The pH of a solution prepared by mixing 50.0 mL of 0.125 M KOH and 50.0 mL of 0.125 M HCl is ________.

Answer:

[tex]\Delta _fH_{NH_3}=-66\frac{kJ}{mol}[/tex]

Explanation:

Hello!

In this case, since the study of the bond energy allows us to compute the enthalpies of some reactions, for this combination reaction by which ammonia is yielded, we understand the enthalpy of reaction equals the enthalpy of formation of ammonia, and, in terms of the bonds energy we can write:

[tex]\Delta _fH_{NH_3}=Delta _rH=\Sigma \Delta H(bonds \ broken)-\Sigma \Delta H(bonds \ formed)[/tex]

Whereas the bonds enthalpy of those bonds that get broken cover the N≡N and the three H-H bonds at the reactants side and the enthalpy of those bonds that are formed cover the six N-H bonds at the products; which means we obtain:

[tex]\Delta _fH_{NH_3}=942\frac{kJ}{mol} +3*436\frac{kJ}{mol}-6*386\frac{kJ}{mol}\\\\\Delta _fH_{NH_3}=-66\frac{kJ}{mol}[/tex]

Which differs from the theoretical value that is -46 kJ/mol.

Best regards!

Answer:

Final pressure =P₂ = 15.13 psi

Explanation:

Given data:

Initial volume = 0.250 L

Initial pressure = 14.7 psi

Initial temperature = -80.0°C (-80.0 +273 = 193 K)

Final volume = 0.375 L

Final temperature = 25.0°C (25+273 =298 k)

Final pressure = ?

Solution:

P₁V₁/T₁ = P₂V₂/T₂  

P₁ = Initial pressure

V₁ = Initial volume

T₁ = Initial temperature

P₂ = Final pressure

V₂ = Final volume

T₂ = Final temperature

Now we will put the values in formula.

P₂ = P₁V₁ T₂/ T₁ V₂  

P₂ = 14.7 psi × 0.250 L × 298 K / 193 K × 0.375 L  

P₂ = 1095.15 psi .L. K / 72.375 K.L

P₂ = 15.13 psi

Answer:

46.32 mL

Explanation:

We'll begin by writing the balanced equation for the reaction. This is illustrated below:

2HNO₃ + Ca(OH)₂ —> Ca(NO₃)₂ + 2H₂O

From the balanced equation above,

The following data were obtained:

Mole ratio of the acid, HNO₃ (nA) = 2

Mole ratio of the base, Ca(OH)₂ (nB) = 1

Next, we shall write out the data obtained from the question. This includes:

Molarity of the acid, HNO₃ (Ma) = 0.181 M

Volume of the base, Ca(OH)₂ (Vb) = 25.1 mL

Molarity of the base, Ca(OH)₂ (Mb) = 0.167 M

Volume of the acid, HNO₃ (Va) =?

Finally, we shall determine the volume of the acid, HNO₃ as shown below:

MaVa/ MbVb = nA/nB

0.181 × Va / 0.167 × 25.1 = 2/1

0.181 × Va / 4.1917 = 2

Cross multiply

0.181 × Va = 4.1917 × 2

0.181 × Va = 8.3834

Divide both side by 0.181

Va = 8.3834 / 0.181

Va = 46.32 mL

Therefore, the nitric acid, HNO₃ required for the reaction is 46.32 mL

Answer:

1.B

2.A

3. B

Explanation:

1. A chemical bond is the physical phenomenon of chemical substances being held together by attraction of atoms to each other through sharing

2. so 2 is electrons of one atom are transferred permanently to another atom.meaning the answer is A

3. is When atoms combine by forming covalent bonds, the resulting collection of atoms is called a molecule. We can therefore say that a molecule is the simplest unit of a covalent compound.

A chemical bond is an attraction between two atoms.

A ionic bond is A bond formed when atoms transfer electrons.

The heat evolved with the [tex]\rm B_2H_6[/tex] has been 58.637 kJ.

From the balanced chemical equation, 1 mole of [tex]\rm B_2H_6[/tex] reacts with 2 moles of Chlorine to give 3 moles of boron chloride and 6 moles of HCl,

The chlorine has been required in double the quantity of boron hexahydride.

