Please help me answer this question

Answer:

C. 43 kJ

Explanation:

Bond energy (bond enthalpy (H) or bond strength) is the amount of energy required to break a bond. The bond energy is used to determine the strength of a chemical bond.

The bond energy is the difference between the energy of the reactants and the energy of the products. The bond energy is given by:

[tex]\Delta H=\Sigma Bond\ energy\ reactants-\Sigma Bond\ energy\ products\\\\Where \ \Delta H=bond\ energy\ or\ energy\ released\\\\Given\ that\ \Delta H=25\ kJ,\Sigma Bond\ energy\ reactants=68\ kJ, Hence:\\\\\Delta H=\Sigma Bond\ energy\ reactants-\Sigma Bond\ energy\ products\\\\Substituting:\\\\25\ kJ=68\ kJ- \Sigma Bond\ energy\ products\\\\ \Sigma Bond\ energy\ products=68\ kJ-25\ kJ\\\\ \Sigma Bond\ energy\ products=43\ kJ\\[/tex]

Answer: is simply C.

Answer:

d. selenium (Se) I’m a non metal

Explanation:

What we know about the element in view is that it has:

              4 orbitals

              6 valence electrons

The orbitals are the energy levels in the element.

Valence electrons are the outermost shell electrons.

The orbitals tells us the periods in which an element belongs. Since we have 4 orbitals, this suggests that our element belongs to the 4th period.

The number of valence electrons tells us the group in which the element could be found. Since we have 6 valence electrons, the group number is 6.

Therefore, the element is period 4 and group 6 is selenium. Selenium is a non-metal.

Answer:

The frequency of the light is 6.62 * 10¹⁴ Hz

Explanation:

The frequency of a wave is defined as the number of complete oscillations made by the wave per second. Its unit is Hertz. The frequency of light as well as the velocity of the light and wavelength of the light are all related.

The velocity of light is the distance the light wave travels per second.

Wavelength is defined as the distance between successive crests and troughs of the wave. It is inversely related to the frequency of the wave.

The velocity of light, c is related to frequency, f, and wavelength, λ, by the formula, c = λf

where the velocity of light, c is a constant = 3 * 10⁸ m/s

λ is wavelength of light = 453 nm = 4.53 * 10⁻⁷ m

Frequency, f = ?

Making f subject of formula in the equation above, f = c/λ

f = 3 * 10⁸ m/s / 4.53 * 10⁻⁷ m

f = 6.62 * 10¹⁴ Hz

Therefore, the frequency of the light is 6.62 * 10¹⁴ Hz

Answer:

0.20

Explanation:

Step 1: Write the balanced equation

2 SO₂(g) + O₂(g) ⇄ 2 SO₃(g)

Step 2: Make an ICE chart

        2 SO₂(g) + O₂(g) ⇄ 2 SO₃(g)

I            3.9         3.2              0

C          -2x          -x             +2x

E        3.9-2x     3.2-x            2x

Step 3: Find the value of x

The partial pressure at equilbrium of SO₃ is 1.6 atm. Then,

2x = 1.6 atm

x = 0.80 atm

Step 4: Calculate the partial pressures at equilibrium

pSO₂ = 3.9-2(0.80) = 2.3 atm

pO₂ = 3.2-0.80 = 2.4 atm

pSO₃ = 1.6 atm

Step 5: Calculate the pressure equilibrium constant

Kp = pSO₃² / pSO₂² × pO₂

Kp = 1.6² / 2.3² × 2.4

Kp = 0.20

Answer:

See explanation

Explanation:

It is clear that certain substituted benzene compounds reacts faster than benzene during electrophillic substitution reactions. This owes to the activation of the benzene ring towards electrophillic substitution by resonance.

The -OCH3 group is ortho- para directing hence it directs an incoming electrophile (such as during bromination) to the ortho or para position as shown in the image attached. This occurs due to resonance (mesomeric) effect as shown in the image attached to this answer.

Image credit: pinterest

Answer:

5.0 × 10²⁴ molecules

Explanation:

Step 1: Write the balanced double displacement reaction

2 NaOH + CuSO₄ ⇒ Na₂SO₄ + Cu(OH)₂

Step 2: Calculate the moles corresponding to 5.0 × 10²⁴ molecules of Na₂SO₄

We will use Avogadro's number: there are 6.02 × 10²³ molecules in 1 mole of molecules.

5.0 × 10²⁴ molecule × 1 mol/6.02 × 10²³ molecule = 8.3 mol

Step 3: Calculate the moles of CuSO₄ required to produce 8.3 moles of Na₂SO₄

The molar ratio of CuSO₄ to Na₂SO₄ is 1:1. The moles of CuSO₄ required are 1/1 × 8.3 mol = 8.3 mol.

