Electronegativity is a concept that is useful along with other concepts in Group of answer choices predicting the polarity of a bond formulating a statement of the octet rule determining the charge of a negative ion deciding how many electrons are involved in a bond

D. The name for the set of independent and dependent variables that will be controlled by the scientist.

The statement, that describes the ‘control’ in an experiment is "the name for the set of independent and dependent variables that will be controlled by the scientist."

A control is an element in an experiment that remains intact or unaffected by other variables. An experiment or observation aiming to minimise the influence of variables other than the independent variable is referred to as a scientific control. It serves as a standard or point of reference against which other test findings are measured.

In a scientific experiment, an independent variable is the variable that is modified or manipulated in order to assess the effects on the dependent variable. In a scientific experiment, the dependent variable is the variable that is being tested and measured. The designation given to the set of independent and dependent variables that the scientist will regulate.

Hence the correct option is D.

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Answer:

See explanation

Explanation:

In this question, we have to follow the IUPAC rules. Lets analyze each compound:

a. 1-methylbutane

In this compound we have a chain of 5 carbons, so the correct name is Pentane.

b. 1,1,3-trimethylhexane

In this compound, we longest chain is made of 7 carbons, so, we have to use the name "heptane". Carbon one would be the closet one to the methyl group, so the correct name is  2,4-dimethylheptane.

c. 5-octyne

In this case, carbon 1 would be the closet one to the triplet bond. With this in mind, the correct name is oct-3-yne.

d. 2-ethyl-1-propanol

In this compound, we longest chain is made of 4 carbons, so, we have to use the name "butane". Carbon one would be the carbon with the "OH" group, so the correct name is  2-methylbutan-1-ol.

e. 2.2-dimethyl-3-butanol

In this case, carbon 1 would be the closet one to the "OH". With this in mind, the correct name is 3,3-dimethylbutan-2-ol.

See figure 1

I hope it helps!

Answer:

118.4 g

Explanation:

4 Ga  +  3 S₂ → 2 Ga₂S₃

According to the equation, for every 4 moles of gallium burned, 2 moles of gallium(III) sulfide.

First, convert grams of Ga₂S₃ to moles.  The molar mass is 235.641 g/mol.

(200.0 g)/(235.641 g/mol) = 0.8487 mol

Use the relationship above to convert moles of Ga₂S₃ to moles of Ga.

(0.8487 mol Ga₂S₃) × (4 mol Ga)/(2 mol Ga₂S₃) = 1.697 mol Ga

Convert moles of Ga to grams.  The molar mass is 69.723 g/mol.

(1.697 mol Ga) × (69.723 g/mol) = 118.4 g

Answer:

Explanation:

The half reaction required

Fe⁺³ + 3 e = Fe

This is a balanced equation

No of atom of Fe on both side = 1

Total charge on the left side = + 3 - 3 = 0

Total charge on the right = 0

three electrons will be required to neutralise +3 charge on the single iron ion .

Considering the definition of bond and the different type of bonds, valence is not one of  the types of bonds.

A chemical bond is defined as the force by which the atoms of a compound are held together. These are electromagnetic forces that give rise to different types of chemical bonds.

In other words, a chemical bond is the force that joins atoms to form chemical compounds and confers stability to the resulting compound.

The covalent bond is the chemical bond between atoms where electrons are shared, forming a molecule. Covalent bonds are established between non-metallic elements, such as hydrogen H, oxygen O and chlorine Cl. These elements have many electrons in their outermost level (valence electrons) and have a tendency to gain electrons to acquire the stability of the electronic structure of noble gas. The shared electron pair is common to the two atoms and holds them together.

An ionic bond is produced between metallic and non-metallic atoms, where electrons are completely transferred from one atom to another. During this process, one atom loses electrons and another one gains them, forming ions.

Metallic bonds are a type of chemical bond that occurs only between atoms of the same metallic element. In this way, metals achieve extremely compact, solid and resistant molecular structures, since the atoms that share their valence electrons.

In summary, valence is not one of  the types of bonds. The types of bonds are covalent, ionic and metallic.