The moles of Chlorine has been the limiting reactant.

The chlorine that has been responsible for the reaction with [tex]\rm B_2H_6[/tex] will be:

6 Chlorine = 1 [tex]\rm B_2H_6[/tex]

5.65 L Chlorine = [tex]\rm \dfrac{5.65}{6}[/tex]

5.65 L Chlorine = 0.942 L [tex]\rm B_2H_6[/tex].

The moles of [tex]\rm B_2H_6[/tex] can be calculated as:

1 Mole = 22.4 L

Moles of [tex]\rm B_2H_6[/tex] in 0.942 L = 0.042 mol.

The heat evolved for 1 mole [tex]\rm B_2H_6[/tex] has been -1396 kJ.

The heat evolved for 0.042 mol [tex]\rm B_2H_6[/tex] = 0.042 × -1396 kJ.

The heat evolved = 58.637 kJ.

The heat evolved with the [tex]\rm B_2H_6[/tex] has been 58.637 kJ.

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The value of x​ : 2

Semi-normal Hydrochloric acid solution = 0.5 N = 0.5 M

for titration :

M₁V₁n₁=M₂V₂n₂(1=HCl,2=Na₂CO₃)

[tex]\tt 0.5\times 20\times 1=M_2\times V_2\times 2\\\\M_2V_2=5~mlmol=5.10^{-3}mol[/tex]

[tex]\tt MW=\dfrac{mass}{mol}=\dfrac{0.715}{5.10^{-3}}=143~g/mol[/tex]

MW Na₂CO₃.xH₂O=143

MW Na₂CO₃.xH₂O = MW Na₂CO₃+ MW xH₂O = 143

MW Na₂CO₃ = 106 g/mol

MW xH₂O = 18x

Equation :

[tex]\tt 106+18x=143\\\\18x=37\\\\x=\dfrac{37}{18}=2.056\approx 2[/tex]

Answer:

C

Explanation:

I just took the test

Answer:

B

Explanation:

Answer:

F2 and Cl2 are non-polar because both contains same atom and they have same electronegativity.

ClF and NF3 have polar interactions because there is electronegativity difference between atoms.

Explanation:

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.

Electronegativity is defined as the ability of an element to attract the electrons that link it to another element.

The covalent bond between two atoms can be polar or nonpolar.

When two atoms have different electronegativities, the one with the highest electronegativity will attract the electrons towards each other, giving rise to two opposite charges on the bond. That is, this generates that in a polar molecule there is separation between positive and negative charges. The bonds will be all the more polar the greater the difference in electronegativity between the bound atoms.

On the other hand, the non-polar covalent bond occurs between atoms of the same element or between atoms with very little electronegativity difference. It is thus characterized to molecules or bonds that do not exhibit any polarity.

A molecule is a dipole when there is an asymmetric distribution of electrons because the molecule is made up of atoms of different electronegativity. That is, dipole is formed when the molecule is polar.

So, dipole-dipole forces are forces of attraction between polar molecules. These molecules attract when the positive end of one of them is close to the negative of the other.

Given the above, F₂ and Cl₂ are non-polar molecules and ClF and NF₃ are polar molecules. Then ClF and NF₃ have polar interactions (dipole-dipole forces). -Brainly user

Answer:

I thin its B im not sure though

Explanation:

The puppies from the same set of parents have different color noses because the pink-nosed puppy and the black nosed puppy inherited different combinations of the genes for nose color from their parents. Thus, the correct option is B.

A gene is the unit of inheritance which is made up of DNA (deoxyribonucleic acid). Every person receives two copies or alleles of each gene which is inherited from each of the two parent.

Genes are made up of DNA, so each of the chromosome contains many different genes. Genes carry the information which determines the traits or characteristics that are passed on to their offspring or inherited from the parents.

The puppies from the same set of parents have different colored noses because pink-nosed puppy and the black nosed puppy inherited different combinations of the genes for nose color from their parents.

Therefore, the correct option is B.

