How many atoms of calcium are present in 83.4 g of calcium?

The sodium-potassium pump goes to work after the contraction has occurred in order to repolarize the cells.

The sodium-potassium pump is a pump that functions in transporting sodium ions out of the cell and potassium ions inside the cell.

At the resting membrane potential, the sodium-potassium pump ensures that the interior of the cell is negative relative to outside the cell because three sodium ions are pumped out of the cell for every two potassium ions that are pumped into the cell.

When an action potential reaches the cell, the pump opens and allows sodium ions into the cell thereby depolarizing it. Afterward, the sodium-potassium pump works to repolarize the cell by pumping sodium out and potassium in.

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Answer:

Rubidium Cyanide and Water

Explanation:

The molarity of the barium hydroxide solution is 0.065M.

Molarity is the concentration of a substance in solution, expressed as the number moles of solute per litre of solution.

The molarity of a substance can be calculated using the following formula:

CaVa = CbVb

Where;

According to this question, an aqueous solution of barium hydroxide is standardized by titration with a 0.170 M solution of nitric acid. If 27.2 mL of base are required to neutralize 10.4 mL of the acid, the molarity of the barium hydroxide solution can be calculated as follows:

0.170 × 10.4 = Cb × 27.2

1.768 = 27.2Cb

Cb = 0.065M

Therefore, 0.065M is the molarity of the barium hydroxide solution.

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The reaction as is shown in option E has its enthalpy of reaction not the same as the enthalpy of formation of the product.

The enthalpy of formation is the heat that is evolved or absorbed when a substances is formed from its constituents under standard conditions. We know also that the enthalpy of the reaction is the heat that is evolved or absorbed in the reaction.

In a case where we know that the compound which is obtained in the product is not formed from the substances that are in their standard states, it the follows that the enthalpy of the reaction would not be the same as the enthalpy of formation of the product.

This is so because, the enthalpy of formation of the standard substances is always zero. Given the fact that both Xenon atom and the fluorine gas are pure substances in standard state, their enthalpies of formation are zero thus the enthalpy of formation of the xenon fluoride is the same as the enthalpy of the reaction. Option E.

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Answer:

Below

Explanation:

Mole wt:

cu = 63.546

c x 2 =24

hx6=6

0 x 4 =64    total per mole = 157.546

Number of moles * Avagadro's Number  = number of molecules

    80 / 157.546     *  6.022 x 10^23 = 3.06 x 10^23 molecules

11.29 grams of strontium-ninety had been gift withinside the unique rock pattern in 1933. Strontium- ninety decays to yttrium-ninety, which in flip decays to solid zirconium.

The isotopes of strontium and yttrium emit beta debris as they decay. The launch of radiation throughout this decay manner reasons situation approximately the protection of strontium and all different radioactive substances. Sr-ninety may be inhaled, however ingestion in meals and water is the best fitness situation. Once withinside the body, Sr-ninety acts like calcium and is effectively included into bones and teeth, wherein it may purpose cancers of the bone, bone marrow, and smooth tissues across the bone.

Strontium has a half-existence of 28.8 years. Therefore,

1989 - 1933 = 56years.

fifty six / 28.eight = 1.94 half-lives

Thus, the amount of the radioisotope closing will double for every half-existence elapsed. transferring backwards in time. Therefore, transferring backwards in time through 1.94 times half-lives, the amount closing will double through 1.94 times.

Thus, the quantity closing in 1933 is 3.0 × (1.ninety four)² = 11.29 grams.

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AnswerNegative Partial Charge on: Se, O, O. O-Te is most polar.

Explanation:

O, Se, and Te are all in the same group on the periodic table, which makes this question easier because there is a periodic trend for electronegativity going up and down groups. The more you go down the periodic table, the more shielding affect there is where the electrons closest to the nucleus of an atom block the protons’ positive charge from reaching other electrons. So, O is the most electronegative here, followed by Se, and then Te. So in a bond with O and either of the other two, O will always have a partial negative charge. Se in a bond with Te will also have a partial negative charge, but the difference in electronegativity is biggest between O and Te, and so that is the most polar bond.

