A solution is prepared by dissolving 23. 7 g of cacl2 in 375 g of water. The density of the resulting solution is 1. 05 g/ml. The concentration of cacl2 is __________% by mass.

The atomic number will be 12 and the element is magnesium.

What is electronic configuration?

Also called electronic structure ,it is the arrangement of electrons in orbits around the nucleus. The electron configuration of atoms in quantum mechanical models is given by ordering the occupied orbitals in order of packing, with the number of electrons in each orbital indicated as a superscript.

What is atomic number?

The atomic number, or atomic number of a chemical element, is the number of electric charges in the nucleus. For normal atomic nuclei, this equals the number of protons, or the number of protons found in the nucleus of each atom of that element.

Therefore, the atomic number will be 12 and the element is magnesium.

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Along with the Aufbau principle and Hund's rule, the Pauli Exclusion principle is one of the key concepts governing the arrangement of electrons in an atom.

According to the Pauli exclusion principle, no two electrons may simultaneously hold the same set of quantum numbers or quantum states. A distinct quantum number and set of quantum states should exist for every electron.We learned from the definition of the Pauli exclusion principle that no two electrons with the same spin can be placed together at once, and no two electrons with the opposite spin can be ordered in a single quantum state. The Pauli exclusion principle is just as significant in chemistry as it is in physics.

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4.1g of sodium phosphate is required to prepare 250.0 ml of a solution that is 0.30 m in sodium ion.

The important thing to note here is that each mole of trisodium phosphate ([tex]Na_{3}PO_{4}[/tex]) gives us 3 moles of Na ions. So a solution that is 0.30 M in sodium ion is only 0.10 M in [tex]Na_{3}PO_{4}[/tex].

Now, molarity is moles/L, so we can figure out the total number of moles we need:

0.10 mol/L × 0.250 L = 0.025 moles [tex]Na_{3}PO_{4}[/tex].

Finally, the MW of [tex]Na_{3}PO_{4}[/tex] = 164 g/mol.

So: 0.025 moles × 164 g/mol = 4.1 g

So you would need 4.1 g of trisodium phosphate to make 250 mL of this solution.

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The statement that describes a way in which humans could increase biodiversity in a marine ecosystem is as follows: Fish populations increase as dissolved oxygen decreases (option A).

Biodiversity is the diversity (number and variety of species) of plant and animal life within a region.

It can be used more specifically to refer to all of the species in one region or ecosystem. Biodiversity refers to every living thing, including plants, bacteria, animals, and humans.

Marine ecosystem are aquatic environments with high levels of dissolved salt. These include the open ocean, the deep-sea ocean, and coastal marine ecosystems, each of which has different physical and biological characteristics.

The biodiversity of a marine ecosystem can be illustrated by the increase in fish populations in the marine environment, hence, option A is correct.

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The sample of water containing 0.004 ml of oxygen in 2000 ml of water is equivalent to 2× 10⁻⁴ volume percentage of the solution.

Volume percentage of an aqueous solution is the ratio of the  volume of the dissolved substance to the total volume of the solution. Volume percentage is thus, used to express the concentration of the solution in terms of its volume.

The other terms used to express the concentration of a solution are molarity, normality, mass percentage, ppm etc.

Given the total  volume of the water sample = 2000 ml

volume of oxygen dissolved in water = 0.004 ml

volume percentage = volume of oxygen / total volume ×100

                                 = 0.004 /2000 ×100 = 2× 10⁻⁴

Therefore, 2000 ml water sample containing 0.004 ml of sample is equivalent to 2× 10⁻⁴ volume percentage.

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The partial pressure of He in the tank when total pressure is given is calculated as : 3.649 atm.

When a container is filled with more than one gas, then each gas exerts pressure. So , the pressure of any one gas within the container is called its partial pressure.

Given 40 g of N2 ; 50 gm of O2 and 10 g of He

Total pressure given 8 atm

Moles of O2 = 50/32

=1.56 moles

Moles of N2 = 40/28

= 1.42 moles

Moles of He = 10/4

= 2.5 moles

Total number of moles= 1.56 + 1.42 + 2.5

= 5.48 moles

= (2.5/5.48) * 8

Partial pressure of He =3.649 atm.