Step 4: Calculate the molecules corresponding to 8.3 moles of CuSO₄

We will use Avogadro's number.

8.3 mol × 6.02 × 10²³ molecule/1 mol = 5.0 × 10²⁴ molecule

Answer:

The balanced equation of the reaction is given as follows:

M₂CO₃ + 2HCl ---> 2MCl + H₂O + CO₂

The mole ratio of the metallic carbonate to carbon (iv) oxide is 1:1

The metal is Lithium

Explanation:

The balanced equation of the reaction is given below:

M₂CO₃ + 2HCl ---> 2MCl + H₂O + CO₂

From the equation of reaction, 1 ,mole of the metal carbonate reacts with 2 moles of excess HCl to produce 2 moles of the metallic salt, 1 mole of water and 1 mole of CO₂.

The mole ratio of the metallic carbonate to carbon (iv) oxide is 1:1

Molar mass of CO₂ = 44 g/mol

Number of moles of CO₂ in 1.206 g of CO₂ = 1.206 g / 44 g/mol = 0.0274 moles

Therefore, 2.002 g of M₂CO₃ = 0.0274 moles since all the metallic carbonate was reacted with excess HCl

mass of 1 mole of M₂CO₃ = 2.002/0.0274 = 73.06 g

M₂CO₃ =73.06

2 * M + 12 + 3 *16 = 73.06

2M = 73.06 - 60

M = 13.06/2

M = 6.53 g

Since, the metal belongs to group 1, the metal is most likely Lithium as the molar mass of M is closest to Lithium.

The balanced equation of the reaction is defined as the number of atoms present equally in the reactant and products.

[tex]M_2CO_3 + 2HCl ---> 2MCl + H_2O + CO_2[/tex]

The metal "M" in the reaction is Lithium.

The steps for the balanced reaction is as follows:-

After doing all the steps in the reactions the balanced equation of the reaction is given below:

[tex]Li_2CO_3 + 2HCl ---> 2liCl + H_2O + CO_2[/tex]

This is the balanced reaction.

For more information, refer to the link:-

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Answer:

d the amount of matter in a closed system is the same at the start of a reaction as at the end of the reaction

Answer:

D

Explanation:

i am doing the test rn and i found the answer in other places

Answer:

1s2 2s2 2p6 3s2 3p6

Explanation:

Phosphorus is a non metal. It gains electrons to form ions. The most likely ion formed is the phosphide, where it gains three extra electrons.

Total number of electrons in Phosphide = 15 + 3 =18

The electronic configuration is given as;

1s2 2s2 2p6 3s2 3p6

Electronic Configuration can be defined as the electron distribution of an atom or molecule in an atomic or molecular orbit. The atomic orbit consists of the s, p and d orbitals.

The Atomic number of Phosphorus is 15.

Thus, the Electronic configuration of Phosphorus is 1s² 2s² 2p6 3s² 3p³.

Read more:

What do u mean by electronic configuration? What are basic requirements while writing electronic configuration of an ele...

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Answer:

7. 6 atoms po

Explanation:

sana makatulong po

The mass of 63 ml sample : 79.38 g

Given

20 ml and 25.2 g of glycerol

Required

The mass of 63 ml sample

Solution

Density is the ratio of mass per unit volume

Density formula:

[tex]\large{\boxed {\bold {\rho~=~ \frac {m} {V}}}}[/tex]

Density of glycerol :

= m : V

= 25.2 g : 20 ml

= 1.26 g/ml

Mass of 63 ml sample :

= density x volume

= 1.26 g/ml x 63 ml

= 79.38 g

5.

Solid Phase (Ice)

Unlike most other substances, water's solid form (ice) is less dense than its liquid form, as a result of the nature of its hexagonal packing within its crystalline structure. ... However, a block of ice floats in liquid water because ice is less dense than liquid water.

Unlike most other substances, water's solid form (ice) is less dense than its liquid form, as a result of the nature of its hexagonal packing within its crystalline structure. This lattice contains more space than when the molecules are in the liquid state. ... Liquid water is most dense at 4 degrees Celsius.

6.Evaporation is a phase transition from the liquid phase to the gas phase that occurs at temperatures below the boiling point at a given pressure.

Answer:

Gelada baboons plays a significant role.

Explanation:

The role of gelada baboons in their ecosystem is very important because they aerate the soil for plants which is necessary for good plant growth. These gelada baboons also helps in controlling the population of predator in their ecosystem which is very essential for the stability and equilibrium of the ecosystem so gelada baboons has a good effect on both plants and animals in their ecosystem.

