A 25.0 mL sample of a solution of an unknown compound is titrated with a 0.115 M NaOH solution. A buffer region was found around a pH of 3.5. The unknown compound is

Answer:

conductivity increasing order CH₃-CH₂-OH < HF< NaCl

Explanation:

NaCl is the better conductor comparing with remaining two. it is strong electrolyte. dissociation percent always nearly eqaul to 100% but HF is weaker acid than NaCl and dissociation percent <100% . So, the no of ions furnished by HF less than that of NaCl

CH₃-CH₂-OH organic compound . in general it is not treated as an electrolyte and it cannot carry any charge. If it  carries, it is very very less compared to remaining two

Answer:

D . Sulphur

Explanation:

the element with a 3p4 valence configuration, look in period 3 and group XVI, and that is ...

S, sulfur.

Answer:

427°C .

Explanation:

Step 1:

Data obtained from the question. This include the following:

Initial temperature (T1) = 77°C

Initial pressure (P1) = P

Final pressure (P2) = 2P

Final temperature (T2) =?

Step 2:

Conversion of celsius temperature to Kelvin temperature.

This is illustrated below:

T(K) = T (°C) + 273

Initial temperature (T1) = 77°C

Initial temperature (T1) = 77°C+ 273 = 350K

Step 3:

Determination of the new temperature. The new temperature can be obtained as follow:

P1/T1 = P2/T2

P/350 = 2P/T2

Cross multiply

P x T2 = 350 x 2P

Divide both side by P

T2 = (350 x 2P ) / P

T2 = 700K

Step 4:

Conversion of Kelvin temperature to celsius temperature.

This can be obtained as follow:

T(°C) = T(K) – 273

T(K) = 700K

T(°C) = 700 – 273

T(°C) = 427°C

Therefore, the new temperature of the gas is 427°C

Answer:

a. boiling

Explanation:

Answer:

THE FREEZING POINT OF THE AQUEOUS SOLUTION IS - 7.3 °C

Explanation:

To solve this problem, we must know the following variables:

Normal boiling point of water (solvent) = 100 °C

The molar boiling point elevation constant of water  = 1.51 °C /m

Normla freezing point of water ( solvent) = 0 °C

The molar freezing point depression constant = 1.86 °C /m

The boiling point of the aqueous solution = 105.9 °C

Molarity = xM

Change in boiling point = boiling point of solution - boiling point of water

Change in boiling point = 105.9 - 100 °C

= 5.9 °C

From the formula:

Change in boiling point = i * Kb * M

Re- arranging the formula by making M the subject of the equation, we have:

M = change in boiling point / Kb

i = 1

M = 5.9 °C / 1.51 °C/m

M = 3.907 M

Then, we calculate the freezing point:

Change in freezing point = i * Kb * M

= 1 * 1.86 °C/m * 3.907 M

= 7.267 °C

Hence, the freezing point = freezing point of water - change in freezing point

Freezing point = 0 °C - 7.267 °C

Freezing point = - 7.267 °C

Freezing point = -7.3 °C

Answer:

254.23 g/mol

Explanation:

Atomic mass for Osmium tetroxide would be 254.23 g/ml

Answer:254.2276

Explanation:

Answer:

C. Tetrahedral

Explanation:

Tetrahedral would be the correct choice because the central atom has 4 domains (1 bond counts as 1 domain so 4 bonds =4) and no lone pairs which means it has tetra (which translates to four) domains hence tetrahedral.

Tetrahedral is the shape of a molecule that has 4 atoms bonded to a central atom and no lone pairs of electrons. Hence, option C is correct.

An atom consists of a central nucleus that is usually surrounded by one or more electrons.

Tetrahedral would be the correct choice because the central atom has 4 domains (1 bond counts as 1 domain so 4 bonds =4) and no lone pairs which mean it has tetra (which translates to four) domains hence tetrahedral.

Hence, option C is correct.

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Answer:

The number of moles of Cl₂ present at equilibrium is 3.94x10⁻⁴ moles.