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Number of moles of carbon monoxide gas that were collected is 0.585 mol and the mass of carbon monoxide gas is 25.7 g

In an evacuated flask with a measured volume of 30.0L, carbon dioxide gas is collected at a temperature of 27.0 °C. The pressure within the flask is 0.480atm once all the gas has been collected.

Determine the volume and moles of the carbon dioxide gas that was gathered. Make sure you have the right number of significant digits in your response.

T = 27.0°C ˖ 273.15 = 300.2 K

V = 30.0 L

P = 0.480 atm

n = ?

m = ?

Determine the number of moles of CO₂

The ideal gas equation can be used to determine the moles of CO₂.

P×V = n×R×T

n= (P×V)/(R×T) = (0.480×30.0)/(0.08206×300.2) = 0.585 mol

Calculate the CO₂ mass.

The molar mass is calculated to be 44.01 g/mol.

0.585 × 44.01 = 25.7 g

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SrCl₂ is soluble salt  to precipitate one cation while keeping the other cation in solution.

Cations are ions that are polarized. Anions are the name for negatively charged ions. Ions are charged atoms or molecules. If one or more of an atom's electrons are removed, it will transform from a balanced atom together into positive charges cation. If an unbalanced atom gains one or more electrons, it will transform into a negatively charged anion.

Due to mercurous, we can dilute any solution containing chloride ions to use as a NaCl solution.

Hg₂²⁺ is made up of group I cations that precipitated as chloride Sr²⁺ is from group V .

Net ionic equation:

Hg₂²⁺ + 2 Cl⁻  → Hg₂Cl₂

while SrCl₂ is soluble salt.

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A cholesterol test is a blood test that quantifies your blood's levels of cholesterol and certain fats. Every cell in your body, including the ones that make up your blood, contains cholesterol, a waxy, fatty-like substance.

Elevated blood ammonia (BUN) and creatinine are measured during kidney function testing, often known as renal panels. Aspartate analyzer (ALT), alkaline phosphatase (ALP), transaminase (AST), bilirubin, albumin, and total protein are all measured in liver function tests.

In patients suffering from viral infections or immunological disorders, scientific tests are particularly helpful in establishing a diagnoses, predicting clinical symptoms, and tracking disease progression. In the management of diseases, timely diagnostic evaluation and the use of accurate tests are crucial.

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Total random kinetic energy of all the molecules in one mole of hydrogen at temperature of 300 K is 3741.3 J. Speed with which a mole of hydrogen have to move so that kinetic energy of the mass is equal to the total random kinetic energy of its molecules is 7482.6 m/s

According to kinetic theory, average kinetic energy of gas molecules depends on the absolute temperature. At given temperature, molecules of all the gases have same average kinetic energy".

Kinetic energy = 3/2 * R T

= 3/2 * 8.314 * 300

= 3741.3 J

KE = 1/2 * m v²

v² =  2 KE/m

= 2* 3741.3 /1

Speed =  7482.6 m/s

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Rf will be 0.697

Retention factor can be defined as;

The ratio of  distance travelled by substance to the distance travelled by solvent. Substances start at the origin. The starting point of the compound is called the origin. This is where we measure the distance moved by the substance.

According to the question;

The given data is:

spot distance  =   9.9 cm

solvent distance =  14.2 cm

We will have to find the retention factor value:

Rf = ?

The formula to find Rf is as follows;

Rf = spot distance / solvent distance

Rf = 9.9 cm / 14.2 cm

The answer after the solution is :

Rf = 0.697

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The classifications of the reactions are;

A . Synthesis

B. Decomposition

C. Combustion reaction

D. Single replacement

E. Double replacement

We know that in chemistry, what we call a reaction has to do with the interaction that is taking lace between two or more substances and leads to the production of a new substances. We have to look at the reacts that are here and then know how to classify each one.

In fact the combustion reaction has to do with the burning of a species in air. A single replacement has to do with the substitution of a given specie in a compound with another. A double replacement reaction has to do with a case where the anions interchange cation partners. The synthesis reaction deals with the production of new compounds while the decomposition reaction has to do with the compound into its components.