Answer: Primary Consumer

Explanation: Gelada Baboons are herbivores, :D

Answer:

(1). The vapor pressure is 91 mmHg at 20°C.

(2). No, benzene will not boil at sea level.

Explanation:

Benzene, C6H6 is an aromatic, liquid compound with with molar mass of 78.11 g/mol and Melting point of 5.5 °C. One of the importance or the uses of benzene is in the making of fibres and plastics.

The vapour pressure of benzene can be gotten from the table showing the vapor pressure of different liquids.

Boiling point can simply be defined as the point or the temperature in which the vapor pressure is the same with the atmospheric pressure.

The atmospheric pressure is 760mmHg, while the vapor pressure at sea level is at the temperature of 15°C which is equal to 71 mmHg( from the table showing the vapor pressure of different liquids).

71 mmHg is not equal to 760 mmHg, thus, at sea level Benzene will not boil.

A benzene is chemical that is color less or light to the eyes and is liquid at the rom temperature. It has a sweaty odor and is highly flammable.  

Thus the vapor pressure is 91 mmHg at 20°C, and No, benzene will not boil at the sea level.

Learn more about the is at room temperature. what is its vapor.

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Answer:

2,7,4,6

Explanation:

atoms at the left side should be equal to that of right for an equation to be balanced. so the answer is the final one

Answer:

.133

Explanation:

Dissolution of solute lowers the vapor pressure of solvent .

Relative lowering by non -volatile solute is equal to mole fraction of solute dissolved .

Vapor pressure of pure water is 2.33 k Pa

Lowering of vapor pressure = 2.33 - 2.02 = .31 k Pa .

relative lowering = .31 / 2.33 = .133

relative lowering will be equal to mole fraction of non volatile solute like NaCl

so mole fraction of NaCl dissolved = .133

Answer:

Explanation:

λ  =  [tex]10^8[/tex]   meters

Explanation:

f : frequency

c :  velocity of light

λ  : wavelength

f  =  c/λ

λ  =  c /f

c  =  2.99  ⋅ [tex]10^8[/tex] m/ s

λ  =  [tex]10^8[/tex] meters

Answer: calcium ion

Explanation:

Answer:

Kc = 105062.5 at 298K

Explanation:

First of all, we state the equilibrium:

3O₂(g) ⇄  2O₃(g)

We know data about equilibrium concentration of oxygen. We suppose 1 mol of oxygen at the begining. During the reaction, x moles have reacted.

As ratio is 2:3, we can determine how many moles of ozone have been produced.

(x . 2)/3

So we have the final concentration of oxygen, so, let's find out x

1 - x = 0.016 moles

x = 0.984 moles

Then, the [O₃] in equilibrium will be (0.984 . 2) /3 = 0.656.

We supose a volume of 1 L, so we have molar concentration to determine Kc. Let's state the expression for it:

Kc = [O₃]² / [O₂]³

Kc = 0.656² / 0.016³ → 105062.5

Answer: A. 2.0 x 10^-50

Explanation: That’s what I got on Edge.

Answer:

The answer to your question is given below

Explanation:

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

Concentration (g/mL) = 0.04 g/mL

Concentration (g/L) =?

We can convert g/mL to g/L by doing the following:

1 g/mL = 1000 g/L

Therefore,

0.04 g/mL = 0.04 g/mL × 1000 g/L / 1 g/mL

0.04 g/mL = 40 g/L

0.04 g/mL is equivalent to 40 g/L.

Thus, the concentration (g/L) is 40 g/L

Answer:

Au

Explanation:

For the density of a face-centered cubic:

[tex]Density = \dfrac{4 \times M_w}{N_A \times a^3}[/tex]

where

[tex]M_w[/tex] = molar mass of the compound

[tex]N_A=[/tex] avogadro's constant

[tex]a^3 =[/tex] the volume of a unit cell

Given that:

Density [tex](\rho)[/tex] = 19.30 g/cm³

a = 0.408 nm

a = [tex]0.408 \times 10^{-9} \times 10^{2} \ cm[/tex]

a = [tex]4.08 \times 10^ {-8} \ cm[/tex]

∴

[tex]19.3 = \dfrac{4 \times M_w}{(6.023 \tmes 10^{23})\times (4.08 \times 10^{-8})^3}[/tex]

[tex]M_w= \dfrac{19.3\times (6.023 \times 10^{23})\times (4.08 \times 10^{-8})^3}{4}[/tex]

[tex]M_w=197.37 \ g/mol[/tex]

Thus, the molar mass of 197.37 g/mol element is Gold (Au).

Answer:

When 150.0g of the solution are evaporated, 7.50g of KCl must be collected

Explanation:

A solution 5% of potassium chloride means that there are 5g of KCl per 100g of solution.