Explanation:

The reaction is:

CO(g) + Cl₂(g) ⇄ COCl₂(g)  

The equilibrium constant of the above reaction is:

K = 1.2x10³

To find the moles of Cl₂ present at equilibrium, let's evaluate the reverse reaction:

COCl₂(g) ⇄ CO(g) + Cl₂(g)  

The equilibrium constant for the reverse reaction is:

[tex] K_{r} = \frac{1}{1.2 \cdot 10^{3}} = 8.3 \cdot 10^{-4} [/tex]

Now, we need to calculate the concentration of CO and COCl₂:

[tex] C_{CO} = \frac{\eta_{CO}}{V} = \frac{0.3500 moles}{3.050 L} = 0.115 M [/tex]

[tex] C_{COCl_{2}} = \frac{\eta_{COCl_{2}}}{V} = \frac{0.05500 moles}{3.050 L} = 0.018 M [/tex]

Now, from the reaction we have:

COCl₂(g) ⇄ CO(g) + Cl₂(g)  

0.018 - x       0.115+x   x    

The concentration of Cl₂ is:

[tex] K_{r} = \frac{[CO][Cl_{2}]}{[COCl_{2}]} [/tex]

[tex] 8.3 \cdot 10^{-4} = \frac{(0.115 + x)(x)}{0.018 - x} [/tex]  

[tex] 8.3 \cdot 10^{-4}*(0.018 - x) - (0.115 + x)(x) = 0 [/tex]  

By solving the above equation for x we have:

x = 1.29x10⁻⁴ M = [Cl₂]

Finally, the number of moles of Cl₂ present at equilibrium is:

[tex] \eta_{Cl_{2}} = C_{Cl_{2}}*V = 1.29 \cdot 10^{-4} mol/L*3.050 L = 3.94 \cdot 10^{-4} moles [/tex]

Therefore, the number of moles of Cl₂ present at equilibrium is 3.94x10⁻⁴ moles.

I hope it helps you!

Answer:

H2O

Electron geometry-tetrahedral

Molecular geometry bent

CH2Cl2

Electron geometry- tetrahedral

Molecular geometry-tetrahedral

OPCL3

Electron geometry- tetrahedral

Molecular geometry- tetrahedral

CO3^2-

Electron geometry- trigonal planar

Molecular geometry- trigonal planar

ALCL6^3-

Electron geometry-octahedral

Molecular geometry- octahedral

SO2

Electron geometry-tetrahedral

Molecular geometry-bent

PCL5

Electron geometry-trigonal bipyramidal

Molecular geometry- trigonal bipyramidal

Explanation:

Water contains four electron domains this corresponds to a tetrahedral electron geometry. How ever, there are two lone pairs in the molecule hence it is bent.

CH2Cl2 is shows a tetrahedral molecular geometry and a tetrahedral electron geometry. This can only be observed from the structure of the compound.

OPCL3 is bonded to four groups making it a tetrahedral molecule. There are non lone pairs on phosphorus so the molecule is not bent.

CO3^2- is bonded to three groups which leads to a trigonal planar geometry.

ALCL6^3- contains six bonding groups which arrange themselves at the corners of a regular octahedron at a bond angle of 90°.

SO2 has four electron domains leading to a tetrahedral electron domain geometry according to valence shell electron pair repulsion theory. However, the lone pairs on the central atom in the molecule leads to a bent molecular geometry.

PCL5 has five electron domains without lone pairs of electrons on its central atom. Hence the molecule possess a trigonal bipyramidal geometry.

The electron geometry and molecular geometry of the molecule are as follows:

A. H₂O: The electron geometry is tetrahedral because it has four electron domains (two bonding pairs and two lone pairs). However, due to the presence of two lone pairs, the molecular geometry is bent or V-shaped.

B. CH2Cl₂: The electron geometry is tetrahedral. However, the molecular geometry is trigonal planar because two of the electron domains are occupied by chlorine atoms, resulting in a bent shape.

C. OPCl₃: The electron geometry is tetrahedral. However, the molecular geometry is trigonal pyramidal because one of the electron domains is occupied by a lone pair on phosphorus.

D. CO3⁻²: The electron geometry is trigonal planar because it has three electron domains (three single bonds). The molecular geometry is also trigonal planar.

E. AlCl6⁻³: The electron geometry is octahedral because it has six electron domains. The molecular geometry is also octahedral.

F. SO₂: The electron geometry is trigonal planar because it has three electron domains (two single bonds and one lone pair). The molecular geometry is bent or V-shaped due to the presence of a lone pair on sulfur.

G. PCl₅: The electron geometry is trigonal bipyramidal because it has five electron domains. The molecular geometry is also trigonal bipyramidal.

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Answer:

B. 1.82(10³) seconds (1820 seconds)

Explanation:

Speed of Light: 3.00(10⁸) m/s or 3.00(10⁵) km/s

We know the distance from the Moon to Earth as 5.46(10⁸) km

We simply divide the distance by the speed of light:

[tex]\frac{5.46(10^8)}{3.00(10^5)}[/tex]

We should get 1820 seconds or B. 1.82(10³) as our answer.

Answer:

The calculator add the CO2 released from the use of electricity, released from driving and the CO2 from the waste that we disposed.