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Answer:

Explanation:

2Al(s) + 3 I₂(s)   →    2 Al⁺³    +     6 I⁻

Aluminium is oxidised and iodine is reduced .

so cell potential = Ereduction - Eoxidation

Al⁺³ + 3e = Al          -  1.66 V

I₂ + 2 e = 2 I⁻             0.54 V

=  .54 - ( - 1.66 )

= 1.66 + .54

= 2.2  V

The overall standard cell potential for the given cell that employs the overall cell reaction is; E°_cell = 2.20 V

We are given the cell reaction;

2Al (s) + 3I₂ (s) → 2Al⁺³ + 6I⁻

We are given reduction potential as;

Al⁺³(aq) + 3e⁻ → Al(s) ;E°_red = -1.66 V

However, the standard reduction potential for the reverse of the oxidation reaction is;

Al → Al⁺³(aq) + 3e⁻ ;E°_ox = 1.66 V

We are also given;

I₂ + 2e⁻ = 2I⁻ ;E°_red = 0.54 V

To get  overall standard cell potential, we will add the cell potentials to get;

E°_cell = E°_ox + E°_red

E°_cell = 1.66 + 0.54

E°_cell = 2.20 V

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Answer:

2H⁺(aq) + 2OH⁻(aq)  --> 2H2O(l)

Explanation:

2HBr(aq)+Ba(OH)2(aq)⟶2H2O(l)+BaBr2(aq)

We break the compounds into ions. Only compounds in the aqueous form can be turned into ions.

The ionic equation is given as;

2H⁺(aq)  +  2Br⁻(aq)  + Ba²⁺(aq) + 2OH⁻(aq)   --> 2H2O(l)  +  Ba²⁺(aq)  + 2Br⁻(aq)

Upon eliminating the spectator ions; The net equation is given as;

2H⁺(aq) + 2OH⁻(aq)  --> 2H2O(l)

Answer:

Answer : The volume of water and alcohol present in 675 mL of this solution is 405 mL and 270 mL respectively.

Explanation: As we are given that 40.0 % (v/v) alcohol solution. That means, 40.0 mL of alcohol present in 100 mL of solution.

Now we have to calculable the volume of alcohol in 675 mL solution.

As 100 mL of solution contains 40.0 mL of alcohol

So, 675 mL of solution contains alcohol

Thus, the volume of alcohol = 270 mL

Now we have to calculate the volume of water.

The volume of water = Volume of the solution - Volume of alcohol

Volume of water = 675 mL - 270 mL

The volume of water = 405 mL

Thus, the volume of water = 405 mL

Hence, the volume of water and alcohol present in 675 mL of this solution is 405 mL and 270 mL respectively.

The 720mL of an 80-proof brandy which is 40.0% (v/v) ethyl alcohol, contains 288 mL of ethyl alcohol.

The Percent solutions can be expressed in the form of volume/volume percentage, weight/volume percentage, or, weight/weight percentage. The concentration of the solution in percentage is calculated as the fraction of the weight or volume of the solute related to the total weight or volume of the solution.

The solution where concentration requires to be represented in volume percent (v/v%) when the solute is a liquid phase. It is also applicable to the numerator and the denominator in volume units and is called volume/volume percent.

Volume percentage = (Volume of solute/volume of solution) x 100

The given brandy has ethyl alcohol the v/v % is 40 %.

It means the 40 ml of ethyl alcohol is present in the 100ml of brandy

Given the volume of brandy = 720 ml

Volume of ethyl alcohol in 720 ml of brandy = (40/100)×720 = 288 ml

Therefore, 288 ml of ethyl alcohol is present in 720 ml of brandy which is 40.0% (v/v) ethyl alcohol.

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Your question is incomplete, but most probably complete question was,

An 80 proof brandy is 40.0% (v/v) ethyl alcohol. The "proof" is twice the percent concentration of alcohol in the beverage. How many milliliters of alcohol are present in 720 mL of brandy?

