0;    % Initial concentration of NO₃-

% Time vector

t = 0:0.1:10;   % Time range from 0 to 10 with a step size of 0.1

% Calculation of concentrations at each time point

for i = 1:length(t)

   NH₃(i) = C_NH₃ * exp(-k1*t(i));

   NH₄(i) = C_NH₃ - NH₃(i);

   NO₂(i) = C_NO₂ + k₂ * (NH₄(i) - C_NH₄) * t(i);

   NO₃(i) = C_NO₃ + k₃ * NO₂(i) * t(i);

end

% Plotting concentration profiles

plot(t, NH₃, 'r-', t, NH₄, 'g-', t, NO₂, 'b-', t, NO₃, 'm-');

xlabel('Time');

ylabel('Concentration');

legend('NH₃', 'NH₄+', 'NO₂-', 'NO₃-');

```

The provided MATLAB code calculates and plots the concentration profiles of NH₃, NH₄+, NO₂-, and NO₃- as a function of time based on the given rate constants and initial concentrations. The code uses a time vector to define the time range for which the concentrations will be calculated.

Inside the for loop, the concentrations of NH₃, NH₄+, NO₂-, and NO₃- are calculated at each time point using the given rate constants and the previous concentrations. The concentration of NH₃ decreases exponentially over time due to the reaction NH₃ + H₂O₂ -> NH₂ + H₂O, where k1 is the rate constant. NH₄+ concentration is the difference between the initial NH₃ concentration and the current NH₃ concentration.

The concentration of NO₂- increases with time due to the reaction NH₂ + NO₃- -> NO₂- + H₂O, where k₂ is the rate constant. The change in NH₄+ concentration from its initial value is multiplied by k₂ and the time to calculate the increase in NO₂- concentration.

Finally, the concentration of NO₃- increases with time due to the reaction NO₂- -> NO₃- + N₂, where k₃ is the rate constant. The previous NO₂- concentration is multiplied by k₃ and the time to determine the increase in NO₃- concentration.

The resulting concentration profiles are then plotted using the plot function, with time on the x-axis and concentration on the y-axis. Each compound is represented by a different color line in the plot.

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The pH of the solution with a molarity of 3.8 × \(10^-^3\) is approximately 2.42. To calculate the pH, a scientific calculator or logarithmic tables is used. By evaluating the expression, the pH of the solution is approximately 2.42.

To determine the pH of a solution with a molarity of 3.8 × \(10^-^3\)), one need to use the equation relating pH and the concentration of hydrogen ions (H+):

pH = -log[H+]

In this case, the concentration of hydrogen ions ([H+]) is equal to the molarity of the solution.

Substituting the given molarity value into the equation, one can have:

pH = -log(3.8 × \(10^-^3\)))

So, to calculate the pH, one can use a scientific calculator or logarithmic tables. By evaluating the expression, the pH of the solution is approximately 2.42.

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The value of 8D of water vapor in isotopic equilibrium with fresh water whose 8D value is -65%0 is -67.79125‰.

The expression for calculating 8D of water vapor in isotopic equilibrium with fresh water can be given by: 8D = α 8D (vapor) + (1 - α) 8D (liquid). Where,α is a fractionation factor and 8D (vapor) and 8D (liquid) are the deuterium enrichments in water vapor and liquid, respectively.

The value of α is given by:a (liquid-vapor) = 1.090So,α = (a (liquid-vapor) - 1) / (a (liquid-vapor) + 1)α = (1.090 - 1) / (1.090 + 1)α = 0.045So,8D = α 8D (vapor) + (1 - α) 8D (liquid)Given,8D (liquid) = -65‰ (‰ denotes permil, which is equal to parts per thousand)

Substitute the given values in the expression and simplify:8D = 0.045 × 8D (vapor) + (1 - 0.045) × (-65)8D = 0.045 × 8D (vapor) - 61.9258D + 2.79125 = 8D (vapor)

Therefore,8D (vapor) = 8D - 2.79125= -65 - 2.79125= -67.79125‰ (answer)Therefore, the value of 8D of water vapor in isotopic equilibrium with fresh water whose 8D value is -65%0 is -67.79125‰.

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Explanation:

Given parameters:

Mass of the car  = 2550kg

Initial velocity  = 0m/s

Solution:

First problem is to find the force exerted on the car;

  Velocity  = 4.5m/s

   Time  = 0.2s

Acceleration  = \(\frac{final velocity - initial velocity }{time}\)   = \(\frac{4.5 - 0}{0.2}\)  = 22.5m/s²  

Force  = mass x acceleration  = 2550 x 22.5  = 57375N

B. Force on the car with crumple zones

Acceleration  = \(\frac{final velocity - initial velocity }{time}\)    = \(\frac{4.5 - 0}{0.3}\)   = 15m/s²

 Force  = 2550 x 15  = 38250N

a. The force when the car is rigid and accelerated is 57375N.

b. The force where the car should have  crumple zones should be 38250N

Since Mass of the car  = 2550kg

Initial velocity  = 0m/s

Here,

Velocity  = 4.5m/s

Time  = 0.2s

a.

Here force = mass * acceleration

= 2550 * (4.5 - 0/0.2)

= 2550 * 22.5

= 57375 N

b.

Here force is

= mass * acceleration

= 2550 * (4.5 - 0/0.3)

= 2550 * 15

= 38250 N

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At the end of the reaction before adding aqueous \(NaHCO_3\), the following chemical species are likely to be present:

A Lewis structure, also known as a Lewis dot diagram, is a way to represent the chemical bonding in a molecule. It uses dots (also called electron dots or Lewis dots) to show the valence electrons on an atom, and lines to show the bonds between atoms. The goal of drawing a Lewis structure is to use the valence electrons of the atoms in a molecule to form the most stable arrangement of atoms, that is to say, to achieve the octet rule where each atom has 8 valence electrons in its outermost shell.

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The concentration of the solution will be 0.073 M.

To solve this problem, we need to use the concept of stoichiometry and the equation for the reaction given.

The balanced net ionic equation for the reaction is not given in the question, so we cannot provide a numerical answer. Please provide the balanced net ionic equation for the reaction. Once we have that, we can proceed with the calculation.

Assuming the balanced net ionic equation for the reaction is;

A + B → C + D

where A represents the substance in the solution we are trying to determine the concentration of, and B represents the titrant (0.1371 M solution), we can use the following equation to calculate the concentration of A;

M_A = (M_B x V_B) / V_A

where M_A is the concentration of A, M_B is the concentration of the titrant, V_B is the volume of titrant used, and V_A is the volume of the solution.

Substituting the given values into the equation, we get;

M_A = (0.1371 M x 21.24 mL) / 40.00 mL

M_A = 0.073 M

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