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Answer:

5.42

Explanation:

Step 1: Consider the dissociation of NH₄Br

NH₄Br(aq) ⇒ NH₄⁺(aq) + Br⁻(aq)

Br⁻ is the conjugate base of HBr, a strong acid, so it doesn´t react with water. NH₄⁺ is the conjugate acid of NH₃, so it does react with water.

Step 2: Consider the acid reaction of NH₄⁺

NH₄⁺(aq) + H₂O(l) ⇄ NH₃(aq) + H₃O⁺(aq)

Step 3: calculate the acid dissociation constant for NH₄⁺

We will use the following expression.

[tex]K_a \times K_b = K_w\\K_a = \frac{K_w}{K_b} = \frac{1.00 \times 10^{-14} }{1.76 \times 10^{-5}} = 5.68 \times 10^{-10}[/tex]

Step 4: Calculate the concentration of H₃O⁺

We will use the following expression.

[tex][H_3O^{+} ]= \sqrt{K_a \times C_a } = \sqrt{5.68 \times 10^{-10} \times 0.0255 } = 3.81 \times 10^{-6}M[/tex]

Step 5: Calculate the pH

We will use the following expression.

[tex]pH = -log [H_3O^{+} ] = -log (3.81 \times 10^{-6}) = 5.42[/tex]

The pH of 0.0255 M solution should be 5.42.

Since we know that

ka * kb = kw

So,

ka = kw/kb

= 1.00*10^-14 / 1.76*10^-5

= 5.68*10^-10

Now the concentration of H3O should be

= √ka * Ca

= √5.68*10^-10 * 0.0255

= 3.81*10^-6M

Now the pH value should be

= -log(H3O+)

= -log(3.81*10^-6)

= 5.42

hence, The pH of 0.0255 M solution should be 5.42.

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Answer:

1.22 × 10³ g

Explanation:

Step 1: Write the balanced equation

P₄O₁₀ + 6 H₂O ⇒ 4 H₃PO₄

Step 2: Calculate the moles of H₃PO₄ produced by 3.10 moles of P₄O₁₀

The molar ratio of P₄O₁₀ to H₃PO₄ is 1:4. The moles of H₃PO₄ produced are 4/1 × 3.10 mol = 12.4 mol

Step 3: Calculate the mass corresponding to 12.4 moles of H₃PO₄

The molar mass of H₃PO₄ is 97.99 g/mol.

[tex]12.4 mol \times \frac{97.99g}{mol} = 1.22 \times 10^{3} g[/tex]

Answer:

A) One that occurs on its own

Answer:

See explanation.

Explanation:

Hello,

In this case, we can show how the empirical formula is found by following the shown below procedure:

1. Compute the moles of carbon in carbon dioxide as the only source of carbon at the products:

[tex]n_C=0.01962molCO_2*\frac{1molC}{1molCO_2} =0.01962molC[/tex]

2. Compute the moles of hydrogen in water as the only source of hydrogen at the products:

[tex]n_H=0.01961molH_2O*\frac{2molH}{1molH_2O}=0.03922molH[/tex]

3. Compute the mass of oxygen by subtracting the mass of both carbon and hydrogen from the 0.4647-g sample:

[tex]m_O=0.4647g-0.01962molC*\frac{12gC}{1molC}-0.03922molH*\frac{1gH}{1molH} =0.1900gO[/tex]

4. Compute the moles of oxygen by using its molar mass:

[tex]n_O=0.1900gO*\frac{1molO}{16gO}=0.01188molO[/tex]

5. Divide the moles of carbon, hydrogen and oxygen by the moles of oxygen (smallest one) to find the subscripts in the empirical formula:

[tex]C=\frac{0.01962}{0.01188}=1.65\\ \\H=\frac{0.03922}{0.01188} =3.3\\\\O=\frac{0.01188}{0.01188} =1[/tex]

6. Search for the closest whole number (in this case multiply by 2):

[tex]C_3H_6O_2[/tex]

Moreover, the empirical formula suggests this compound could be carboxylic acid since it has two oxygen atoms, nevertheless, this is not true since the molar mass is 222.27 g/mol, therefore, we should compute the molar mass of the empirical formula, that is:

[tex]M=12*3+1*6+16*2=74g/mol[/tex]

Which is about three times in the molecular formula, for that reason, the actual formula is:

[tex]C_9H_{18}O_6[/tex]

It suggest that the compound has a highly oxidizing character due to the presence of oxygen, therefore, we cannot predict the distribution of the functional groups as it could contain, carboxyl, carbonyl, hydroxyl or even peroxi.

