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Answer:

Kindly check the explanation section.

Explanation:

Without mincing words let us dive right into the solution to the question above, taking each compound at a time.

NB: Kindly Check attachment for the Lewis Structure of each of the chemical compounds.

Therefore, the number of valence electrons, electronic shape, molecular shape and whether the molecules are polar(Polarity) is given below for each chemical compound.

(1). Compound: HCN

(a). number of valence electrons = 10.

(b). electronic shape =linear.

(c). molecular shape = linear.

(d). Polarity = Y.

(2). Compound: PH3

(a). number of valence electrons = 8.

(b). electronic shape = Tetrahedral.

(c). molecular shape = Trigonal Pyramidal.

(d). Polarity = Y.

(3). Compound: CHCl3.

(a). number of valence electrons = 26.

(b). electronic shape = tetrahedral.

(c). molecular shape = tetrahedral.

(d). Polarity = Y.

(4). Compound: NH4^+

(a). number of valence electrons = 8

(b). electronic shape = tetrahedral

(c). molecular shape = tetrahedral

(d). Polarity = Y.

(5). Compound: H2CO

(a). number of valence electrons = 12.

(b). electronic shape = Trigonal planar.

(c). molecular shape = Trigonal planar

(d). Polarity = Y.

(6). Compound: SO4^2-

(a). number of valence electrons = 32.

(b). electronic shape = Tetrahedral.

(c). molecular shape = Tetrahedral.

(d). Polarity = N.

(7). Compound: SeF2.

(a). number of valence electrons = 20.

(b). electronic shape = Tetrahedral.

(c). molecular shape = bent.

(d). Polarity = Y.

(8). Compound: CO2.

(a). number of valence electrons = 16.

(b). electronic shape = linear.

(c). molecular shape = linear.

(d). Polarity = N.

(9). Compound: O2

(a). number of valence electrons = 32.

(b). electronic shape = Trigonal planar.

(c). molecular shape = Linear.

(d). Polarity = N.

(10). Compound: ClO4-.

(a). number of valence electrons = 32.

(b). electronic shape = Tetrahedral.

(c). molecular shape = Tetrahedral.

(d). Polarity = N.

(11). Compound: HBr.

(a). number of valence electrons = 8.

(b). electronic shape = Linear.

(c). molecular shape = Linear.

(d). Polarity = Y.

(12). Compound: PF5.

(a). number of valence electrons = 40.

(b). electronic shape = Trigonal Bipyramidal.

(c). molecular shape = Trigonal Bipyramidal.

(d). Polarity = N.

(13). Compound: BeH2.

(a). number of valence electrons = 4.

(b). electronic shape = Linear.

(c). molecular shape = Linear.

(d). Polarity = N.

(14). Compound: PO4^3-.

(a). number of valence electrons = 32.

(b). electronic shape = Tetrahedral.

(c). molecular shape = Tetrahedral.

(d). Polarity = N.

(15). Compound: BH3.

(a). number of valence electrons = 6.

(b). electronic shape = Trigonal planar.

(c). molecular shape = Trigonal planar.

(d). Polarity = N

(16). Compound: Br3-.

(a). number of valence electrons = 32.

(b). electronic shape = Trigonal Bipyramidal.

(c). molecular shape = Linear.

(d). Polarity = N.

Explanation:

Valves

Blood capillaries

Answer:

102.8 mL.

Explanation:

From the question given above, the following data were obtained:

Molarity of stock solution (M1) = 10.7 M

Molarity of diluted solution (M2) = 0.2 M

Volume of diluted solution (V2) = 5.5 L

Volume of stock solution needed (V1) =.?

The volume of the stock solution needed can be obtained by using the following formula:

M1V1 = M2V2

10.7 × V2 = 0.2 × 5.5

10.7 × V2 = 1.1

Divide both side by 10.7

V2 = 1.1 / 10.7

V2 = 0.1028 L

Finally, we shall convert 0.1028 L to millilitres (mL) in order to obtain the desired result. This can be obtained as follow:

1 L = 1000 mL

Therefore,

0.1028 L = 0.1028 L × 1000 mL / 1 L

0.1028 L = 102.8 mL

Therefore, 0.1028 L is equivalent to 102.8 mL.

Thus, 102.8 mL of the stock solution (i.e perchloric acid) is needed.