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Average kinetic energy is the average sum of all kinetic energy of all the molecules of gases. Therefore, the kinetic energy of the cart is 450J. Average kinetic energy is directly proportional to temperature.

It is a energy which is possess  by a moving object. It is very difficult to find the correct value of kinetic energy so we find average kinetic energy. Which is very easy to calculate as compared to calculating kinetic energy.  It is not dependent on the type of gases or mass of gases.

Mathematically,

K.E=1/2mv²

Where,

m= mass of object= 225 kg

v= velocity of object= 2 m/s

substituting all the given values in the above equation, we get

K.E=1/2×225 ×2²

K.E=450J

Therefore, the kinetic energy of the cart is 450J.

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The pH of a buffer in which  the concentration of HOCl is 6.50 x 10⁻⁴ M and that of  NaOClis 7.50 x 10⁻⁴ M( the ka of HOCl is 3.0 x 10⁻⁸) is 7.51.

We can find out the pH of the buffer solution by Henderson-Hasselbalch equation, derived by Lawrence Joseph Henderson and Karl Albert Hasselbalch. It is given as:

pH = pKa + log [A⁻] / [HA]

Here,

pH is the acidity of the solution

pKa is the negative logarithm of Ka (ionization constant of acid)

[A⁻]  is the concentration of salt/ conjugate base

and [HA] is the concentration of acid.

given,

concentration of NaOCl, [A⁻] = 7.50× 10⁻⁴ M

concentration of HOCl [HA] = 6.50 × 10⁻⁴ M

Ka of HOCl = 3.0 × 10⁻⁸

∵ pKa = -log(Ka)

pKa = -log(3.0 × 10⁻⁸)

pKa= 7.45

Putting these values in Henderson-Hasselbalch equation:

pH = 7.45 + log 7.50× 10⁻⁴ M/6.50 × 10⁻⁴ M

pH = 7.45 + log 7.50/6.50

pH = 7.45 + log 1.15

pH = 7.45 + 0.06

pH = 7.51

Thus,  the pH of the buffer is 7.51.

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The balanced chemical equation for the reaction associated with the heat of formation for [tex]AgNO_{3}[/tex]

Decomposition is a type of chemical reaction when a single reactant breaks down into two or more different products. The term "thermal decomposition process" refers to the decomposition method used when heat is present.

The enthalpy change that takes place when 1 mole of a substance is created from its component elements in their standard states is known as the standard enthalpy of formation. A pure element has a standard enthalpy of production of 0 in its normal state.

Enthalpy of formation = Enthalpy change 1 mole of product formed from its original constituents.

[tex]Ag(s) + \frac{1}{2} N_{2}(g) + \frac{3}{2}O_{2} \rightarrow AgNO_{3}[/tex]

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Answer: B3N3H6

Explanation:

I am pretty sure the formula for benzene is B3N3H6. If I am wrong, I am sorry, I learned this a long time ago.

Iron(II) nitrate is an excess reactant left over is equal to 0.1265 mol.

A limiting reagent can be defined as a reactant that is completely finished from the reaction mixture at the completion of a  reaction and is also referred to as a limiting reactant.

Given, a balanced chemical equation of the reaction between iron(II) nitrate and potassium hydroxide is:

[tex]Fe(NO_3)_2 +2KOH\longrightarrow Fe(OH)_2 +2KNO_3[/tex]

Given, the amount of the iron(II) nitrate = 20.0 g

The molecular mass of the iron nitrate = 71.84 g/mol

The number of moles of iron(II) nitrate  = 20.0/71.84 = 0.278 mol

Given the mass of the potassium hydroxide, = 17.0 g

The number of moles of potassium hydroxide = 17/56.11 = 0.303 mol

If 2 mole of KOH react with  iron(II) nitrate = 1

0.303 mol of KOH react with iron(II) nitrate  = 0.303/2 = 0.1515 mol

Therefore,  iron(II) nitrate is an excess reagent.

The iron(II) nitrate is left after reaction = 0.278 - 0.1515 = 0.1265 mol

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Engineered wood products type of building material can be highly combustible and produce toxic gases when exposed to fire.