Best regards.

Answer:

0.025 M

Explanation:

The following data were obtained from the question:

Initial volume (V1) = 5 mL

Initial concentration (C1) = 0.5 M

Final volume (V2) = 100 mL

Final concentration (C2) =..?

Using the dilution formula, we can obtain the final concentration of the diluted solution as follow:

C1V1 = C2V2

0.5 x 5 = C2 x 100

Divide both side by 100

C2 = (0.5 x 5)/100

C2 = 0.025 M

Therefore, the final concentration of the diluted solution is 0.025 M

The concentration of the final diluted solution is 0.025M

The dilution formula is expressed according to the formula:

[tex]C_1V_1=C_2V_2[/tex]

Given the following parameters

[tex]C_1=0.5M\\V_1=5.00mL\\V_2=100.0mL\\C_2=?[/tex]

Substitute the given parameters into the formula:

[tex]C_1V_1=C_2V_2\\0.5(5)=100C_2\\2.5=100C_2\\C_2=\frac{2.5}{100}\\C_2= 0.025M[/tex]

Hence the concentration of the final diluted solution is 0.025M

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Answer: The mass of 405 ml of cresol is 415 grams

Explanation:

Density is defined as the mass contained per unit volume.

[tex]Density=\frac{mass}{volume}[/tex]

Given : Density of cresol = 1024 g/L

Volume of cresol = 405 ml = 0.405 L   ( 1L=1000ml)

Putting in the values we get:

[tex]1024g/L=\frac{mass}{0.405L}[/tex]

[tex]mass=1024g/L\times 0.405L=415g[/tex]

Thus mass of 405 ml of cresol is 415 grams

Answer:

1) R₃CO , H, H₃C, a carbon free radical

2) high temperature, ultraviolet irradiation

Explanation:

1) Homolysis leads to the formation of free radicals (species having a free electron). Thus, answer is :

R₃CO

H

H₃C

a carbon free radical

2) Homolysis require high temperature, ultraviolet irradiation.

Answer:

[tex]n_{CO_2}=1.93 gCO_2[/tex]

Explanation:

Hello,

In this case, considering the given chemical reaction, we can use the molar mass of octane (114.23 g/mol) and the 2:16 molar ratio with carbon dioxide to compute the emitted moles of CO2 to the atmosphere via the following stoichiometric procedure:

[tex]n_{CO2}=27.6gC_8H_{18}*\frac{1molC_8H_{18}}{114.23gC_8H_{18}} *\frac{16molCO_2}{2molC_8H_{18}} \\\\n_{CO_2}=1.93 gCO_2[/tex]

Which also corresponds to the following mass:

[tex]m_{CO_2}=1.93molCO_2*\frac{44gCO_2}{1molCO_2} \\\\m_{CO_2}=85.0gCO_2[/tex]

Best regards.

Answer:

Q = 1.5 kJ

Explanation:

It is given that,

The specific heat for aluminum is 0.900 J/g°C

Mass of sample, m = 3.8 g

Initial temperature, [tex]T_i=450^{\circ} C[/tex]

Final temperature, [tex]T_f=25^{\circ} C[/tex]

We need to find the heat released. The amount of heat released is given by the formula:

[tex]Q=mc\Delta T\\\\Q=mc(T_f-T_i)\\\\Q=3.8\times 0.9\times (25-450)\\\\Q=1453.5\ J\\\\Q=1.45\ kJ[/tex]

or

[tex]Q=1.5\ kJ[/tex]

So, the correct option is (A) i.e. 1.5 kJ.

