Can someone help me with this ASAP

Answer:

B. It has a stable octet and is unreactive.

Explanation:

s orbital contains 2 electrons and p contains 6. When the outermost energy level of an element has a total of 8 electrons we call it stable octet and it is unreactive. Therefore the answer is B

Answer:

B.

Explanation:

For example the element with configuration

1s2 2s2 2p6 which is Neon, an inert.

It has a stable 8 electrons in its outermost shell which makes it stable.

When reacting with an atom of fluorine, an atom of lithium will lose an electron and become a lithium ion.

Answer: Option D

Explanation:

Most of the chemical reactions or diffusion occurs by transfer of electrons among the elements combining to form a material. So depending on the type of bonding existed in any molecule, the strength of the bonding and its directionality can be measured.

Basically two or mole elements combine to form a compound and in this process, one of the element need to give some amount of electron to the other elements. And this transfer of electrons can be known from their oxidation state. As the element is giving or taking an electron from/to other element, that corresponding donating element and receiving element will be termed as ions from atoms.

So, the element which has the tendency to give electron easily will form positive ions and similarly, the element which is known for attracting electrons towards itself is termed as negative ions. So in this case, on reaction of fluorine with lithium, the lithium will lose an electron and become a lithium ion.

Explanation:

An alpha particles is basically a helium nucleus and it contains 2 protons and 2 neutrons.  

Symbol of an alpha particle is [tex]^{4}_{2}\alpha[/tex].

A beta particle is a particle with a negatively charged electron. Symbol of a beta particle is [tex]^{0}_{-1}\beta[/tex].

According to the given question, the decay series chart along with reaction equation are as follows.

(a)  Lead-214 changes to bismuth-214.

        [tex]^{214}_{82}Pb \rightarrow ^{214}_{83}Bi + ^{0}_{-1}e[/tex]

(b)  Bismuth-214 changes to polonium-214.

        [tex]^{214}_{83}Bi \rightarrow ^{214}_{84}Po + ^{0}_{-1}e[/tex]

(c)  Polonium-214 changes to lead-210.

         [tex]^{214}_{84}Po \rightarrow ^{210}_{82} + ^{4}_{2}He[/tex]

Therefore, we can conclude that proper order of nuclear particle emission is beta, beta, alpha.

Answer:Se-2, Cl-1, Cs-1, P-1

Explanation:

Let us consider the groups the elements belong to

Se- group 16, ns2np4- two unpaired valence electrons

Cl- group 17, ns2np5- 1 unpaired electron

Cs-group 1, ns1- one unpaired electron

P-group 15- ns2np3- three unpaired valence electrons

Chlorine has 1 unpaired electron, selenium has 2, cesium has 0, and phosphorus has 3.

In chlorine, there is 1 unpaired electron.

In selenium, there are 2 unpaired electrons.

In cesium, there are 0 unpaired electrons.

In phosphorus, there are 3 unpaired electrons.

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Answer:

Reaction 1 is balanced but 2 is not balanced , the balance equation are :

1. [tex]CH_{3}COOH(aq) + NaHCO_{3}(aq)\rightarrow CO_{2}(g) + H_{2}O(l) + CH_{3}COONa(aq)[/tex]

2.[tex]CaCl_{2}(aq) + 2NaHCO_{3}(aq)\rightarrow CaCO_{3}(aq) + H_{2}O(l) + 2NaCl(aq) + H_{2}O(aq)[/tex]

Explanation:

Balanced Equations : These are the equation which follows the law of conservation of mass .

The total number of atoms present in reactant is equal to total number of atoms present in product.

1. [tex]CH_{3}COOH(aq) + NaHCO_{3}(aq)\rightarrow CO_{2}(g) + H_{2}O(l) + CH_{3}COONa(aq)[/tex]

This is acid - base type reaction where

[tex]CH_{3}COOH(aq)[/tex] act as Acid

[tex] NaHCO_{3}(aq)[/tex] act as weak base

Reactant :[tex]CH_{3}COOH(aq)[/tex] ,[tex]NaHCO_{3}[/tex]

Number of atoms of :

C = 2 ([tex]CH_{3}COOH(aq)[/tex]) + 1 ([tex]NaHCO_{3}[/tex])

   = 2 + 1

   = 3

H  = 4([tex]CH_{3}COOH(aq)[/tex]) + 1 ([tex]NaHCO_{3}[/tex])

     = 4 + 1

       5

O = 2([tex]CH_{3}COOH(aq)[/tex]) + 3 ([tex]NaHCO_{3}[/tex])