Explanation:

The carbon dioxide, CO2 is what the human body does not need, therefore, we breathe it out, hence taking in oxygen(respiration process). The plants need oxygen for the production of their own food.

The carbon calculator estimate the amount of CO2 that each individual releases into the atmosphere through the consideration of several factors such as the kind of food that we eat.

Therefore, if we are to use the carbon calculator to determine the amount of CO2 that each individual releases into the atmosphere we will have:

The amount of CO2 that each individual releases into the atmosphere =( CO2 released from the use of electricity) + (CO2 released from driving) + (the CO2 from the waste that we disposed).

Answer:

[tex]Fe(C_{2}H_{3}O_{2})_{3}\\Fe (OH)_{3}\\\\NH_{4}(C_{2}H_{3}O_{2})\\\\NH_{4}OH[/tex]

Explanation:

[tex]Fe^{3+}(C_{2}H_{3}O_{2})^{-}_{3}--->Fe(C_{2}H_{3}O_{2})_{3}\\Fe^{3+} (OH^{-})_{3}--->Fe (OH)_{3}\\\\NH_{4}^{+}(C_{2}H_{3}O_{2})^{-}--->NH_{4}(C_{2}H_{3}O_{2})\\\\NH_{4}^{+}OH^{-} ---> NH_{4}OH[/tex]

Answer:

The most common position for an double bond in an unsaturated fatty acid is delta 9 (Δ⁹)

Explanation:

Unsaturated fatty acids are carboxylic acids which contains one or more double bonds. The chain length as well as the number of double bonds is written separated by a colon. The positions of the double bonds are specified starting from the carboxyl carbon, numbered as 1, by superscript numbers following a delta (Δ). For example, an 18-carbon fatty acid containing a  single double bond between carbon number 9 and 10 is written as 18:1(Δ⁹).

In most monounsaturated fatty acids, the double bond is between C-9 and C-10 (Δ⁹), and the other double bonds of polyunsaturated fatty acids are generally Δ¹² and Δ¹⁵. This positioning is due to the nature of the biosynthesis of fatty acids. In the mammalian hepatocytes, double bonds are introduced easily into fatty acids at the Δ⁹ position, but cannot introduce additional double bonds between C-10 and the methyl-terminal end. However, plants are able to introduce these additional double bonds at the  Δ¹² and Δ¹⁵ positions.

Answer:

The balanced equation is given below: C2H6O + 3O2 —> 2CO2 + 3H2O

The coefficients are: 1, 3, 2, 3

Explanation:

C2H6O + O2 —> CO2 + H2O

The above equation can be balance as follow:

There are 2 atoms of C on the left side and 1 atom on the right side. It can be balance by putting 2 in front of CO2 as shown below:

C2H6O + O2 —> 2CO2 + H2O

There are 6 atoms of H on the left side and 2 atoms on the right side. It can be balance by putting 3 in front of H2O as shown below:

C2H6O + O2 —> 2CO2 + 3H2O

There are a total of 3 atoms of O on the left side and a total of 7 atoms on the right side. It can be balance by putting 3 in front of O2 as shown below:

C2H6O + 3O2 —> 2CO2 + 3H2O

Now the equation is balanced.

The coefficients are: 1, 3, 2, 3.

Answer:

The balanced equation is given below: C2H6O + 3O2 —> 2CO2 + 3H2O

The coefficients are: 1, 3, 2, 3

Explanation:

C2H6O + O2 —> CO2 + H2O

The above equation can be balance as follow:

There are 2 atoms of C on the left side and 1 atom on the right side. It can be balance by putting 2 in front of CO2 as shown below:

C2H6O + O2 —> 2CO2 + H2O

There are 6 atoms of H on the left side and 2 atoms on the right side. It can be balance by putting 3 in front of H2O as shown below:

C2H6O + O2 —> 2CO2 + 3H2O

There are a total of 3 atoms of O on the left side and a total of 7 atoms on the right side. It can be balance by putting 3 in front of O2 as shown below:

C2H6O + 3O2 —> 2CO2 + 3H2O

Now the equation is balanced.

The coefficients are: 1, 3, 2, 3.

Explanation:

Answer:

Li

Explanation:

The phenomenon of wave particle duality was well established by Louis deBroglie. The wavelength associated with matter waves was related to its mass and velocity as shown below;

λ= h/mv

Where;

λ= wavelength of matter waves

m= mass of the particle

v= velocity of the particle

This implies that if the velocities of all particles are the same, the wavelength of matter waves will now depend on the mass of the particle. Hence; the wavelength of a matter wave associated with a particle is inversely proportional to the magnitude of the particle's linear momentum. The longest wavelength will then be obtained from the smallest mass of matter. Hence lithium which has the smallest mass will exhibit the longest DeBroglie wavelength

The atom that have the longest de Broglie wavelength is ; ( A ) Li

Wave particle duality is a phenomenon by de Broglie. that shows that The wavelength associated with matter waves is related to its mass and velocity .