Answer:

Here's what I get  

Explanation:

You have an equilibrium reaction between Fe³⁺/ SCN⁻ and FeSCN²⁺.

[tex]\underbrace{\hbox{Fe$^{3+}$}}_{\text{pale yellow-green}} +\underbrace{\hbox{SCN$^{-}$}}_{\text{colourless}} \, \rightleftharpoons \, \underbrace{\hbox{Fe(SCN)$^{2+}$}}_{\text{deep blood red}} \\[/tex]

When you add AgNO₃, the Ag⁺ reacts with the SCN⁻. It forms a colourless precipitate of Ag(SCN).

Ag⁺(aq) + SCN⁻(aq) ⟶ AcSCN(s)

According to Le Châtelier's Principle, when we apply a stress to a system at equilibrium, the system will respond in a way that tends to relieve the stress.

If you add Ag⁺ to the equilibrium solution, it removes the SCN⁻ [as an Ag(SCN) precipitate].

The system responds by trying to replace the missing SCN⁻:

The Fe(SCN)²⁺ dissociates to form SCN⁻, so the position of equilibrium shifts to the left,

You now have more Fe³⁺ and SCN⁻ and less of the highly coloured Fe(SCN)²⁺ at the new equilibrium.

The deep red colour becomes less intense.

When silver nitrate is added to the Fe/SCN equilibrium,  the colourless intense and precipitate forms because it settles at the bottom.

Chemical equilibrium is the condition in the course of a reversible chemical reaction in which no net change in the amounts of reactants and products occurs.

The added silver nitrate, [tex]AgNO_3[/tex] , effectively removes thiocyanate ions, [tex]SCN^{-1}[/tex], from the equilibrium system via a precipitation reaction when the [tex]Ag^{+1}[/tex] combines with [tex]SCN^{-1}[/tex] to produce insoluble silver thiocyanate, AgSCN, which settles to the bottom of the test tube.

Ag⁺(aq) + SCN⁻(aq) ⟶ AcSCN(s)

According to Principle, when we apply stress to a system at equilibrium, the system will respond in a way that tends to relieve the stress.

Adding Ag⁺ to the equilibrium solution, it removes the SCN⁻ [as an Ag(SCN) precipitate].

The system responds by trying to replace the missing SCN⁻:

The Fe(SCN)²⁺ dissociates to form SCN⁻, so the position of equilibrium shifts to the left,

You now have more Fe³⁺ and SCN⁻ and less of the highly coloured Fe(SCN)²⁺ at the new equilibrium.

The deep red colour becomes less intense.

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Answer:

Edge length of the unit cell is 4.07x10⁻¹⁰m

Explanation:

In a face-centered cubic structure, the edge, a, could be obtained using pythagoras theorem knowing the hypotenuse of the unit cell, b, is equal to 4r:

a² + a² = b² = (4r)²

2a² = 16r²

a = √8 r

That means edge lenght is = √8 r

adius

As radius of Silver is 144pm = 144x10⁻¹²m:

a = √8 r

a = √8 ₓ 144x10⁻¹²m

a = 4.07x10⁻¹⁰m

Answer:

Explanation: M(PCL5)= 31 + 5(35.5)

=208.5g/mol

M(H20)= 18g/mol

n(PCL5) = 75.5÷208.5

= 0.362mol

n(HCl)/n(PCL5)= 5/1

n(HCl)= 5×0.362

=1.81mol of HCl

Answer:

Product: propan-1-ol

Explanation:

IIn this case, we have to remember that [tex]LiAlH_4[/tex]  is a reduction agent.  So, this is a reduction reaction. The [tex]LiAlH_4[/tex] has the ability to produce hydride ions [tex]H^-[/tex]. This ion can attack the carbonyl group generating a negative charge in the oxygen. In the next step, the negative charge in the oxygen can attack a water molecule to protonate the molecule and produce propan-1-ol.

See figure 1

I hope it helps!