    = 5

Na = 1 ([tex]NaHCO_{3}[/tex])

     = 1

Product :  [tex]CO_{2}(g)[/tex],[tex]H_{2}O(l)[/tex] , [tex]CH_{3}COONa(aq)[/tex]

Number of atoms :

C = 1([tex]CO_{2}(g)[/tex]) + 2([tex]CH_{3}COONa(aq)[/tex])

   = 1 + 2

   = 3

H = 2([tex]H_{2}O(l)[/tex]) + 3([tex]CH_{3}COONa(aq)[/tex])

   = 2 + 3

   = 5

O = 1([tex]H_{2}O(l)[/tex]) + 2([tex]CH_{3}COONa(aq)[/tex])

        +2([tex]CO_{2}(g)[/tex]

    = 1 + 2 + 2

    = 5

Na = 1([tex]CH_{3}COONa(aq)[/tex]

     = 1

Number of Na =1 , C = 3 , H= 5 and O =5 in both reactant and product , so it is a balanced reaction

2.[tex]CaCl_{2}(aq) + 2NaHCO_{3}(aq)\rightarrow CaCO_{3}(aq) + H_{2}O(l) + 2NaCl(aq) + CO_{2}(g)[/tex]

This is double displacement reaction .

Check the balancing in both reactant and products should be :

Na = 2

H = 2

Ca = 1

C = 2

O = 6

Cl = 2

Answer: Option (c) is the correct answer.

Explanation:

Atomic number of sodium is 11 and its electronic configuration is [tex]1s^{2}2s^{2}2p^{6}3s^{1}[/tex]. When sodium loses one electron then it will attain +1 charge and its electronic configuration will be as follows.

[tex]Na^{+}[/tex] : [tex]1s^{2}2s^{2}2p^{6}[/tex]

Atomic number of fluorine is 9 and its electronic configuration is [tex]1s^{2}2s^{2}2p^{5}[/tex]. When fluorine gains an electron then it acquires -1 charge and its electronic configuration is as follows.

[tex]F^{-}[/tex] : [tex]1s^{2}2s^{2}2p^{6}[/tex]

Atomic number of aluminium is 13 and its electronic configuration is [tex]1s^{2}2s^{2}2p^{6}3s^{2}3p^{1}[/tex]. When aluminium loses its valence electrons then it acquires +3 charge and its electronic configuration is as follows.

[tex]Al^{3+}[/tex] : [tex]1s^{2}2s^{2}2p^{6}[/tex]

Thus, we can conclude that the listing for aluminum is correct.

Final answer:

The correct listing according to the electron structures of atoms and ions is for aluminum, which has an atomic structure of 1s²2s²2p¶3s²3p¹ and as an ion it has a structure of 1s²2s²2p¶ with a net charge of +3.

Explanation:

The student has asked to identify the correct listing of electron structure of an atom and the resulting ion, as well as the net ion charge for sodium, fluorine, and aluminum. In the case of sodium (Na), the atom has an electronic structure of 1s²2s²2p¶3s¹ and the sodium ion will have a structure of 1s²2s²2p¶ with a net charge of +1 after losing one valence electron. For fluorine, the atom has a structure of 1s²2s²2p¶4 and as a fluoride ion, it gains one electron to complete its valence shell, resulting in 1s²2s²2p¶ and a -1 charge. Lastly, aluminum (Al) has an electronic structure of 1s²2s²2p¶3s²3p¹. When it forms an ion, it loses three electrons becoming 1s²2s²2p¶ with a net charge of +3. Based on this information, choice c, the listing for aluminum is correct.

Answer: atoms

Explanation:

All matter is made up of smaller indivisible particles called atoms. These atoms are the smallest units of matter ACCORDING to the Dalton's Atomic theory.

Molecules are combined atoms, while cells and phospholipids are complex combination of atoms.

Therefore, atoms is the answer

To find the partial pressure of Ne in the sample, subtract the sum of the partial pressures of the other gases from the total pressure.

To find the partial pressure of Ne in the sample, we need to first determine the partial pressures of all the gases in the mixture. The total pressure in the container is 1355 mm Hg. The partial pressures given are: He (43 mm Hg), Ar (835 mm Hg), and Xe (111 mm Hg).

To find the partial pressure of Ne, we need to subtract the sum of the partial pressures of the other gases from the total pressure.

Partial pressure of Ne = Total pressure - (Partial pressure of He + Partial pressure of Ar + Partial pressure of Xe).