According to the electronic configuration and difference in electronegativity, the most polar bond is O-Te.

Electronic configuration is defined as the distribution of electrons which are present in an atom or molecule in atomic or molecular orbitals.It describes how each electron moves independently in an orbital.

Knowledge of electronic configuration is necessary for understanding the structure of periodic table.It helps in understanding the chemical properties of elements.

Elements undergo chemical reactions in order to achieve stability. Main group elements obey the octet rule in their electronic configuration while the transition elements follow the 18 electron rule. Noble elements have valence shell complete in ground state and hence are said to be stable.

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An acetone with a density of 0.7857 g/mL and a mass of 0.3201 lbs will have a volume of 184.796 mL.

What is density?

The density of a substance is a function of its mass and volume. The variables are related to each other, such that:

Density = mass/volume.

Thus, given any two of the 3 variables, the third variable can be calculated by making it the subject of the formula.

Now to the problem at hand. The acetone has a density of 0.7867 g/mL and a mass of 0.3201 lbs. Because the unit of density is g/mL, the mass in lbs first needs to be converted to grams.

1 lb = 453.592 grams

0.3291 lbs = 0.3201 x 453.592

                  = 145.194 grams

Now, let's make volume the subject:

volume = mass/density

             = 145.194/0.7857

             = 184.796 mL

In summary, acetone with a density of 0.7857 g/mL and a mass of 0.3201 lb will have a volume of 184.796 mL.

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The correct balanced chemical equation is

[tex]\rm FeCl_2(aq) + 3NaOH(aq) \rightarrow Fe(OH)_3(s) + 3NaCl(s)[/tex]. Hence option A is correct.

Chemical equation is defined as the use of symbols and chemical formulas to represent a chemical reaction symbolically. Chemical equations give information about a compound's chemical make-up. The ratios in which the component parts combine to form the compound are also represented by them.

Balanced chemical equation is defined as entails giving the reactants and products stoichiometric coefficients. In a chemical equation, the number of atoms in the reactants and the number of atoms in the products must balance out.

Thus, the correct balanced chemical equation is

[tex]\rm FeCl_2(aq) + 3NaOH(aq) \rightarrow Fe(OH)_3(s) + 3NaCl(s)[/tex]. Hence option A is correct.

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Answer:

copper

Explanation:

First, write down the reaction and notice the ratio of moles of which the reactants react.

the equation (i'm too lazy to write states of matter and since it doesnt matter in this problem i'm not going to. it is balanced, however) is:
Cl2 + Cu -> CuCl2

as you can see, one mole of chlorine gas reacts with one mole of copper.

since we have 75 moles of copper but only 70 moles of chlorine gas, after everything has been reacted we would expect 5 moles of copper to be left over. so, copper is the the reactant which is in excess

The energy of the eight shell of the hydrogen atom is obtained 0.2 eV

We know that from the Bohr model, the electrons that are in an atom can be arranged in energy levels. The energy levels of the atom are arranged in such a way that the levels that are lowest in energy are found nearer to the nucleus and the energy of the shells continue to increase outwards.

Thus, the energy of the eight shell would be much more than the energy of the first shell. Let us consider the formula;

E = - 13.6Z^2/n^2

Where;

Z = atomic number of the atom

n = The shell where the electron is

Thus;

E = - 13.6 * 1/8^2

E = -0.2eV

Thus the energy that an electron that we can find in the shall that has n = 8 would have the energy that is equivalent to 0.2eV.

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The molecular formula for Epsom salt is [tex]{ \blue{ \underline{ \tt{MgS O_{4} .7H_{2}O}}}}[/tex]

The empirical formula of the compound (metal bromide) formed when 20.90 grams of chromium is heated in the presence of excess bromine is CrBr₂

First, we shall determine the mass of bromine in the compound. This is illustrated below

Mass of bromine = (Mass of compound) - (Mass of chromium)

Mass of bromine = 85.14 - 20.90

Mass of bromine = 64.24 grams

Haven obtained the mass of the bromine, we shall determine the empirical formula of the metal bromide. This is shown below:

Divide by their molar mass

Cr = 20.90 / 52 = 0.4

Br = 64.24 / 79.9 = 0.8

Divide by the smallest

Cr = 0.4 / 0.4 = 1

Br = 0.8 / 0.4 = 2

Thus, from the above calculation, the empirical formula of the metal bromide is CrBr₂

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State of matter of both substance will be liquid at 115C.

