Draw the Lewis structure for H2O. How many lone pairs of electrons are there in the central atom?

Answer:

83 atoms

Explanation:

5*(1 fe + 2 S) + 6(2 C + 4H + 2O) + 2*2(1 Ca + 2 H + 1 P + 4 O) = 15 + 36 + 32 = 83 atoms

Answer:

Option B:

Electron capture is the combination of a core electron with a proton to yield a neutron within the nucleus.

Explanation:

The electron capture is a nuclear process whereby a neutral atom absorbs an electron from its closest shell (which is usually the K shell of the atom).

This capture phenomenon, causes one of the protons within the nucleus of the atom to convert into a neutron because of the merging of the positive and negative charges. Once they merge, a light particle called the electron neutrino is emitted from the nucleus of the atom.

This phenomenon occurs mostly in atoms that have a proton-rich nucleus. This provides the positive charge that pulls the electron from its shell into the nucleus of the atom.

Answer:

Explanation:

According to Bronsted-Lowry acids or base theory ,  the reagent capable of giving hydrogen ion or proton  will be acid and that which accepts hydrogen ion or proton  will be base .

C₉H₇N + HNO₂   ⇄    C₉H₇NH⁺ + NO₂⁻

If K > 1 , reaction is proceeding from left to right .

Hence HNO₂ is giving H⁺ or proton and C₉H₇N is accepting proton to form

C₉H₇NH⁺ .  

Hence HNO₂ is bronsted acid and C₉H₇N is bronsted base .

B )

when K < 1 , reaction above proceeds from right to left . That means

C₉H₇NH⁺ is giving H⁺ so it is a bronsted acid and NO₂⁻ is accepting H⁺ so it is a bronsted base .

Hence ,  NO₂⁻ is a bronsted base and C₉H₇NH⁺ is a bronsted acid .

Answer:

3.13%

Explanation:

Step 1: Given data

Mass of sodium chloride (solute): 3.60 g

Volume of solution: 115 mL

Step 2: Calculate the weight/volume % of the  solute

We will use the following expression.

%w/v = mass of solute / milliliters of solution × 100%

%w/v = 3.60 g / 115 mL × 100%

%w/v = 3.13%

The weight/volume % of the  solute is 3.13%

Answer:

3.13

Explanation:

correct

Answer:

Have only single bonds.

Explanation:

Hello,

In this case, we need to remember that saturation is a state at which a carbon chain contains no insaturations, that is neither double nor triple bonds such case are alkenes and alkynes, but saturations only which are characterized by the presence of single bonds between adjacent carbon atoms. Such is the case of ethane (CH₃-CH₃), propane (CH₃-CH₂-CH₃), butane (CH₃-CH₂-CH₂-CH₃) and so on.

Best regards.

Answer:

a. (lowest bp) CH3CH2CH3 < CH3OCH3 < CH3CH2OH (highest bp

Explanation:

CH3CH2OH is an alkanol. The intermolecular forces present within the molecules include dispersion forces, dipole-dipole attraction as well as hydrogen bonding which is the major intermolecular force of attraction present.

CH3OCH3 is an ether. The intermolecular forces present within the molecules are dispersion forces and dipole-dipole attraction.

CH3CH2CH3 is an alkane. The only intermolecular forces present is dispersion forces.

The order of increasing strength of these intermolecular forces is dispersion forces ,dipole-dipole forces<hydrogen bonding, the alkanol has the highest bioling point, followed by the ether and then the alkane with the lowest boiling point.

The ranking of the compounds in terms of increasing the boiling point is option a.

Ethanol i.e. (CH3-CH2-O-H) has three types of intermolecular interactions i.e. weak van der Waals interaction, dipole-dipole interaction, and strong intermolecular H-bonding interaction.

While on the other hand,  in dimethyl ether (CH3-O-CH3) have two types of interactions - weak van der Waals interaction, and dipole-dipole interaction.

In propane (CH3-CH2-CH3) has only weak van der Waals interaction.

So ethanol needed more energy to overcome this these interactions for the conversion to a liquid state to the gaseous state.