The question is incomplete, here is a complete question.

Categorize each reaction into types of chemical reactions.

(1) [tex]NaCl(aq)+AgNO_3(aq)\rightarrow AgCl(s)+NaNO_3(aq)[/tex]

(2) [tex]H_2SO_4(aq)+2LiOH(aq)\rightarrow 2H_2O(l)+Li_2SO_4(aq)[/tex]

(3) [tex]HCl(aq)+(NH_4)_2S(aq)\rightarrow H_2S(g)+2NH_4Cl(aq)[/tex]

(4) [tex]Mg(s)+Cu(NO_3)_2(aq)\rightarrow Mg(NO_3)_2(aq)+Cu(s)[/tex]

Answer :

(1) Precipitation reaction

(2) Neutralization reaction

(3) Double-displacement reaction

(4) Single replacement reaction

Explanation :

(1) The balanced chemical reaction is:

[tex]NaCl(aq)+AgNO_3(aq)\rightarrow AgCl(s)+NaNO_3(aq)[/tex]

This reaction is a precipitation reaction in which an insoluble salt formed when two aqueous solutions are combined.  The insoluble salt that settle down in the solution is known an precipitate.

(2) The balanced chemical reaction is:

[tex]H_2SO_4(aq)+2LiOH(aq)\rightarrow 2H_2O(l)+Li_2SO_4(aq)[/tex]

This is a neutralization reaction in which an acid react with a base react to give salt and water as a product that means it reacts to give a neutral solution.

(3) The balanced chemical reaction is:

[tex]HCl(aq)+(NH_4)_2S(aq)\rightarrow H_2S(g)+2NH_4Cl(aq)[/tex]

The given reaction is a double-displacement reaction in which the cation of two reactants molecule exchange their places to give two different products.

(4) The balanced chemical reaction is:

[tex]Mg(s)+Cu(NO_3)_2(aq)\rightarrow Mg(NO_3)_2(aq)+Cu(s)[/tex]

This reaction is a single replacement reaction in which the the more reactive element replace the less reactive element.

Answer:

Explanation:

According to this. Let's analize the possible products a, b and c.

First, the problem states that we have 2 eq. of base, For this case, let's assume it's KOH. Now, As we are doing a reaction with base, means that this reaction can only take places under conditions of SN2 and E2, a fast reaction that is taking place in only 1 step.

With this in mind, let's analyze product a. This states that it has two sp hybridized carbon, in other words, a triple bond between two carbons. So the product is with no doubt, an alkyne.

Product b has only one sp hybridized carbon, which means that this carbon should cannot be an alkyne because we need two carbon atoms. The only way to have one atom of C sp hybridized, is with two double bonds, so product b would have to a alkene with two double bonds.

Product c do not have sp hybridized carbon, therefore, it only has two double bonds in two different Carbon atoms, so it's another alkene with two double bonds, but in two different atoms of carbon.

Picture attached show the product a, b and c. Hope this can help

In a reaction involving 2,3-dibromobutane and a base, three products with distinct arrangements of π bonds and sp hybridized carbons are formed. Given that Product B has one sp hybridized carbon, it is likely to be 2-butyne.

In the reaction of 2,3-dibromobutane with two equivalents of a base, the base will act as a nucleophile and attack the carbon atoms bound to the bromine atoms. This will then form three products, each with two new π bonds. Given that Product B has one sp hybridized carbon atom, it is likely that this product is 2-butyne. 2-butyne has one in which both are on the same side producing a cis- configuration, and one in which they are on opposite sides producing a trans- configuration.

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Answer:

This question is incomplete. But the completed question is below

A sample of helium gas is in a closed system with a movable piston. The volume of the  gas sample is changed when both the temperature and the pressure of the sample are increased.  Where the initial temperature of the gas is 200K, initial pressure is 2.0 atm, initial volume is 500 mL, the final temperature is 300K and the final pressure of the gas sample is 7.0 atm.

What is the correct numerical setup for calculating the final volume of the helium gas sample?

P₁V₁/T₁ = P₂V₂/T₂ will be used in calculating the final volume.

And the final volume is 214.29 mL

Explanation:

The general gas equation will be used to calculate the final volume. The general gas equation is

P₁V₁/T₁ = P₂V₂/T₂

From the question

P₁ = 2.0 atm

T₁ = 200K

V₁ = 500 mL

P₂ = 7.0 atm

T₂ = 300K

V₂ = unknown

Hence, we have

2 × 500/200 = 7 × V₂/300

V₂ = [tex]\frac{2 * 500 * 300}{200 * 7}[/tex]

V₂ = 214.29 mL

The final volume of He gas sample has been 214.285 mL.