A substance-A substance's melting point is 100 degrees Celsius. Thus, liquid material A will arise from temperatures over 100 degrees. Since material A is liquid at 115 degrees Celsius, the particles are free to migrate and glide over one another.

B Substance-It has a  freezing point of 110 degrees Celsius. This signifies that substance B will exist in a liquid condition at any temperature greater than 110 °C. In a liquid condition, the components of solution B will also be sufficiently mobile to travel past one another.

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Answer:

Explanation:

Coffee is a drink prepared from roasted coffee beans. Darkly colored, bitter, and slightly acidic, coffee has a stimulating effect on humans, primarily due to its caffeine content. It is the most popular hot drink in the world. Seeds of the Coffea plant's fruits are separated to produce unroasted green coffee beans.

Answer:

The answer is 10.507 KJ

Explanation:

The formula you need to use for this question is MC(delta)T:

M=Mass ( 175g)

C=Specific Heat ( depends on the element, copper=0.38 j/g.k )

and T= Temperature, where you find the change in temperature by minusing the final T with the initial T.  

so, (175g)(0.38)(184-26)= 10,507 J

since we need the answer in KJ divide 10,507 by 1000

10,507/1000 = 10.507 KJ

Energy, in kJ, is required to completely melt 20.0 g of ice initially at -45.0 °C is 4.147kJ

Energy is the capacity for doing work

Here given data is

Mass = 20.0 g

Temprature = -45.0°C

Molar heat of fusion of ice = 6.02 kj/mol

We have to calculate energy in kJ = ?

Then q = n×ΔH

q = heat

n = number of moles

ΔH = enthalpy

First we calculate the m=number of moles

Number  of moles = mass / molar mass

Number  of moles =  12.4 g/ 18 g/mol

Number  of moles =  0.69 mol

Now put this value in formula

q = n × ΔH

q =  0.69 mol×6.02 kj/mol

q = 4.147kJ

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Ammonia is added to the test solution in a penny-earned lab to test the behavior of the reaction on a penny.

The cause of this Penny Lab is to determine how soap on a penny affects the figure of drops that it can hold, compared with a penny with no soap. Water molecules are impelled to each other, so they tend to try to stick together (cohesion). When a copper penny is heated in a solution of sodium hydroxide solution assorted with zinc dust, small amounts of zinc dissolve into the surface of the penny. This causes the penny to look silver already there is now a layer of zinc over the outside of the penny.

So we can conclude that  In this activity you will see that soap decreases the surface tension of water by satiuate water droplets on top of a penny.

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Answer:

7

Explanation:

valence electrons are the electrons in the outer shell

The structural formula of the compounds from the task given above are as follows:

Methane, CH4: CH4CH4

Ethane, C2H6: (CH3)2

Propane, C3H8: CH3CH2CH3

Pentane, C5H12: CH3(CH2)3CH3

Hexane, C6H14: CH3(CH2)4CH3

A structural formula of an organic compound simply represent the various locations of atoms and bonds which makes up the organic compound.

It explains the exact point to fix bonds and atoms when writing the structural formula of a compound. That being said, organic compound simply refers to those classes of chemical compounds containing carbon and hydrogen.

They are different homologous families including the alkanes, alkenes, alkaynes, alkanols, alkanoates, alkanals and so on and so forth.So therefore, it can be deduced from the simple explanation above that the structural formula of compounds also enables us to clearly give the correct nomenclature of the compound.

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The concentration of the specie is obtained as  0.79 M.