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Answer:

I hope it will work dear,

Explanation:

by simple mathematical rule,

then we know at half life 50% decay occur hence we get

      2.  50% = T 1/2

solving the 2 equations by cross multiplication we will get,

  T 1/2= 7.96 hr

THANKS FOR ASKING QUESTION:

Answer:

[tex]pH=3.97[/tex]

Explanation:

Hello,

In this case, for the calculation of the pH of the given buffer we need to use the Henderson-Hasselbach equation:

[tex]pH=pKa+log(\frac{[base]}{[acid]} )[/tex]

Whereas the pKa for benzoic acid is 4.19, the concentration of the base is 0.15 M (sodium benzoate) and the concentration of the acid is 0.25 M (benzoic acid), therefore, the pH turns out:

[tex]pH=4.19+log(\frac{0.15M}{0.25M} )\\\\pH=3.97[/tex]

Regards.

Answer:

See explanation

Explanation:

In this case, we can start with the half-reactions. If the total reaction is:

[tex]Zn_(_s_)~+~Cu^2^+~_(_a_q_)~->~Cu_(_s_)~+~Zn^2^+_(_a_q_)[/tex]

If we split the reaction we will have:

Half-reaction 1:

[tex]Zn_(_s_)~->~Zn^2^+_(_a_q_)[/tex]

Half-reaction 2:

[tex]Cu^2^+~_(_a_q_)~->~Cu_(_s_)[/tex]

Now we can add the electrons, keeping in mind that we have to obtain zero charge in both sides of each half-reaction:

Half-reaction 1:

[tex]Zn_(_s_)~->~Zn^2^+_(_a_q_)~+~2e^-[/tex]

Half-reaction 2:

[tex]Cu^2^+~_(_a_q_)~+~2e^-~->~Cu_(_s_)[/tex]

With this in mind, we can solve the questions:

Which one loses electrons?

In half-reaction number 1 we have the electrons in the products side, therefore this half-reaction is the one that loses electrons.

Which one gains electrons

In half-reaction number 2 we have the electrons in the reagent side, therefore this half-reaction is the one that gains electrons.

Which one is oxidized?

If half-reaction number 1 loses electrons will be the oxidation reaction.

Which one is reduced?

If half-reaction number 2 gains electrons will be the reduction reaction.

Which species functions as the oxidizing agent in the following reduction-oxidation reaction?

If half-reaction number 2 is the reduction will be a oxidizing agent.

Which one the reducing agent?

If half-reaction number 1 is the oxidation will be a reducing agent.

I hope it helps!

Answer:

c) CH₃Cl

Explanation:

Due the relative abundance of chlorine and bromine. It is possible to determine which of the halogens is present in a mass spectrum of a organic compound:

The Cl-35, Cl-37 have a relative abundance of 75/25; Br-79 and Br-81 of 50/50.

For that reason, if a compound has a M/M+2 ratio of 75:25 you can be sure the compound has 1 Cl in its structure. Thus, the only possible structure is:

Answer:

14.0 g

Explanation:

Step 1: Given data

Volume of solution (%w/v): 255 mL

Weight/volume % of glucose (solute): 5.50% (m/v)

Step 2: Calculate the mass of glucose

We can calculate the mass of glucose using the following expression.

%w/v = mass of glucose / milliters of solution × 100%

mass of glucose = %w/v × milliters of solution / 100%

mass of glucose = 5.50% (m/v) × 255 mL / 100%

mass of glucose = 14.0 g

Answer:

It shouldn't, but it might there is a chance. Liquid doesn't really weigh that much but it still can add slight weight.

Explanation:

The chemical could maybe make the balancer move a bit. But not a lot.

Answer:

Bohr's Atomic model

Explanation:

The limitations of Bohr’s model are Bohr’s model of an atom that could not explain the line spectra of atoms containing more than one electron called multi-electron atoms.

Answer:

Benzene must be kept away from flames.

Explanation:

Edguenuity 2020

The most accurate statement about Benzene is :  Keep Benzene away from flames.

Although your question is incomplete a general answer is provided based on the MSDS provided in the question

Benzene is a colorless gas that exhibits a high level of flammability, it also has a sweet odor just like gasoline, it is a cancer-causing agent when humans are exposed to it for too long. based on its flammability it is advisable to keep flammable materials and flammable sources ( flames ) away from Benzene. and to also reduce the rate of human exposure to benzene as well.