Answer:

The answer is 7.89

Explanation:

Mass of methane required to increase the temperature of the air in the room by 7.35 °C is 7.95 g

The volume of air in the room is first calculated:

Volume of air in the room = 4.33 m x 3.43 m x 3.03 = 45.00 m³

1 m³ = 1000 L

45.00 m³ = 45.00 m³ * 1000 L/m³

Volume of air in L = 45000 L

Number of moles of air in 45000 L of air is then determined:

1.00 moles of air occupies 22.4 L

number of moles of air in 45000 L = 45000 L * 1 mole / 22.4 L

number of moles of air = 2008.93 moles of air

Energy that is needed to heat the room by 7.35 °C is then calculated:

Quantity of energy needed = Specific heat capacity * number of moles * temperature increase

Specific heat capacity of air = 30.0 J/K/mole

Quantity of energy needed = 30.0 * 2008.93 * 7.35

Quantity of energy needed = 442969.065 J = 443.00 kJ

The amount of methane required to produce that amount of energy is then calculated:

Equation of combustion of methane : CH₄ + 2 O₂  ---> CO₂ + 2 H₂O

Enthalpy of combustion of methane = −890.3 kJ/mole

Number of moles of methane required = 443.00 kJ / 890.8 kJ/mole = 0.497 moles

Mass of 1 mole of methane = 16.0 g

mass of 0.497 moles of methane = 16.0 * 0.497 = 7.95 g

Therefore, mass of methane required to increase the temperature of the air in the room by 7.35 °C is 7.95 g

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Answer:

The answer is

[tex] \huge 7.40 \times {10}^{21} Hz[/tex]

Explanation:

To find the frequency of the wave we use the formula

[tex]f = \frac{E}{h} \\ [/tex]

where

E is the energy

f is the frequency

h is the Planck's constant which is

6.626 × 10-³⁴ Js

From the question

E = 4.90 × 10-¹² J

So we have

[tex]f = \frac{4.90 \times {10}^{ - 12} }{6.626 \times {10}^{ - 34} } \\ [/tex]

We have the final answer as

[tex]7.40 \times {10}^{21} \: \: Hz[/tex]

Hope this helps you

Answer:

b is the correct answer

do not trust answer one

Explanation:

Answer:

рн

Explanation:

From the given choices, pH is the only chemical property that can be measured quantitatively.

A chemical property is one that tells us about what a substance can do as regards to whether or not the substance reacts with other substances.

Examples are flammability, rusting of iron, precipitation, decomposition of water e.t.c

Answer:

It is more difficult to remove electrons from a noble gas than it is to remove electrons from elements in other groups.

Explanation:

Let me restate here that in the noble gases, the outermost shell is filled. Owing to this full shell, noble gases has the outermost eight electrons required  for any specie to attain stability.

It is very difficult to remove an electron from a closed shell. This is why the first ionization energy of noble gases is usually far higher than that of elements from other groups.

Answer:  Since, the given weight of methane is 16 g, hence the water produced by the combustion of 16 g of methane is 36 g.

Explanation: Have a blessed day!

Answer:

Linear molecule with two domains

Explanation:

Explanation:Thermal energy, or heat, is the energy that comes from the movement of atoms and molecules in a substance. Heat increases when these particles move faster. Geothermal energy is the thermal energy in the earth. Motion energy is energy stored in the movement of objects.

I hope this helped!

Answer:

A graph can be very handy in collecting data and storing it in one place. A graph can be a very effective tool in presenting visual information rather swiftly. Hope this helps! I am learning about graphs in my course!

Explanation:

Answer:

graph) a diagram showing the relation between variable quantities, typically of two variables, each measured along one of a pair of axes at right angles.

Explanation:

Graphing is used daily. From stockbrokers to performance evaluation in companies. All use them to boost sales and meet deadlines. Even simple calculations can be assessed better by using a graph.

(let me know if this helps?)

Answer:

A. the rock on the right is foliated

Explanation:

because if you look at the image then you see that the rock is arranged in layers so you can see that it is a foliated rock and also I got it right on my quiz

HOPE IT HELPS!!!

Answer:

It's a representative metal

Explanation: Transitional metals are metals of various chemical elements and have valence electrons—i.e., electrons that can participate in the formation of chemical bonds.

Answer:

The percentage yield of sodium carbonate is 91.47%

Explanation:

we start by writing the reaction equation:

2NaCl + CaCO3 ——-> Na2CO3 + CaCl2

From the reaction we can see that 2 moles of sodium chloride produced 1 mole of sodium carbonate

Let us calculate the actual number of moles of sodium chloride produced from 112 g of it

Mathematically,

number of moles = mass/molar mass

Molar mass of sodium chloride is 23 + 35.5 = 58.5 g/mole

So the number of moles of sodium chloride produced will be 112/58.5 = 1.91 moles

The number of moles of sodium carbonate produced is half of this = 1.91/2 = 0.955

The mass of sodium carbonate produced from 0.955 moles of it will be;

number of moles * molar mass

The molar mass of sodium carbonate is 106 g/mol

So the number of moles is = 0.955 * 106 = 101.23 g

Mathematically;

percentage yield = actual yield/theoretical yield * 100%

Percentage yield = 92.6/101.23 * 100% = 91.47%

Answer:

d

Explanation:

Answer:

first one is already balanced

2.   MgN2+6HCl->3MgCl2+2NH3

Explanation:

To balance the equations, we need to ensure that the same number of each type of atom is present on both sides of the equation. Here's how we can balance the given equations:

Equation 1: PCl₃ + Cl₂ -> PCl₅

In this equation, there are 1 phosphorus (P) atom, 3 chlorine (Cl) atoms, and 5 chlorine (Cl) atoms. To balance the equation, we can put a coefficient of 2 in front of PCl₃ to have 2 phosphorus atoms, and a coefficient of 5 in front of Cl₂ to have 10 chlorine atoms:

2PCl₃ + 5Cl₂ -> PCl₅

Now the equation is balanced with 2 phosphorus atoms and 10 chlorine atoms on both sides.

Equation 2: Mg₃N₂ + HCl -> MgCl₂ + NH₃

In this equation, there are 3 magnesium (Mg) atoms, 2 nitrogen (N) atoms, 2 hydrogen (H) atoms, and 1 chlorine (Cl) atom.

To balance the equation, we can put a coefficient of 3 in front of HCl to have 3 hydrogen atoms, and a coefficient of 2 in front of NH3 to have 2 nitrogen atoms:

Mg₃N₂ + 3HCl -> MgCl₂ + 2NH₃

Now the equation is balanced with 3 magnesium atoms, 2 nitrogen atoms, 6 hydrogen atoms, and 2 chlorine atoms on both sides.

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Answer:

Hydrogen gas (H2) is a molecule, but not a compound because it is made of only one element. Water (H2O) can be called a molecule or a compound because it is made of hydrogen (H) and oxygen (O) atoms. There are two main types of chemical bonds that hold atoms together: covalent and ionic/electrovalent bonds.

Answer:

A catalytic converter changes nitrogen dioxide to nitrogen gas and oxygen gas is a chemical change.

Explanation:

Hello.

In this case, since physical changes do not modify the molecular composition and structure of the material undergoing it whereas the chemical change does, for catalytic converters we should know they promote chemical reaction in which the composition is changed; for instance, for the given example, the following chemical reaction is the evidence:

[tex]2NO_2\rightarrow N_2+O_2[/tex]

As you can see, nitrogen and oxygen are no longer bonded but separated by themselves, therefore, this is a chemical change.

Best regards.

Answer:

A

Explanation:

Slow cooling of magma beneath the surface of earth

To solve this we must be knowing each and every concept related to rock and its formation. Therefore, the correct option is option A among all the given options.

Rock is a naturally occurring mineral aggregate that is cohesive and composed of one or even more minerals. These aggregates often take the shape of recognisable and mappable volumes and are the fundamental building block of the solid Earth.

Mineral crystals as well as the sorts of rocks that serve as their hosts cycle through many forms as geologic materials. Temperature, weight, time, and variations in the climate in the Earth's crust and on its surface all play a role in the process. Slow cooling of magma beneath the surface of Earth is the  statement that best describes the formation of rock.

Therefore, the correct option is option A.

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Answer:

What mass of sodium hydroxide is needed to react completely with 10.0 g of iron( III) chloride? The conversion sequence is: A. B.

Explanation:

make me as brain liest

Answer:

Explanation:

The volume of a substance when given the density and mass can be found by using the formula

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

From the question

mass = 4.62 g

density = 13.5 g/cm³

We have

[tex]volume = \frac{4.62}{13.5} \\ = 0.3422222...[/tex]

We have the final answer as

Hope this helps you

Answer:

266Lr

Thirteen isotopes of lawrencium are currently known; the most stable is 266Lr with a half-life of 11 hours, but the shorter-lived 260Lr (half-life 2.7 minutes) is most commonly used in chemistry because it can be produced on a larger scale.

Explanation:

hopefully that helps you

Answer:

[tex]Ka_1=1.61x10^{-3}[/tex]

[tex]Ka_2=1.01x10^{-8}[/tex]

Explanation:

Hello.