When all the solution is evaporated, the solute KCl will be collected as a solid.

In 150g of solution there are:

150g * (5.00gKCl / 100g solution) = 7.50g of KCl are present in 150g of solution.

That means:

a. W = 0 J

b. W = - 308.028 J

Given

Nitrogen gas expands in volume from 1.6 L to 5.4 L

Required

The work done

Solution

Isothermal :

W = -P . ΔV

Input the value :

a. At a vacuum, P = 0

So W = 0

b. At pressure = 0.8 atm

W = - 0.8 x ( 5.4 - 1.6)

W = -3.04 L.atm ( 1 L.atm = 101.325 J)

W = - 3.04 x 101.325

W = - 308.028 J

Answer:  [tex]\Delta H[/tex] for the reaction is 87935 J

Explanation:

Molarity of a solution is defined as the number of moles of solute dissolved per Liter of the solution.

[tex]Molarity=\frac{moles}{\text {Volume in L}}[/tex]

[tex]moles of HCl[/tex]=[tex]Molarity\times {\text {Volume in L}}=1.35\times 0.01=0.135moles[/tex]

[tex]moles of NaOH[/tex]= [tex]Molarity\times {\text {Volume in L}}=1.76\times 0.01=0.176moles[/tex]

As 1 mole of HCl neutralizes 1 mole of NaOH

0.135 moles of HCl will neutralize = 0.135 mole of NaOH

Thus HCl is the limiting reagent.

[tex]Q=m\times c\times \Delta T=m\times c\times (T_{final}-T_{initial})[/tex]

Q = Heat absorbed by water = ?

m = mass of water = 200 g    (volume of water=200ml, density of wtaer = 1 g/ml)

c = specific heat capacity = [tex]4.18 J/g^0C[/tex]

Initial temperature of water = = 24.6°C

Final temperature of water=  = 38.8 °C

[tex]Q=200\times 4.18\times (38.8-24.6)[/tex]

[tex]Q=11871.2J[/tex]

Thus heat released by 0.135 moles is = -11871.2 J

heat released by 1 mole is =[tex]\frac{-11871.2 J}{0.135}\times 1=-87935J[/tex]

The heat of reaction, ΔH is 87935 J

Equation of reaction between HCl and NaOH is given below:

Molarity = number of mole/volume

Number of moles = molarity * volume

Number of moles of  HCl = 1.35 M * 0.1 L = 0.135 moles

Moles of NaOH = 1.76 M * 0.1 L = 0.176 moles

1 mole of HCl neutralizes 1 mole of NaOH

Calculating the quantity of heat evolved:

where m is mass, c is specific heat capacity, ΔT is temperature change

Heat absorbed by water, Q = mcΔT

mass of water = density * volume

density of water = 1 g/mL

volume of water = 200 mL

mass of water = 1 g/mL * 200 mL

mass of water = 200 g

specific heat capacity of water, c = 4.18 J/g°C

Initial temperature of water = = 24.6°C

Final temperature of water=  = 38.8 °C

ΔT = 38.8 - 24.6 = 13.7°C

Q = 200 g * 4.18 J/g°C * 14.2°c

Q =  11871.2 J

Therefore, heat released by 0.135 moles is = -11871.2 J

Heat released by 1 mole = 11871.2 * 1/0.135

Heat released by 1 mole = 87935 J

Therefore, the heat of reaction, ΔH is 87935 J

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Answer:

Number of moles = 1.3 mol

Explanation:

Given data:

Number of moles of AlN = ?

Mass of AlN = 52.16 g

Solution:

Formula:

Number of moles = mass/molar mass

Molar mass of AlN = 40 g/mol

By putting values,

Number of moles = 52.16 g/ 40 g/mol

Number of moles = 1.3 mol

The question is incomplete, the complete question is;

3CsBr + Al(OH)3 → AlBr3 + 3CsOH

If 25 g of AlBr3  was produced when 125 mL of a CsBr solution was added, what was the molarity of the CsBr solution?

Answer:

2.25 M

Explanation:

Number of moles of AlBr3   produced = 25g/266.69 g/mol = 0.0937 moles of AlBr3  .

Now, from the reaction equation;

3 moles of CsBr yields 1 mole of AlBr3

Therefore, x  moles of CsBr  will yield 0.0937 moles of AlBr3  

x = 3 * 0.0937 = 0.2811 moles

If 125 mL of a CsBr solution was added

And;

n =CV

where;

n = number of moles

C = concentration of solution

V = volume of solution

C = n/V

C = 0.2811 moles * 1000/125

C= 2.25 M