Therefore we can conclude that based on the MSDS provided in the question the most accurate statement about benzene is Benzene should be kept away from flames.

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Answer:

I would suggest wearing safety glasses as it minimizes the chance of harmful chemicals entering the eyes

Explanation:

Answer:

139/56 Ba

Explanation:

In writing nuclear equations, there must be a balance of the mass and charge on both sides of the reaction equation. That is, the sum of masses on the lefthand side of the nuclear reaction equation must equal the sum of masses on the righthand side of the nuclear reaction equation. Similarly, the charges on the lefthand side of the nuclear reaction equation must equal the sum of the charges on the right hand side of the nuclear reaction equation.

Hence, the isotope of barium formed in the equation mentioned in the question is 139/56 Ba.

Answer:

There will not be any ejection of photoelectrons

Explanation:

Energy of the photon= hc/λ

Where;

h= Plank's constant

c= speed of light

λ= wavelength of the incident photon

E= 6.6×10^-34 × 3 ×10^8/488 × 10^-9

E= 4.1 ×10^-19 J

Work function of the metal (Wo)= 2.9 eV × 1.6 × 10^-19 = 4.64 × 10^-19 J

There can only be ejected photoelectrons when E>Wo but in this case, E<Wo hence there will not be any ejection of photoelectrons.

Answer:

i can't understand the question

Answer:

Explanation:

as we know that

1g =1000mg

so

10g=10*1000

10g=10000

Answer:

C. Zero

Explanation:

A concentration cell is defined as a type of galvanic cell which has two equivalent half-cells of the same constituent in the electrodes but different concentration in the electrolytes.

For a concentration cell, the standard cell potential is always Zero and the cell potential is usually measured with the use of the Nernst equation.

Answer:

a. Tadpoles possess the tendency to grow more rapidly close to the cooling water released from the power plant as the temperature is greater in these waters, permitting them to acquire more nutrients. Thus, in the given case, the factor is the temperature of the system.  

b. In the given case, the factor is the catalyst, and in the given case enzymes are the biological catalyst. An enzyme increases the rate of the reaction as they lower the activation energy.  

c. In the given case, the factor is the enzyme, as the blood comprises an enzyme, peroxidase, which catalyzes the decomposition of hydrogen peroxide.  

Answer: C. Cold air is more dense than hot air.

Explanation: Took the test on edmentum

They use something called Mullerian mimic so they will be protected from predators  

Explanation:

Answer:

F.    [tex]\mathsf{\Delta G^0 \simeq -29.4 \ kJ}[/tex]

Explanation:

GIven that:

The chemical equation for the reaction is:

[tex]\mathtt{Fe_2O_{3(s)} + 3CO_{(g)} \to 2Fe _{(s)} + 3CO_{2(g)}}[/tex]

The value of the ΔG° (kJ/mol) at 25 °C

[tex]\Delta G^0 = \begin {pmatrix} 2( \Delta G_f^0 \ Fe_{(s)} )+ 3 ( \Delta G_f^0 \ CO_{2(g)} ) - 1 ( \Delta G_f^0 \ Fe_2CO_3_{(s)} + 3 ( ( \Delta G_f^0 \ CO _{(g)} ) \end {pmatrix}[/tex]

where;

[tex]\Delta G_f^0 \ Fe_{(s)} = 0[/tex]

[tex]\Delta G_f^0 \ CO_{2(g)} = -394.359 \ kJ/mole[/tex]

[tex]\Delta G_f^0 \ Fe_2CO_3_{(s)} = -742.2 \ kJ/mole[/tex]

[tex]\Delta G_f^0 \ CO _{(g)}= -137.168\ kJ/mole[/tex]

Replacing the values ; we have

[tex]\Delta G^0 = \begin {pmatrix} 2(0 )+ 3 ( -394.359 ) ) -( 1 (-742.2) + 3 (-137.168 ) \end {pmatrix}[/tex]

[tex]\Delta G^0 = \begin {pmatrix} 0 -1183.077 ) -(-742.2- 411.504 \end {pmatrix}[/tex]