Its construction materials exhibit a variety of flaws and stone degradation patterns, including color fading, spalling, and flaking.

Materials comprised of wood fibers connected by glue or binders may be extremely flammable, release hazardous fumes, or degrade quickly when exposed to fire. Building firewalls involves using walls.

In North America, wood is the most widely used building material and the foundation of many different structural systems. Wood's response to fire conditions is influenced by its size and moisture content.

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Answer:

c

Explanation:

english please im just guessing

The volume of the mixture is 5 L

The limiting reagent is the one that is completely consumed during a reaction. Reagents that are entirely consumed by a chemical reaction are known as limiting reagents. They are additionally known as limiting reactants or limiting agents.

Reactants in a chemical reaction are referred to as surplus reagents if they are still present at the end of the reaction. Because its quantity restricts the number of products that can be generated, the reagent that is totally consumed or reacted is known as the limiting reagent.

We should first use the mole ratio, and SO 2 as the limiting reagent .

That would yield 5.0 L or 2 moles of SO3, but that is not one of your options. Since the temperature and pressure are both constant, the volume is equal to the number of moles since n/v = p/rt.

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There can be no zero for the main quantum number (n). Therefore, the permitted values for n are 1, 2, 3, 4, and so forth. Any integer between 0 and n – 1 can serve as the angular quantum number (l).

The value of n is between 1 and the outermost electron shell of that atom. Looking at the period (numbered row) of the element on the periodic table will reveal the primary quantum number. The period number and the primary quantum numbers of electrons in the S-block and P-block are identical.

There are three values if n=3 is the primary quantum number. The electron is in a p-orbital state when l=1, and the electron.

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X-rays are a form of indirectly ionizing radiation, and it can be really harmful to the humans health, so limiting the exposure is always a priority. Here, wearing a protective vest is the correct answer.

X-rays are a type of radiation that ionizes indirectly. Remember that ionization is what harms our cells, thus it is best to minimize exposure to these radiation types.

Now when X-rays are strong enough, they can penetrate through many ordinary materials (like wood, plastic, etc.) Also, once it enters in your body, a series of responses begin that cannot be stopped by outside forces.

Therefore, you should try to minimize your exposure. If possible, avoid being close to an X-ray source, but if that's not possible, use radiation protection.

Depending on the application, it can come in many shapes. For example, you can use LED screens to block out the fluence (flux of photons) that is focused at you. By placing these screens between you and the source, you can significantly reduce this fluence.

The same is true with protective vests that shield you from photons by absorbing them. These vests can include parts made of lead or other high atomic number materials.

So, a person can wearing a protective vest to limit exposure to X-rays.

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so the company hire company B because it pays not more than 85 cents.

Why would you not want to sell a cold pack made with compound x?

1. Technically it depends upon the temperature of your hand: if we assume the body temperature is 37 C then your hand is warmer than the beaker and the beaker will feel cold.

2. This is an endothermic reaction.

3.  If the beaker changes from 25 C to 5 C the energy is lower.

1.5g x (20/5) = 6.0 grams.

Cost of 6.0 g is

$184.04 x (6.0/1000) = about $1.10 each.

its cost = 110 cents

Compound B the same way.

1.0g x (20/2.5) = 8.0 grams.

Cost of 8.0 g is

$97.13 x (8.0/1000) = about $0.777 each.

its cost 77.7 cents.

so the company hire company B because it pays not more than 85 cents.

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The cell potential of an electrochemical cell with the cell reaction  is 1. 607 v.  the maximum electrical work obtainable from this cell when 0. 50 g of al is consumed is - 9.3 × 10⁵ J.

The reaction is given as :

2Al  +  3Zn²⁺  ---->   3Zn   +   2Al³⁺

the maximum electrical work obtainable from this cell:

ΔG = - n FE°cell

where,

maximum electrical work = ΔG

n = no. of transfer electron = 2 × 3 = 6 e⁻

E°cell = 1.607 V

ΔG = - n FE°cell

ΔG = - 6 × 9.65 × 10⁴ ×  1.607

ΔG = - 9.3 × 10⁵ J

Thus the maximum electrical work obtain from this cell is - 9.3 × 10⁵ J.

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