Answer:

the density if vinegar will also be needed

Explanation:

Because this is an experiment of volumetric analysis

Answer:

See explanation

Explanation:

1H NMR

In the 2-chloro-pentanal we have 4 different types of hydrogens. Therefore, we will have 4 different signals. (See figure 1)

Red hydrogen

For the red hydrogens we have only 1 neighbor. So, if we follow the n+1 rule we can calculate the multiplicity of this hydrogen. In this case a doublet.

Blue hydrogens

In this case, we have 3 neighbors (one in the right, two in the left). Therefore we will have a quartet.

Purple hydrogens

For these hydrogens, we have also will have a quartet, because we have 3 neighbors (one in the right, two in the left).

Green hydrogens

In the green hydrogen,s we have 5 neighbors (2 in the right 3 in the left). Therefore a sextet would be produced.

Orange hydrogens

Finally, in these hydrogens, we have 2 neighbors. Therefore a triplet is expected.

13C NMR

For the 13C NMR, we have again 4 different kinds of carbons. Therefore we will have 4 signals. The most deshielded carbon, in this case, is the red one (see figure 2), so this carbon would be on the left side (around 190). Then the next deshield carbon is the blue one, due to the "Cl" atom placed on this carbon.

I hope it helps!

Answer:

Hope this helps...

Good luck on your assignment...

Answer:

Cooking a pot of soup

Explanation:

id say that because when you freeze ice cream, its already frozen, so no heat is being released. melting ice wouldn't be the answer because, once again, it is already frozen, and no heat is being released.

Answer:

the correct answer is freezing ice cream

Explanation:

i took the test & got this question correct. also, heat energy is released when freezing because there is no heat energy involved.

Answer:

See figure 1

Explanation:

In the structure of nylon 6,6 we have amide groups. In this functional group, We have a nitrogen bond to hydrogen, so in this bond, we will have a dipole, due to the electronegativity difference. Nitrogen has more electronegativity than hydrogen, therefore a positive dipole would be generated in the hydrogen atom. Additionally, in the carbonyl group (C=O) due to the oxygen, we will have also a dipole, in this case, a negative dipole because the oxygen atom has more electronegativity (compare with carbon).

When we put two strings of nylon 6,6 the positive dipole will interact with the negative dipole and vice-versa and we will obtain the "hydrogen bonds".

See figure 1

I hope it helps!

Answer:

Explanation:

C₈H₁₆ + 12O₂ = 8 CO₂ + 8H₂O.

a )

Heat of formation of C₈H₁₆

[tex]\triangle H_f (C_6H_{16})=-174.5 kJ[/tex]

[tex]\triangle H_f (CO_2)=-393.5 kJ[/tex]

[tex]\triangle H_f (O_2)= 0[/tex]

[tex]\triangle H_f (H_2O)=-285.82 kJ[/tex]

[tex]\triangle H_{reaction} =[/tex] 8 x - 393.5 - 8 x 285.82 + 174.5x 1

= - 5260.06 kJ

b ) Energy required = 2.905 x 10¹⁵kJ

moles of C₈H₁₆ require to be burnt

= 2.905 x 10¹⁵ / 5260.06

= 55.23 x 10¹⁰ moles

= 55.23 x 10¹⁰ x mol weight of C₈H₁₆ g

= 55.23 x 10¹⁰ x 112 g

= 6185.5 x 10¹⁰ g

= 6185.5 x 10⁷ kg

c )

No of litres of CO₂ produced at NTP = 8 x 22.4 x 55.23 x 10¹⁰ L

=  9897.22 x 10¹⁰ L

At 1520 mm of Hg pressure and 250°C

volume of CO₂

= 9897.22  x 10¹⁰ x 760 x ( 273 + 250) / ( 1520 x 273 )

= 9480.3 x 10¹⁰ L .

Answer:

Copper (II) chloride.