Wave particle duality is represented as ;  λ = h / mv

λ= wavelength of matter waves

m= mass of the particle

v= velocity of the particle

Given that the elements have the same velocity the atom that would have the longest de Broglie wavelength is Li

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Answer:

C. An electron at this electrode has a higher potential energy than it has at a standard hydrogen electrode.

Explanation:

The standard hydrogen electrode (SHE) is used to measure the electrode potential of substances. The standard hydrogen electrode is arbitrarily assigned an electrode potential of zero. Recall that electrode potentials are always measured as reduction potentials in electrochemical systems.

For an electrode that has a negative electrode potential, electrons at this electrode have a higher potential energy compared to electrons at the standard hydrogen electrode. Electrons flow from this electrode to the hydrogen electrode.

On the other hand, a positive electrode potential implies that an electron at this electrode has a lower potential energy than it has at a standard hydrogen electrode. Hence electrons will flow from the standard hydrogen electrode to this electrode.

Answer:

CuO(s) + H₂(g) --> Cu(s) + H₂O(l)

Explanation:

It is already balanced. You can see that the values of the elements of the reactants are equal to the values of the elements of the products.

Answer:

it's B: light knocks electrons off metal atoms

Answer:

MgSo4.7H2O = Magnesium sulfate

Cs3PO4.H2O = Cesium Phosphate

Hope this helps!

3.97×1023 molecules C2H6          1 mol  C2H6  

------------------------------------------ x ------------------------------------   = 0.66 mol C2H6

                                                    6.022 x 1023 molec. C2H6

Answer:

The reaction is not in equilibrium

Explanation:

For the reaction:

PCl₅ ⇄ PCl₃ + Cl₂

Equilibrium constant, Kp, is defined as:

[tex]Kp = \frac{P_{PCl_3}P_{Cl_2}}{P_{PCl_5}} = 0.497[/tex]

When this ratio is = 0.497, the reaction is in equilibrium. Replacing the pressures of the problem, reaction quotient, Q, is:

[tex]Q =\frac{1.322atm*0.911atm}{0.820atm} = 1.469[/tex]

As Q ≠ Kp, the reaction is not in equilibrium

To reach the equilibrium, the reaction will shift to the left producing more reactant and decreasing amount of products.

Answer:

See explanation

Explanation:

Hydration of alkenes is a common reaction in organic chemistry. Hydration is simply the addition of water to an alkene. This is an acid catalysed reaction as we can see from the mechanism attached.

Recall that our task is to carry out the synthesis of 2-butanol using an alkene starting material in which there will be no rearrangement of the intermediate carbocation. If we start with the compound shown in the image (but-2-ene), the first step is the formation of the secondary carbocation. This is followed by the addition of water. Subsequently, the added water is deprotonated by another water molecule to yield 2-butanol and the acid catalyst. All these steps have been clearly outlined in the image attached.

Answer: 10 moles/kg.

Explanation:

Given, Mass of solute = 24.2 g

Molar mass of solute = 24.2 g/mol

[tex]\text{Moles of solute =}\dfrac{\text{Mass of solute}}{\text{Molar mass of solute}}\\\\=\dfrac{24.2}{24.2}=1[/tex]

Mass of solvent = 100.0g = 0.1 kg  [1 g=0.001 kg]

[tex]\text{Molality}=\dfrac{\text{Moles of solute}}{\text{kilograms of Solvent}}\\\\=\dfrac{1}{0.1}\\\\=10\ moles/kg[/tex]

Hence, the molality of the resulting solution is 10 moles/kg.

Answer:

Acid, Horizontally, Drain off the acid by opening the stopcock

Explanation:

A buret is a calibrated glass appratus used to measure and deliver accurate volume of liquid, usually acids, in acid-base titrations.

Before usually the buret to carry out your titration reaction, it is advised to condition or prepare your buret for use.

To condition the buret, add a small volume of the acid to the buret and rotate the barrel horizontally to ensure that the liquid ( acid) makes contact with the inner surface of the barrel o the buret.

This procedure is done to wash off any previous acid or liquid that the buret had been used for in previous titrations.

Complete this action by opening the stopcock of the buret to drain off the acid and discarding each volume in a designated waste container.