Helium has been assumed to be an ideal gas. The final volume of the gas with an increase in pressure has been given by:

[tex]\dfrac{P_1V_1}{T_1}=\dfrac{P_2V_2}{T_2}[/tex]

Where, the initial pressure of gas, [tex]P_1=2\;\text{atm}[/tex]

The final pressure of gas, [tex]P_2=7\;\text{atm}[/tex]

The initial volume of gas, [tex]V_1=500\;\text{ml}[/tex]

The initial temperature of gas, [tex]T_1=200\;\text K[/tex]

The final temperature of gas, [tex]T_2=300\;\text K[/tex]

Substituting the values for the final temperature of He, [tex]V_2[/tex]:

[tex]\dfrac{2\;\times\;500}{200}=\dfrac{7\;\times\;V_2}{300}\\\\\dfrac{2\;\times\;500}{200}\;\times\;\dfrac{300}{7} = V_2\\\\V_2=214.285\;\rm ml[/tex]

The final volume of He gas has been 214.285 mL.

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B

The emission spectrum of an element is identical to its absorption spectrum.

Explanation:

This is because a quantum leap  of an electron of an atom from one lower energy level to a higher one results in the absorption of a specific wavelength of electromagnetic radiation. When the electron leaps back to the lower energy level, it releases the same wavelength of electromagnetic radiation. This is according to Bohr's theory. Every atom has a signature absorption and emission spectra that are used to identify it.

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Wind speed is unrelated to the amount of water vapour in the sample of moist air.

Answer: Option E

Explanation:

As the sample of moist air is combination of water vapour mixed with air molecules, there will be no generation of wind in the moist air. But there will be change in the pressure and temperature when water vapours or moisture mixes with air molecules.

As water is having high density compared to air molecules, the pressure will be changed in moist air. So, the amount of water vapour in the moist air sample can measure by relative difference in pressure, temperature, vapour density and volume with air molecules in general.

Answer:

Answer E

Explanation:

Answer:

[tex]1.7742\times 10^{-3} mol/L[/tex] is the molar concentration of Cu(II) ions in the unknown solution.

Explanation:

Using Beer-Lambert's law :

Formula used :

[tex]A=\epsilon \times C\times l[/tex]

where,

A = absorbance of solution

C = concentration of solution

l = length of the cell =

[tex]\epsilon[/tex] = molar absorptivity of solution

A Beer's law plot is between absorbance and concentration.

[tex]\frac{A}{c}=Slope(m)=\epsilon\times l[/tex]

We have:

A = 0.55

The slope of the Beer's law plot = m = 310 L/mol

So, the concentration of the solution is:

[tex]c=\frac{A}{m}=\frac{0.55}{310 L/mol}=1.7742\times 10^{-3} mol/L[/tex]

[tex]1.7742\times 10^{-3} mol/L[/tex] is the molar concentration of Cu(II) ions in the unknown solution.

Using Beer's law and the given slope and absorbance values, the molar concentration of Cu2+ in the solution is approximately 1.77 * [tex]10^{-3[/tex] M.

Beer's law, also known as the Beer-Lambert law, establishes a linear relationship between the absorbance of a species in a solution and its concentration. The equation for Beer's law is A = εlc, where A is absorbance, ε is the molar absorptivity (given by the slope in this case), l is the path length (assumed to be 1 cm here), and c is the concentration. In your case, the slope is 310 L/mol, and you have measured an absorbance of 0.55.

To find the concentration of Cu2+ in the solution, we rearrange the Beer's law equation to c = A / εl. Substituting in your values, we get c = 0.55 / (310 L/mol * 1 cm), which simplifies to c = 0.00177 mol/L or 1.77 *  [tex]10^{-3[/tex]  M. So the molar concentration of Cu2+ in the unknown solution is approximately 1.77 *  [tex]10^{-3[/tex]  M.

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Answer: One (1) electron

Explanation:

Lithium is a group 1 element with an atomic number of 3. Thus, it has just 3 electrons and its electronic configuration is 1s2, 2s1

To become lithium ion salts, it gives off its lone electron thereby becoming Li+ with configuration of 1s2 with just 2 electrons left.

So, Li atom loses only ONE ELECTRON to become an ion

Answer:

A

Explanation:

Chlorofluorocarbons generally abbreviated as CFCs are a group of organic chemicals used in several household and industrial materials and are responsible for global warming and ozone depletion.

Global warming is the general increase in the atmospheric temperature of the earth continually over the years. It is a direct consequence of climate change which is caused by the continuous release of green house gases into the atmosphere which trap radiated heat from the sun.

Ozone depletion involves anthropogenic activities which lead to decreasing the natural spread of the ozone layer which prevents the direct contact between the sun UV radiation and the earth.

CFCs are implicated in both cases as they are responsible for the two I.e they cause global warming and also deplete the ozone layer. Years back they are basically used in most aerosol cans like perfumes spray, insecticide spray etc. However as a result of the increased knowledge of their dangers, there had been legislations which had cut down on their continuous usage with alternatives being used

Answer:

The answer to your question is Aluminum

Explanation:

Number of clues

1.- If this element has 3 rings in its Bohr model, we are looking for and element located in the third period of the periodic table.

For example Sodium, Magnesium, Aluminum, Silicate, Phosphorus, Sulfur, Chlorine and, Argon.

2.- It makes three bonds to become stable, then we are looking for and element located in the third group like

 Boron, Aluminum,  Gallium, Indium, etc

Conclusion

The element that has both characteristics is Aluminum

Answer:

0

Explanation:

There are no unpaired electrons in the given element. It must be noted that for the atom above, we have even numbered electrons. The total electron we are having here is 18.

Now, we must also know that while the s orbital is not degenerate, the P orbital is degenerate. What this mean is that the p orbital is broken down into three different sub orbitals which is the Px , Py and Pz. Hence we can see that there are 6 electrons to enter into the P orbital too.

We can see that all the S orbitals have been completely filled with two electrons alike each. This is also the case for the P orbital as the 3 suborbitals take in 2 each to give a total of six

The number of unpaired electrons in the atom represented by the electron configuration - 1s² 2s² 2p⁶ 3s² 3p⁶ is zero.

Electronic configuration refers to the arrangement of electrons within the atomic orbitals of an atom. It provides a description of how electrons are distributed among the various energy levels and sublevels within an atom.

The electronic configuration is typically represented using a notation that indicates the principal energy level (n) and the sublevel (s, p, d, f) in which the electrons are located. Each sublevel can hold a specific number of electrons: s sublevel holds 2 electrons, p sublevel holds 6 electrons, d sublevel holds 10 electrons, and f sublevel holds 14 electrons.

To determine the number of unpaired electrons, we need to examine the electron configuration in terms of its orbital filling. In this case, all the orbitals up to the 3p sublevel are completely filled with electrons. Neon is an example of a noble gas with a full valence shell, making it stable and unreactive.

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Explanation:

The longest wavelength of light with enough energy to break the Cl-Cl bond = 495 nm = [tex]495\times 10^{-9} m[/tex]

1) The frequency of the light:

[tex]\lambda =495\times 10^{-9} m[/tex]

[tex]\nu=\frac{c}{\lambda }[/tex]

c = speed of light= [tex]3\times 10^8 m/s[/tex]

[tex]\nu=\frac{3\times 10^8 m/s}{495\times 10^{-9} m}[/tex]

[tex]=6.0606\times 10^{14) s^{-1}[/tex]

The frequency of the light is [tex]6.0606\times 10^{14) s^{-1}[/tex].

2)The energy of a photon of the light:

The energy of the photon is given by : E

[tex]E=h\nu [/tex]

h =  Planck's constant = [tex]6.626\times 10^{-34} J/s[/tex]

[tex]E=6.626\times 10^{-34} J/s\times 6.0606\times 10^{14) s^{-1}[/tex]

[tex]=4.016\times 10^{-19} J[/tex]

The energy of a photon of the light is [tex]4.016\times 10^{-19} J[/tex].

3) The minimum energy of the Cl-Cl bond :

To break single bond of Cl-Cl bond we need energy E= [tex]4.016\times 10^{-19} J[/tex]

1 mole = [tex]N_A=6.022\times 10^{23} mol^{-1} [/tex]

So, in order to break 1 mole of Cl-Cl bond we will need:

[tex]E\times N_A=4.016\times 10^{-19} J\times 6.022\times 10^{23} mol^{-1} [/tex]

[tex]=241,828.92 J/mol=241,828.92\times 0.001 kJ/mol=241.83 kJ/mol[/tex]

The minimum energy of the Cl-Cl bond is 241.83 kJ/mol.

The frequency of the light radiation has been 6.0606 × [tex]\rm 10^1^4[/tex] /sec. The energy of the light photon has been 4.016 × [tex]\rm 10^-^1^9[/tex] J. The minimum energy in the Cl-Cl bond has been 241.8292 kJ/mol.

(1) The frequency can be defined as the number of times the wave has been repeated, while the wavelength has been defined as the distance of one wave.

The frequency of the wave in the air can be given as:

Frequency = [tex]\rm \dfrac{speed}{wavelength}[/tex]

Frequency of 495 nm wavelength has been :

Frequency = [tex]\rm \dfrac{3\;\times\;10^8\;m/sec}{495\;\times\;10^-^9\;m}[/tex]

Frequency = 6.0606 × [tex]\rm 10^1^4[/tex] /sec

The frequency of the light radiation has been 6.0606 × [tex]\rm 10^1^4[/tex] /sec.

(2) The energy of the light photon has been given by:

Energy = Plank's constant × Frequency

Energy = 6.626 × [tex]\rm 10^-^3^4[/tex] J/s ×  6.0606 × [tex]\rm 10^1^4[/tex] /sec

The energy of the photon = 4.016 × [tex]\rm 10^-^1^9[/tex] J.

The energy of the light photon has been 4.016 × [tex]\rm 10^-^1^9[/tex] J.

(3) The minimum energy of Cl-Cl bond has been given by:

The energy for 1 photon = 4.016 × [tex]\rm 10^-^1^9[/tex] J.

The energy for 1 mole of Cl-Cl has been the minimum energy for breaking Cl-Cl bond.

1 mole = 6.023  × [tex]\rm 10^2^3[/tex] atoms

Energy for Cl-Cl bond has been =  4.016 × [tex]\rm 10^-^1^9[/tex] J ×  6.023  × [tex]\rm 10^2^3[/tex] atoms

Energy for Cl-Cl bond has been = 241,828.92 J/mol

Energy for Cl-Cl bond has been = 241.8292 kJ/mol.

The minimum energy in the Cl-Cl bond has been 241.8292 kJ/mol.

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Answer:

The final concentration of KCl is 4%

Explanation:

This is a solution with KCl and water.

12% it's a way of concentration that indicates, that in 100 mL of solution, we have 12 g of solute.

If we add 200 mL to this solution, we also have 12 g of solute but now, we have to calculate the new concentration.

New volume = 100 mL + 200 mL → 300 mL

Let's make a rule of three

In 300 mL we have 12 g of solute

In 100 mL we have    (100 .12) / 300 = 4

Answer:

Which are positive?  D.

Which are negative? A. B. C.

Explanation:

Generally, entropy can be defined as the degree of randomness of a system. The entropy of any system increases with an increase in the number of moles of the system. Entropy also increases when there is a change of state from solid to liquid or liquid to gas. Therefore for the systems in the given question:

A pond freezes in winter

The degree of disorderliness decrease because there is a change of state from liquid to solid. Thus, ΔSsys is negative.

Atmospheric CO2 dissolves in the ocean

There is also decrease in randomness, thus, ΔSsys is negative.

An apple tree bears fruit

There is also decrease in randomness, thus, ΔSsys is negative.

A pond freezes in winter, atmospheric CO2 dissolves in the ocean, and an apple tree bears fruit are negative changes in Delta S.

Delta S is a measurement used in thermodynamics to calculate the modifications in the level of entropy.

In conclusion, a pond freezes in winter, atmospheric CO2 dissolves in the ocean, and an apple tree bears fruit are negative changes in Delta S.

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Answer:

B. CaCl + LiCO3 yields CaCO3 + LiCl is not correct

It should be CaCl2 + Li2CO3  → 2LiCl + CaCO3

Explanation:

For a reaction to be double displacement reaction there are two things we need to look for

1) There must be an interchange of the group of ions

2) The reactants must dissolve in water to release ions

A. 2RbNO3 + BeF2 yields Be(NO3)2 + 2RbF

2Rb+ + NO3- + Be^2+ + 2F- → Be(NO₃)₂ + 2RbF

This is correct

B. CaCl + LiCO3 yields CaCO3 + LiCl

This is not correct

The correct equation is:

CaCl2 + Li2CO3  → Ca2+ + 2Cl- + 2Li+ + CO3^2-  → 2LiCl + CaCO3

C. Na3PO4 + 3KOH yields 3NaOH + K3PO4

3Na+ + PO4^3- + 3K+ + 3OH- → 3NaOH + K3PO4

This is correct

D. 2MgI2 + Mn(SO3)2 yields 2MgSO3 + MnI4

2Mg^2+ + 4I- + Mn^4+ + 2SO3^2- → 2 MgSO3 + MnI4

This is correct

Explanation:

A chemical reaction is defined as the reaction in which bonds between the reactants either break or form which leads to the formation of a new substance.

For example, [tex]2Li + Cl_{2} \rightarrow 2LiCl[/tex]

So, when we drop a sodium metal into water then it produces a frizzing sound which shows the metal is reacting with water.

We know that when two aqueous solutions chemically react with each other then it may lead to the formation of an insoluble substance which is known as precipitate.

This means that formation of a precipitate is also a chemical reaction.

Thus, we can conclude that following are the statements which show evidence for a chemical reaction.

Answer:

(a) 4 %; (b) 5 %

Explanation:

We need a Cu-Ag phase diagram to answer these questions (see diagram). Yours may differ slightly from the one I used.

(a) Cu in Ag

The horizontal red line  at 700 °C cuts the right-hand solvus at about 4 % Ag-96 % Cu.

At this point, copper is in equilibrium with the eutectic.

At 700 °C, the maximum solubility of Cu is about 4 % by mass.

(b) Ag in Cu

The horizontal red line  at 700 °C cuts the left-hand solvus at about 5 % Cu-95 % Ag.

At this point, silver is in equilibrium with the eutectic.

At 700 °C, the maximum solubility of Ag is about 5 % by mass.

In this exercise we have to calculate the maximum of each component in the solution:

a) 4%

b) 5%

We need a Cu-Ag phase diagram to answer these questions (see diagram). Yours may differ slightly from the one I used.

(a) Cu in Ag

The horizontal red line  at 700 °C cuts the right-hand solvus at about 4 % Ag-96 % Cu.

At this point, copper is in equilibrium with the eutectic.

At 700 °C, the maximum solubility of Cu is about 4 % by mass.

(b) Ag in Cu

The horizontal red line  at 700 °C cuts the left-hand solvus at about 5 % Cu-95 % Ag.

At this point, silver is in equilibrium with the eutectic.

At 700 °C, the maximum solubility of Ag is about 5 % by mass.

Learn more: brainly.com/question/16461028

Answer:

The correct answer is "The hydrophilic heads will point toward the water, and the hydrophobic tails will point away from the water".

Explanation:

The missing options of this question are:

a. The hydrophobic tails will point toward the water, and the hydrophilic heads will point away from the water.

b. The hydrophilic heads will point toward the water, and the hydrophobic tails will point away from the water.

c. Hydrophilic heads and hydrophobic tails will both point toward the water.

d. The hydrophobic tails and hydrophilic heads will be arranged randomly.

The correct answer is option b. Phospholipids are amphiphilic molecules that have hydrophilic heads and hydrophobic tails. This characteristic makes them the main component of cell's membrane where the hydrophilic tails point outside and inside the cell, and the hydrophobic tails point within the membrane. If phospholipids are found as a sphere in a glass of water, the hydrophilic heads will point toward the water, and the hydrophobic tails will point away from the water. This is the most stable structure, therefore, this will be the arrangement of the phospholipids.

Answer:

Answer in explanation

Explanation:

The similarity between binary ionic and binary covalent substances is that they both contain only 2 elements each. This means there are two elements in the configuration of both. That is the similarity between them

Now the first difference I will like to mention is the way in which they are bonded. While ionic substances are formed through the transfer of electrons, covalent substances are formed through the sharing of electrons. This means that an element with an excess number of electrons transfer completely a number of electrons to an element that is deficient in electrons. This can be seen in the case of sodium and chlorine. The electron that is transferred is controlled only by the nucleus of the second electron. In the covalent bonding however, the electrons are shared and the electrons shared are controlled by the nuclei of both elements

Another difference is that while binary ionic compounds might dissolve only in polar solvents such as water, binary covalent compounds might only dissolve in non polar solvents such as benzene.

Answer:

Similarity: they involve the presence of both a cation and an anion.

Differences:

1. Electron giving is done in ionic compounds and electrons sharing is done in covalent compounds.

2. Stronger interactions in ionic compounds while weak interactions in covalent compounds.

Explanation:

Hello,

In this case, one similarity present between ionic and covalent compounds is that both of them involve the presence of both a cation and an anion which are positive and negative respectively; this is in order to allow the contituents to gather by bonding either ionically or covalently.

On the flip side, on the difference is that ionic compounds involve the giving of electrons since usually just the anion attain the octet while the covelent compounds allow electron sharing to allow both the cation and the anion to attain the octet.

Nevertheless, despite the electron sharing and giving fact, ionic compounds have stronger interactions bonding the cation and the anion than those covalent compounds have. Ionic interactions are electrostatic and covalent interactions are attractive which are by far weaker than those electrostatic.

Best regards.

Answer:

ΔT = 1,41°C

Explanation:

For the reaction:

2HCl(aq) + Ba(OH)₂(aq) → BaCl₂(aq) + 2 H₂O(l); ΔH = –118 kJ.

If moles of reaction are:

HCl:

0,0500L×0,20M = 0,01moles

Ba(OH)₂:

0,0500L×0,10M = 0,005moles

The heat produced is:

0,005mol×-118 kJ/mol = -0,59 kJ = -590 J

The temperature increasing is:

Q = -C×m×ΔT

Where Q is heat (-590 J), m is mass of solution (100mL = 100g -density of 1,00g/mL) and ΔT is change in temperature.

Replacing:

-590J = -4,184J/g°C×100g×ΔT

ΔT = 1,41°C

I hope it helps!

Mendeleev organized the periodic table based on atomic mass and chemical properties, deviating from mass order to group chemically similar elements, which allowed him to predict undiscovered elements.

Dmitri Mendeleev did not order the periodic table by equal rows and columns because, during his arrangement of the elements based on their atomic mass, he discovered that placing elements strictly by mass did not result in a table where elements with similar chemical properties were grouped together. Instead, he noticed a pattern of periodicity, where elements showed repeating properties at certain intervals. To maintain this periodicity and to properly organize elements into groups of similar chemical behaviors, he deviated from strict mass order.

For example, he placed iodine after tellurium despite it being lighter, to align it with chemically similar elements. This arrangement also allowed Mendeleev to predict the existence and properties of elements that were undiscovered at the time, based on the gaps and trends in his table. The columns of Mendeleev's periodic table represent groups and the rows represent periods, each row being more massive than the one above it.

Answer:  The quantity of heat produced by the reaction is +26710.656J

Explanation:

Quantity of Heat, Q = mass * specific heat capacity *temperature change

Q = mCpTc, where m= mass, Cp= specific heat capacity, Tc is temperature change

m= 210.0g, Cp=4.184J/(g · oC), Tc= 57.6 - 27.2 = 30.4 oC

Q = 210.0g *4.184J/(g · oC) * 30.4 oC

Q = +26710.656J

Therefore, the quantity of heat produced by the reaction is +26710.656J.

Note: Even though heat is given out by the system and is normally written as a negative value to indicate that heat is lost, the answer is written as a positive decimal number according to instruction.

Answer:

[tex]CaC_2[/tex]

Explanation:

Given that:-

1 calcium ion is at each corner. Also, 1 corner of the unit cell is shared by 8 unit cubes. So, the share of a tom in one unit cell is:- [tex]\frac{1}{8}[/tex]

Also, there are 8 corners in one unit cell.

So, Total number of atoms at corners = [tex]\frac{1}{8}\times 8[/tex] = 1

Number of calcium atoms in the unit cell = 1

Also, given that there are two carbons which are present internally in the unit cell, So,

Number of carbon atoms in the unit cell = 2

Hence, the formula of the calcium carbide is:- [tex]CaC_2[/tex]

Final answer:

The formula for calcium carbide, given the described crystal structure with calcium ions at the corners and center and carbon atoms along edges and internal to the cell, is CaC2.

Explanation:

To determine the formula for calcium carbide given the crystal structure, we must analyze the arrangement of ions in a unit cell. Each corner atom in the cube is shared among eight unit cells, so only 1/8 of each corner atom actually belongs to one specific unit cell. Since there are eight corner atoms, we can calculate that there is effectively one calcium ion from the corners within one unit cell (8 corners × 1/8 each = 1 calcium ion). Additionally, there is one whole calcium ion at the center of the cell. This means there are two calcium ions per unit cell (1 from corners + 1 from center).

For carbon atoms located along the edges, each one is shared by four unit cells, so only 1/4 of each edge atom is within one unit cell. With 8 edge carbons, this amounts to 2 carbon atoms in total (8 edges × 1/4 each = 2 carbon atoms). Plus, the two entirely internal carbon atoms make for a total of four carbon atoms.

Summing up, there are two calcium ions and four carbon atoms in the unit cell, making the formula for calcium carbide CaC2, since the ratio of calcium to carbon in the unit cell is 2:4, which simplifies to 1:2.