We know that a buffer is a solution that is resistant to changes in acidity and alkalinity. Now, we know that we have the following information;

pH = 10.00

Concentration of base = 0.18 M

Kb = 4.4 x 10 -4

Hence;

pOH = 14 - 10.00 = 4

pKb = -log( 4.4 x 10 -4)  3.36

Using the formula;

pOH = pKb + log [A-/AH]

4 = 3.36 + log[A-/0.18]

4 - 3.36 = log[A-/0.18]

Antilog(4 - 3.36) = [A-/0.18]

A- = Antilog(4 - 3.36) * 0.18

A- = 0.79 M

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The number of moles of the KClO₃ required to produce 5.15 moles of KCI is equal to 5.15 moles.

A mole can be described as a standard unit that is utilized to calculate the huge number of atoms, molecules, ions, or other particular particles. The mass of the 1 mole of any element is known as atomic mass and that of any compound is known as molar mass.

The number of units present in one mole is equal to 6.023 × 10 ²³ which is known as Avogadro’s constant or Avogadro’s number.

Given the chemical reaction of the decomposition of KClO₃ is :

2 KClO₃ ⟶  2KCl  +  3O₂

Given, the number of moles of KCl = 5.15 moles

As from the given  decomposition chemical reaction,

Two moles of the KCl are produced from moles of KClO₃ = 2

5.15 moles of  KCl are produced from KClO₃ = 5.15 mol

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The food and agriculture industries' most complete carbon and net-zero route planner.

Coal, toxic gases, and crude oil—which are all used as fuel—are utilized to manufacture gasoline. It is employed to create a variety of products, such as polymers and steel, which is an alloy made of iron and carbon. Even black ink for printing and painting is produced with it.

The majority of carbon is kept in reservoir, or sinks, such rocks and sediments; the remaining portion is kept in the atmosphere, the oceans, and living things. Through the respiration of both plants and animals, carbon is returned to the atmosphere.

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The volume of gas produced at 18 degrees Celsius 34.7 g of carbon dioxide gas creates of 623 mmHg is 0.03 L

The ideal gas equation is as follows;

PV=nRT

P,V,n,R,T are pressure, volume, number of moles, gas constant and temperature respectively

Substituting the values, we get

623xV=34.7/44x0.0821X291

623V=0.78X23.8911

623V=18.635

V=0.03 L

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Answer:

If the dad has brown eyes, and the mom has blue eyes, then the kid will have blue eyes. If the dad has blue eyes and the mom has brown eyes, the kid will have brown eyes.

Explanation:

Answer: what the person above me said

Explanation:

M+1 peak is a small line 1 m/z unit to the right of the main molecular ion peak and the small peak is called as M+1 peak

Mass spectrum is a analytical tool useful for measuring the mass to charge ratio means m/z of one or more molecules present in a sample and these measurement can often be used to calculate the exact molecular weight of the sample components as well and M+ peak is usually the highest intensity peak in the cluster of peak at highest m/z and M+1 peak is a small line 1 m/z unit to the right of the main molecular ion peak and the small peak is called as M+1 peak

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Lewis structure is a very simplified representation of the valence shell electron in a molecule

For Lewis structure of acetone then calculate the total number of valence electron for the acetone molecule and after determining how many valence electron there are in acetone and place them around the central atom to complete the octet and there are total 24 valence electron in the Lewis structure for acetone and it is used to show how electron are arranged around individual atom in molecule and electron are shown as dot or for bonding electron as a line between the  two atom

The Lewis structure of acetone are shown below

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Oxygen is inhaled to the lungs, and brought into the blood, which is known as diffusion . Our bodies exchange the oxygen for carbon dioxide, which is called respiration .The carbon dioxide is forced out of lungs by increasing the pressure of the lungs.

Respiration can simply be defined as the exchange of gases between an organism and its environment. In order words, it refers to the breathing in of oxygen and breathing out of carbon dioxide.

That being said, some few categories, levels or classes of respiration are known in living organisms:

So therefore, we can now confirm from the simple note given above that when substances such as oxygen moves from a region where it is highly concentrated to a region where it is of a lesser amount, it is known as diffusion.

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