In this case, since the stepwise dissociation of malonic acid which is a diprotic acid that we are going to symbolize by H₂A, is:

[tex]H_2A\rightleftharpoons H^++HA^-;Ka_1\\\\HA^-\rightleftharpoons H^++A^-;Ka_2[/tex]

The first ionization has the following equilibrium expression:

[tex]Ka_1=\frac{[H^+][HA^-]}{[H_2A]}[/tex]

Whereas the concentration of H⁺ equals the concentration of HA⁻ and is computed via the pH:

[tex][H^+]=[HA^-]=10^{-pH}=10^{-1.47}=0.0339M[/tex]

Next, we compute the molarity of the 19.5 g of malonic acid (molar mass = 104.06 g/mol) as shown below:

[tex][H_2A]=\frac{19.5g/(104.06 g/mol)}{0.250L}=0.750M[/tex]

Thus, Ka1 turns out:

[tex]Ka_1=\frac{(0.0339)(0.0339)}{0.750-0.0339}=1.61x10^{-3}[/tex]

Now, for the second ionization, since the 0.300-M sodium hydrogen malonate is the source of HA⁻, and the pH is 4.26, we can compute the concentration of both H⁺ and A⁻² again by considering the pH:

[tex][H^+]=[A^-^2]=10^{-4.26}=5.50x10^{-5}M[/tex]

Therefore Ka2 turns out:

[tex]Ka_2=\frac{[H^+][A^{-2}]}{[HA^-]}=\frac{(5.50x10^{-5})(5.50x10^{-5})}{0.300-(5.50x10^{-5})}\\ \\Ka_2=1.01x10^{-8}[/tex]

Best regards!

Answer:

Both ionic bonds and covalent bonds (coordinate and non-coordinate) are present in crystalline [tex]\rm CuSO_4\cdot 5\, H_2O[/tex].

Explanation:

[tex]\rm CuSO_4\cdot 5\, H_2O[/tex] can be formed by adding water to the anhydrous salt [tex]\rm CuSO_4[/tex].

[tex]\rm CuSO_4[/tex] itself is an ionic compound consisting of [tex]\rm Cu^{2+}[/tex] ions and [tex]\rm {SO_4}^{2-}[/tex] ions. Ionic bonds are present between these ions. However, within each sulfate [tex]\rm {SO_4}^{2-}[/tex] ion, covalent bonds connect the central sulfur atom to each of the oxygen atoms.

Water molecules [tex]\rm H_2O[/tex] are highly polar. Partial negative charges surround the oxygen atom in each water molecule.

When water is added to anhydrous [tex]\rm CuSO_4[/tex], the negatively-charged portion of these [tex]\rm H_2O\![/tex] molecules would be attracted to the positively-charged [tex]\rm Cu^{2+}[/tex] ions in [tex]\rm CuSO_4\![/tex].

Lone pairs on oxygen atoms in [tex]\rm H_2O\!\![/tex] would form coordinate covalent bonds with [tex]\rm Cu^{2+}\![/tex] ions. (These bonds are considered "coordinate" because both electrons in each of these bonds come from the oxygen atom, not the [tex]\rm Cu^{2+}[/tex] ion.) That would produce coordination complexes with one [tex]\rm Cu^{2+}\!\![/tex] ion and five [tex]\rm H_2O\!\!\![/tex] "ligands" each.

Because the [tex]\rm H_2O[/tex] ligands carry no electric charge, each of these complexes would also carry a charge of [tex](+2)[/tex] (same as the charge on one [tex]\rm Cu^{2+}\!\![/tex] ion.) Ionic bonds would be present between the positively-charged coordination complexes and the negatively-charged [tex]\rm {SO_4}^{2-}[/tex] ions.

Summary:

Answer:

See explanation

Explanation:

Number of moles of naphthalene = 0.32g/128.1705 g/mol = 0.0025 moles

Molality = number of moles/ mass of Solvent in kilograms

Molality = 0.0025/0.025 Kg

Morality = 0.1 m

But

∆T= K × i × m

Where ∆T = boiling point elevation

i= number of particles (this is equal to 1 because naphthalene is molecular and not ionic)

m= molality of naphthalene = 0.1 m

K= boiling point elevation constant = 5.12 °C/m

∆T= 5.12 °C/m ×0.1 = 0.512°C

For freezing point depression

∆T= K× i × m

Where ∆T= freezing point depression

i= number of particles (this is equal to 1 because naphthalene is molecular and not ionic)

m= molality of naphthalene = 0.1 m

K= freezing point depression constant = 2.67 °C/m

∆T= 2.67 °C/m ×0.1 = 0.267°C

From Raoult's law;

∆P = XBPA°

Where;

∆P = vapour pressure lowering

XB = mole fraction of solute

PA° = vapour pressure of pure solvent

Number of moles of solvent = mass/molar mass = 25g/ 78 g/mol= 0.3205 moles

Total number of moles = number of moles of solute + number of moles of solvent = 0.0025 moles + 0.3205 moles = 0.323 moles

Mole fraction of solute = 0.0025 moles/0.323 moles = 0.0077

Vapour pressure of benzene = 100 torr

Therefore;

∆P = 0.0077 × 100torr = 0.77 torr

Hence;

∆P = 0.77 torr

Answer:

2-pentene

hope this helps :)

Explanation: