When a sample of radon decays by alpha emission, the number of daughter isotopes is two.
What is radioactive decay?Radioactive decay refers to the process by which the nucleus of an atom decays spontaneously with the emission of radiation and the formation of one or more new daughter atoms with as smaller nuclei.
The emission of an alpha particle during radioactive decay involves the emission of helium nuclei.
The emission of alpha particles by radon is shown below:
²²²₈₆Ra ---> ²¹⁸₈₄Po + ⁴₂He
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Can you explain why option E is the correct answers?
The reaction as is shown in option E has its enthalpy of reaction not the same as the enthalpy of formation of the product.
What is the enthalpy of formation?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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solid substance A has a melting point of 100C. Liquid substance B has a freezing point of 110C. For each substance, identify it's state of matter and describe the motion of it's particles when the substance is at 115C
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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Which naming rule would apply to CaCO3?
Answer:
A metal + polyatomic anion.
Explanation:
7 A precipitation of iron(III) hydroxide is produced by reacting an aqueous solution of iron(III) chloride with an aqueous solution of sodium hydroxide. Which is the correct balanced chemical equation?
A FeCl₂(aq) + 3NaOH(aq) → Fe(OH)3(s) + 3NaCl(s)
B 3FeCl₂(aq) + 3NaOH(aq) →3Fe(OH)₂(s) + 3NaCl(s)
C 3FeCl3(aq) + NaOH(aq) → Fe(OH)3(s) + 3NaCl(s)
D FeCl₂(aq) + NaOH(aq) → Fe(OH)3(s) + NaCl(s)
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.
What is chemical equation?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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What concentration of CH3NH3Br is necessary to buffer a 0.18 M CH3NH2 solution at pH = 10.00?
(The Kb for CH3NH2 is 4.4 x 10 -4)
The concentration of the specie is obtained as 0.79 M.
What is the concentration?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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calculate the kilojoules needed to heat 175g of copper from 26°c to 184°c
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
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, what is the molarity of the barium hydroxide solution?
The molarity of the barium hydroxide solution is 0.065M.
How to calculate molarity?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;
Ca = initial concentrationCb = final concentrationVa = initial volumeVb = final volumeAccording 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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Write out expanded and condensed structural formulas for methane, CH4; ethane C2H6; propane, C3H6; pentane, C5H12; hexane, C6H14
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
What is meant by the structural formula of an organic compound?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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Predict the products of the following reaction:
HCN + RbOH
Answer:
Rubidium Cyanide and Water
Explanation:
Acetone has a density of 0.7857 g/cm3. What would be the volume in mL of acetone if the mass was 0.3201lbs?
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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18- Separate the following mixtures by using sep-
aration methods, and indicate the minimum amount
of steps necessary for separation.
a. Chalk dust + table salt
b. Iron powder + water + wood
c. Alcohol + water + pepper
Explanation:
A mixture of a solid and a liquid
The small clay particles become suspended in the water. This kind of mixture is called a suspension. Suspensions are opaque; that means they are cloudy and we cannot see through them very well. The sugar dissolves in the water and the mixture is called a solution. Solutions are clear; that means we can see through them.
A mixture of a liquid and a liquid
Milk is not a single substance, but actually a mixture of two liquids! The one liquid component in milk is water, and the other is fatty oil. The reason milk is opaque is that tiny droplets of the oil is suspended in the water. When some liquids are suspended in liquid, we call the mixture an emulsion. Like suspensions, emulsions tend to be opaque.A mixture of vinegar and water is clear, and that is a clue that the mixture is a solution.
Solutions are special kinds of mixtures in which the particles are so well mixed that they are not separated from each other. We cannot make out separate substances.
A mixture of a gas and a gas
We learnt in that Materials that the particles of gases are far apart. This means that gases can mix very easily, because it is easy for their particles to move in amongst each other. The air we breathe is not a single gas but actually a mixture of gases
Why add ammonia to test solution in a penny saved is penny earned lab
Ammonia is added to the test solution in a penny-earned lab to test the behavior of the reaction on a penny.
What is the purpose of the penny lab?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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How many liters of O2 are needed to react completely with 10.0 L of H2s at STP?
2H2S(g) + 3O2(g) --> 2SO2(g) +2H20(g)
Taking into account the reaction stoichiometry,14.9856 L of O₂ are needed to react completely with 10.0 L of H₂S at STP?
Reaction stoichiometryIn first place, the balanced reaction is:
2 H₂S + 3 O₂ → 2 SO₂ + 2 H₂O
By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:
H₂S: 2 molesO₂: 3 molesSO₂: 2 molesH₂O: 2 molesSTP conditionsThe STP conditions refer to the standard temperature and pressure. Pressure values at 1 atmosphere and temperature at 0 ° C are used and are reference values for gases. And in these conditions 1 mole of any gas occupies an approximate volume of 22.4 liters.
Volume of O₂ requiredFirst of all, you know that 10.0 L of H₂S react at STP. You can apply the following rule of three: if by definition of STP conditions 22.4 L of H₂S are occupied by 1 mole, 10 L of H₂S are occupied by how many moles?
moles of H₂S= (10 L× 1 mole)÷ 22.4 L
moles of H₂S= 0.446 moles
To calculate the number of moles of O₂ required, the following rule of three can be applied: If by reaction stoichiometry 2 moles of H₂S react with 3 moles of O₂, 0.446 moles of H₂S react with how many moles of O₂?
moles of O₂= (0.446 moles of H₂S× 3 moles of O₂)÷2 moles of H₂S
moles of O₂= 0.669 moles
Now, you can apply the following rule of three: if by definition of STP conditions 1 mole of O₂ occupies a volume of 22.4 liters, 0.669 moles occupies how much volume?
volume= (0.669 moles× 22.4 L)÷ 1 L
volume= 14.9856 L
Finally, 14.9856 L of O₂ are needed.