Explanation:

Hello,

In this case, considering the described reaction which is also given as:

[tex]2Al + 3CuCl_2 \rightarrow 2AlCl_3 + 3Cu[/tex]

For us to identify the limiting reactant we first compute the available moles of aluminium:

[tex]n_{Al}=512gAl*\frac{1molAl}{27gAl}=19.0molAl[/tex]

Next, we compute the consumed moles of aluminium by the 1147 grams of copper (II) chloride by using their 2:3 molar ratio:

[tex]n_{Al}^{consumed}=1147gCuCl_2*\frac{1molCuCl_2}{134.45gCuCl_2}*\frac{2molAl}{3molCuCl_2} =5.69molAl[/tex]

Thereby, we can infer aluminium is in excess since less moles are consumed than available whereas the copper (II) chloride is the limiting reactant.

Best regards.

Answer:

2ErF3 + 3Mg → 2Er + 3MgF2

Explanation:

Erbium metal is a member of the lanthaniod series. It reacts with halogens directly to yield erbium III halides such as erbium III chloride, Erbium III fluoride etc.

Erbium metal (Er) can be prepared by reacting erbium(III) fluoride with magnesium; the products are erbium metal and magnesium fluoride. This is a normal redox process in which the Erbium metal is reduced while the magnesium is oxidized. The balanced reaction equation of this process is; 2ErF3 + 3Mg → 2Er + 3MgF2

Answer:

[tex]C_{base}=0.302M[/tex]

Explanation:

Hello,

In this case, we can evidence that when calcium hydroxide solution reacts with hydrochloric acid solution, the balanced neutralization reaction turns out:

[tex]2HCl(aq)+Ca(OH)_2\rightarrow CaCl_2(aq)+2H_2O(l)[/tex]

Moreover, the concentration of neutralized calcium hydroxide can be computed by using the 2:1 mole ratio between the base and the acid:

[tex]C_{acid}V_{acid}=2*C_{base}V_{base}\\\\C_{base}=\frac{C_{acid}V_{acid}}{2*V_{base}} =\frac{0.225M*26.85mL}{2*10.0mL}\\ \\C_{base}=0.302M[/tex]

Regards.

Answer:

The element potassium forms a cation with the charge +1 . The symbol for this ion is K⁺, and the name is potassium ion. The number of electrons in this ion is 18.

Explanation:

Potassium is a metal. It belongs to the group 1 elements. Metals form cations by losing electrons. Since potassium is a group element, it forms a cation by losing one electron. The charge it has is +1 due to the excess of the protons compared t the electrons by 1.

Potassium has  19 electrons. Potassium io on the other hand has 19-1 = 18 electrons.

Answer:

1a. 0.89 gcm¯³

1b. Yes.

1c. Tetrahydrofuran.

2. 0.54 g/mL

Explanation:

1. Data obtained from the question include:

Volume = 0.988 L = 988 cm³

Mass = 879 g

1a. Determination of the density

Density = mass /volume

Density = 879/ 988

Density = 0.89 gcm¯³

Therefore, the density of the liquid is 0.89 gcm¯³

1b. From the given data, it is possible to determine the identity of the liquid.

1c. The density of the liquid is 0.89 gcm¯³. Comparing the density of the liquid obtained with those given in the table, the liquid is tetrahydrofuran

2. Data obtained from the question include:

Mass of empty cylinder = 5.25 g

Mass of cylinder and sodium thiosulfate = 75.82 g

Volume = 130.63 mL

Next, we shall determine the mass of sodium thiosulfate. This can be obtain as follow:

Mass of empty cylinder = 5.25 g

Mass of cylinder and sodium thiosulfate = 75.82 g

Mass of sodium thiosulfate =.?

Mass of sodium thiosulfate = Mass of cylinder and sodium thiosulfate – Mass of empty cylinder

Mass of sodium thiosulfate = 75.82 – 5.25

Mass of sodium thiosulfate = 70.57 g

Finally, we shall determine the concentration of the sodium thiosulfate as follow:

Mass = 70.57 g

Volume = 130.63 mL

Concentration =?

Concentration = mass /volume

Concentration = 70.57/130.63

Concentration = 0.54 g/mL

The concentration of the solution is 0.54 g/mL

Answer:

Temperature

Explanation:

Kinetic energy of gass molecules is directly propotional to the temperature.