Answer:

Explanation:

Heat required to convert ice to ice at 0⁰C

= mass x specific heat x rise in temperature

= 18 x 2.09 x 20

= 752.4 J .

heat required to convert ice at 0⁰C to water at 0⁰C

mass x latent heat of fusion

= 18 x 336

= 6048 J

Heat required to increase the temperature of water to 100⁰C

= 18 x 4.2 x 100

= 7560 J

Total heat required

7560 + 6048 + 752.4

= 14360.4 J

Answer:

Element Symbol # of Atoms

Sodium   Na   2

Cobalt   Co   3

Hydrogen  H  20

Oxygen   O   10

Explanation:

Explanation:

The gamma ray photons make their arduous journey to the surface of the Sun, they are continuously absorbed by the solar plasma and re-emitted to lower frequencies. ... By the time they get to the surface, their frequencies are mostly only within the IR/visible light/UV spectrum. Nov28,2020

Answer:

411.6 g

Explanation:

The equation for the decomposition of potassium chlorate to produce oxygen is given as;

2KClO3 --> 2KCl + 3O2

From the stochiometry of the reaction 2 mole of KClO3 produces 3 mol of O2

At STP,

1 mol = 22.4L

3 mol = x

x = 67.2L

2 mole of KClO3 produces 67.2L of O2

How many moles would produce 113L?

2 = 67.2

x = 113

x = 3.36 moles

Moles can be converted to mass using;

Mass = moles * Molar mass

Mass = 3,36 * 122.5 g/mol

Mass = 411.6 g

Answer : A

Explanation

B- conduction

c - convection

D heat transfer

Answer:

d

Explanation:

Answer:

They have the same number of valence electrons.

Explanation:

As a rule of thumb, elements with the same chemical properties must have the same number of valence electrons. This is why elements in the same group have similar chemical properties.

Answer:

This question is incomplete.

Explanation:

This question is incomplete because of the absence of given mass and volume, however, the steps below will help solve the completed question. The molarity (M) of a solution is the number of moles of solute per liter of solvent. The formula is illustrated below;

Molarity = number of moles (n) / volume (in liter or dm³)

To calculate the number of moles of NaC₂H₃O₂, we say

number of moles (n) =

given or measured mass of NaC₂H₃O₂ ÷ molar mass of NaC₂H₃O₂

The volume of the solvent must be in liter (same as dm³). Thus, to convert mL to liter, we divide by 1000

The unit for Molarity is M (Molar concentration), mol/L or mol/dm³

Answer:

option B is correct

Explanation:

momentum(p)=mv

mass= m=4 kg

velocity=v=1.5 m/s

P=4kg*1.5 m/s=6.0 kg.m/s

so option B is correct

Answer:

Explanation:

In carbon monoxide ,

2.5 g of carbon reacts with 3.33 g of oxygen

In unknown gas X ,

.75 g of carbon reacts with 2 .00 g of oxygen

2.5 g of carbon will react with 6.66 g of oxygen in X gas .

Ratio of oxygen in two compounds , reacting with same mass of carbon

= 3.33 : 6.66

= 1 : 2 , a simple ratio

It follows law of multiple proportions .

First gas is CO or carbon monoxide

X gas is CO₂ or carbon dioxide .

In this gas , ratio of oxygen reacting with same amount of carbon is doubled .

Answer:

V₂ = 918.1 cm³

Explanation:

Given data:

Initial volume = 640 cm³

Initial temperature = 100°C (100+273 = 373 K)

Initial pressure = 1490 mmHg (1490 /760 = 1.96 atm)

Final volume = ?

Final temperature = 273 K

Final pressure = 1 atm

Solution:

Formula:  

P₁V₁/T₁ = P₂V₂/T₂  

P₁ = Initial pressure

V₁ = Initial volume

T₁ = Initial temperature

P₂ = Final pressure

V₂ = Final volume

T₂ = Final temperature

now we will put the values in formula.

V₂ = P₁V₁ T₂/ T₁ P₂  

V₂ = 1.96 atm × 640 cm³ × 273 K / 373 K × 1 atm

V₂ = 342451.2 atm .cm³ . K / 373 K. atm

V₂ = 918.1 cm³

Answer:

what the answer is dream but what

Explanation:

Answer:

heat, electrical, mechanical, nuclear,sound

Explanation:

The power plant is mechanicalised so it produce heat which is in form of electrical and then we start hearing sound

Answer:hi

Explanation:

Answer:

Temperature and Heat

Explanation:

Proportional to the average kinetic energy of the molecules in a substance.