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2KClO3⟶2KCl+3O2
Based on this equation, how many grams of KClO3 must be decomposed to produce 5.15 mol KCl ?
mass:
The number of moles of the KClO₃ required to produce 5.15 moles of KCI is equal to 5.15 moles.
What is a mole?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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Please write the trinity for Carbon
The food and agriculture industries' most complete carbon and net-zero route planner.
What uses does carbon serve?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.
What is the origin of carbon?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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If 3.0 grams of Strontium-90 in a rock sample remained in 1989, approximately how many grams of Strontium-90 were present in the original sample in 1933?
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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The mass spectrum of an organic molecule is shown below with m+ peak explain the presence of the second peak labelled m+1
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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At 18 degrees Celsius 34.7 g of carbon dioxide gas creates of 623 mmHg what volume is the gas produced?
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
An ideal gas follows the ideal gas equation.It is also called the equation of state.It is also called the general gas equation.It is derived from the kinetic microscopic theory.It is a generalization form of Charles's law and Boyle's law.This law can be derived from the kinetic theory of gases and relies on the assumptions that (1) the gas consists of a large number of molecules, which are in random motion and obey Newton’s laws of motion.To learn more about ideal gas visit:
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Fill in the blanks to complete the table
The atomic number(Z) is equal to the number of protons to equal to number of electrons.
The number of neutrons is equal to atomic mass minus the atomic number
n=A-Z
For Zn^2+, Z=28, e=28
For iron, Z=25,A=55
The number of neutrons is 55-25=30
The charge is zero
For O^2-, Z=8+2=10, n=p=10
The number of neutrons is 16-10=6
For sulfur, Z=16,A=34
For S2-, Z=16+2=18, A=34
The charge is 2-
The atomic number is the basis of the periodic table.It is equal to the number of protons.The number of neutrons is atomic mass minus atomic number.To learn more about atomic number visit:
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how do you think we can change freedom of movement in molecules.
We can change the freedom of movement in molecules of a substance by the addition or removal of heat.
What are molecules?Molecules are the smallest particles of a substance that are capable of independent existence and that still retain the properties of that substance.
The movement of the molecules of a substance is dependent on the strength of the force of attraction between the molecules of the substance.
The stronger the attractive forces between the molecules of a substance, the less free the molecules of the substance will be to move.
The molecules of a substance can acquire energy to overcome these attractive forces when heat is added to the substance.
Hence, an increase or decrease in the temperature of a substance will change the movement of the molecules of the substance.
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How many valence electrons are shown
Answer:
7
Explanation:
valence electrons are the electrons in the outer shell
what will the kid have brown eyes or blue eyes
the has capital e and lowercase e
the dad has two lowercase e
the picture is the punnett square
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:
Oxygen is inhaled to the lungs, and brought into the blood, which is a . Our bodies exchange the oxygen for carbon dioxide, which is a . The carbon dioxide is forced out of lungs by increasing the pressure of the lungs.
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.
What is meant by respiration?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:
External respirationInternal respirationAerobic respirationAnaerobic respirationSo 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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when a KR-89 captures an electron, what is the particle that is formed?
When a Kr-89 captures an electron, the particle that is formed is bromine with atomic number of 35.
What is radioactivity?Radioactivity is the spontaneous emission of ionizing radiation as a consequence of a nuclear reaction, or directly from the breakdown of an unstable nucleus.
The radiation emitted includes the following;
gamma raysalpha particlesneutronselectronspositronsAn electron is a negatively charged subatomic particle that can be either bound to an atom or free (not bound). It has a charge of -1.
According to this question, when a Kr-89 captures an electron, the particle formed can be deduced as follows:
89/36Kr + 0/-1e = 89/35Br
This suggests that the particle formed when a particle of krypton captures an electron is bromine.
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describe in detail coffee
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.
Help please!!
What is the energy of an electron in the eighth energy level of hydrogen?
The energy of the eight shell of the hydrogen atom is obtained 0.2 eV
What is the energy of the atom?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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Calculate the energy, in kJ, is required to completely melt 20.0 g of ice initially at -45.0 °C.
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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75.0 moles of Copper metal reacts with 70.0 moles of chlorine gas to produce copper (II) chloride.
Which reactant is the excess reactant?
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
Consider the following equilibrium system:
2HI ⇌ H2 + I2
At constant temperature and volume, more I2 is added to the above equilibrium. A new state of equilibrium results from a shift to the:
A) Left with a net decrease in [H2]
B) Left with a net Increase in [H2]
C) Right with a net decrease in [H2]
D) Right with a net increase in [H2]
At constant temperature and volume, more I2 is added to the above equilibrium. A new state of equilibrium results from a shift to the:
Left with a net decrease in [H2].
Hence, Option A is correct .
What do you mean by equilibrium in chemistry?
Chemical equilibrium, can be defined as the reversible chemical reaction in which there is no net change in the amounts of reactants and products. Types of chemical equilibrium are Homogeneous Equilibrium and Heterogeneous Equilibrium
It plays a important role in chemical reaction
It tells us about direction of chemical reaction. It leads in setting up of certain desired products. It helps in calculation of composition of final reactionRate of forward reaction = Rate of backward reaction.
Hence , At constant temperature and volume, more I2 is added to the above equilibrium. A new state of equilibrium results from a shift to the:
Left with a net decrease in [H2].
Hence, Option A is correct .
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Part A
Draw the Lewis structure for H3COCH3
Draw the molecule by placing atoms on the canvas and connecting them with bonds. Include all lone pairs of electrons. Include all hydrogen atoms.
IC
Q
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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