Note that acids could be corrosive and dangerous to the skin and so should be handled with great care

Answer:

Boron and Aluminium

Explanation:

Boron and Aluminium are present in Group 13 of the modern periodic table. Group 13 (IUPAC System) can also be referred to as Group III-A. Logically, Boron and Aluminum can't be placed alongwith elements such as Yttrium as they don't exhibit properties of a transition metal.

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Answer:

The answer is Electronegativity increases up and to the right

Explanation:

When you move from left to right it increases ( in the periodic table )

But when you move down the table electronegativity decreases.

So “ Electronegativity increases up and to the right” describes the trends the best.

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Answer:

490 J.

Explanation:

The following data were obtained from the question:

Mass (m) = 5 Kg

Height (h) = 10 m

Acceleration due to gravity (g) = 9.8 m/s²

Potential energy (P.E) =..?

Potential energy is the energy stored in a body by virtue of its location. Mathematically, it can be expressed as:

P.E = mgh

Where:

m is the mass of the object measured in kilograms (Kg).

g is the acceleration due to gravity and the value is 9.8 m/s².

h is the height to which the object is located measured in metre (m)

P.E is the potential energy measured in joule (J).

With the above formula, we can obtain the potential energy possed by the object as follow:

P.E = mgh

P.E = 5 x 9.8 x 10

P.E = 490 J

The,the potential energy possed by the object is 490 J

The question is incomplete; the complete question is: Classify each molecule by whether its real bond angles are the same as or different than its model (ideal) bond angles. In other words, do the bond angles change when you switch between Real and Model mode at the top of the page? Same (angles do not change) Different (angles change) Answer Bank | H2O | CO2, SO2, XeF2, BF3 CIF3, NH3, CH4, SF4, XeF4, BrF5, PCI5,SF6

Answer:

Compounds whose real bond angle are the same as ideal bond angle;

SF6, BF3, CH4, PCI5

Compounds whose real bond angles differ from ideal bond angles;

H2O, CO2, SO2, XeF2, CIF3, NH3, SF4, XeF4, BrF5

Explanation:

According to the valence shell electron pair repulsion theory (VSEPR), molecules adopt various shapes based on the number of electron pairs on the valence shell of the central atom of the molecule. The electron pairs usually orient themselves as far apart in space as possible leading to various observed bond angles.

The extent of repulsion of lone pairs is greater than that of bond pairs. Hence, the presence of lone pairs on the valence shell of the central atom in the molecule distorts the bond angles of molecules away from the ideal bond angles predicted on the basis of valence shell electron pair repulsion theory.

For instance, methane is a perfect tetrahedron having an ideal bond angle of 109°28'. Both methane and ammonia are based on a tetrahedron, however, the presence of a lone pair of electrons on nitrogen distorts the bond angle of ammonia to about 107°. The distortion of lone pairs in water is even more as the bond angles of water is about 104°.

Answer:

The percent composition of fluorine is 65.67%

Explanation:

Percent Composition is a measure of the amount of mass an element occupies in a compound. It is measured in percentage of mass.

That is, the percentage composition is the percentage by mass of each of the elements present in a compound.

The calculation of the percentage composition of an element is made by:

[tex]percent composition element A=\frac{total mass of element A}{mass of compound} *100[/tex]

In this case, the percent composition of fluorine is:

[tex]percent composition of fluorine=\frac{39.6 g}{60.3 g} *100[/tex]

percent composition of fluorine= 65.67%

The percent composition of fluorine is 65.67%

Answer:

The percent composition of fluorine is 65.67%

Explanation:

Percent Composition is a measure of the amount of mass an element occupies in a compound. It is measured in percentage of mass.

That is, the percentage composition is the percentage by mass of each of the elements present in a compound.

The calculation of the percentage composition of an element is made by:

In this case, the percent composition of fluorine is:

percent composition of fluorine= 65.67%

The percent composition of fluorine is 65.67%

Answer:

1) HCl (Hydrochloric acid reacts with NH3 and forms dense fumes)

2) Methane (It is from the group of alkanes and is a green house gas)

3) Deliquescent substance (It is a solid which when kept in open forms a solution after sometime)

4) Brass (It is a solid-in-solid solution used to make electrical fittings)

5) Aluminium

Question 2:

1)    Al₂O₃ + 2NaOH    ⇒   2NaAlO₂  (Sodium Aluminate) + H₂O

2)   Zn +  H₂SO₄   (dilute)  =>  ZnSO₄  (Zinc Sulphate) + H₂

Answer:

equations

Aluminium oxide and Sodium hydroxide react to form water and sodium aluminate

Zinc reacts with dilute sulphuric acid to form zinc sulphate and hydrogen gas