[tex]\Delta G^0 = \begin {pmatrix} -1183.077 +742.2+ 411.504 \end {pmatrix}[/tex]

[tex]\mathtt{\Delta G^0 = -29.373 \ kJ}[/tex]

[tex]\mathsf{\Delta G^0 \simeq -29.4 \ kJ}[/tex]

Answer:

[tex]M=0.0256M[/tex]

Explanation:

Hello,

In this case, the undergoing chemical reaction is:

[tex]PbSO_4(aq)+2KCl(aq)\rightarrow PbCl_2(s)+K_2SO_4(aq)[/tex]

In such a way, since all the lead (II) is converted due to the excess of potassium chloride, the moles of lead (II) in the sample are computed from the mass of lead (II) sulfate:

[tex]n_{Pb^{2+}}=12.8gPbSO_4*\frac{1molPbSO_4}{303.3gPbSO_4} *\frac{1molPb^{2+}}{1molPbSO_4} \\\\n_{Pb^{2+}}=0.0422molPb^{2+}[/tex]

Thus, since volume of the solution is 1.65 due to the fact that the addition of the reactants is not enough to significantly modify the reaction's volume, the resulting molar concentration of the lead (II) ions is:

[tex]M=\frac{n_{Pb^{2+}}}{V}=\frac{0.0422molPb^{2+}}{1.65L}\\ \\M=0.0256M[/tex]

Regards.

Answer: 11.2 days

Explanation:

Expression for rate law for first order kinetics is given by:

[tex]t=\frac{2.303}{k}\log\frac{a}{a-x}[/tex]

where,

k = rate constant

t = age of sample

a = let initial amount of the reactant

a - x = amount left after decay process  

a) for completion of half life:

Half life is the amount of time taken by a radioactive material to decay to half of its original value.

[tex]t_{\frac{1}{2}}=\frac{0.693}{k}[/tex]

[tex]k=\frac{0.693}{5.6days}=0.124days^{-1}[/tex]

b) for completion of 75% of reaction

[tex]t=\frac{2.303}{0.124}\log\frac{100}{100-75}[/tex]

[tex]t=\frac{2.303}{0.124}\log\frac{100}{25}[/tex]

[tex]t=11.2days[/tex]

The time for which she has to perform the experiment is 11.2 days

Answer:

A - chemical changes

B - Physical changes

C - Chemical changes

D - Chemical changes

Explanation:

First and foremost, a chemical change is an irreversible change in the chemical properties of a substance leading to the formation of a new substance or substances while a physical change is a reversible change to the properties of a substance.

The burning of a match stick is an irreversible process involving the reaction of the various component of the match head (potassium chlorate, sulfur, glass powder) with that of the side of the box holding the match (phosphorus, binder, glass powder). Hence, it is considered a chemical reaction.

Warming of the metal is a reversible process and hence, a physical reaction. Warming involves a rise in temperature due to the heating. Once the heat source is removed and the metal allowed to stay for a while, its temperature will return back to the original temperature.

Water condensation and deposition of soot on the metal can be considered a chemical reaction. A reaction that leads to the formation of, at least, one new product is definitely a chemical reaction.

Answer:

The correct option is H₂

Explanation:

An ideal gas is the gas that obeys the gas laws perfectly. There molecules occupy little/negligible space with no interaction. Since they occupy negligible space, it can be said that the smaller the molecule of a gas, the more it behaves like an ideal gas. There size also accounts for there weak intermolecular force between it's molecules.

From the explanation above, H₂ has the smallest molecule and hence will behave the most like an ideal gas.

The gases that one would expect to behave the most ideally even under extreme conditions is H2.

H2 is simply known as a molecule of hydrogen that has two hydrogen atoms which are bonded to each other by covalent bond.

Due to the fact that the hydrogen atom has a smaller size and lesser electronegativity the hydrogen molecule is thus regarded to be the least polar.

N2 is known to have greater polarizability than hydrogen molecule and thus cannot be the answer.

Note that for a gas to behave ideally, the attractive and repulsive intermolecular forces need to be negligible. When looking at the three molecules

H2,N2,CO, the molecule which is most polar will behave least ideally.

Therefore, hydrogen molecule will have the least intermolecular forces and will be most ideal.

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