Which letter? Thanks in advance!

Answer:

Calculate the mass of BR -79? Bromine has 2 naturally occurring isotopes (Br-79 and Br-81) and has an atomic mass of 79.904 amu

Explanation:

if i get this wrong srry

If we add water to a concentrated acid, then the solution may boil very violently, splashing concentrated acid. If add acid to water, the solution that forms is very dilute and a small amount of heat is released.

When a strong acid is poured into water, it flows down the flask and mixes much better, so no boiling takes place. The addition of water to acid forms an extremely concentrated solution of acid initially. A large amount of heat is released and the solution may boil very violently, splashing concentrated acid out of the beaker and all this because the reaction is exothermic in nature.

The reason this takes place is due to a large amount of energy liberated in the hydration reaction of concentrated ions. Therefore, we add acid to water dropwise for the dilution with constant stirring and not water to acid directly.

If we add water to acid, then an exothermic reaction occurs and the solution may boil very violently. To form the dilute solution of any strong acid, you should add acid to water and the small amount of heat released is not sufficient to vaporize and spatter it.

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Explanation:

i dont understand dont you already have the equation?

The net ionic equation for the acid-base reaction PH[tex]_3[/tex](aq) + HCl(aq) [tex]\rightarrow[/tex] PH[tex]_4[/tex]Cl(aq) is PH[tex]_3[/tex](aq) + H⁺ (aq) [tex]\rightarrow[/tex] PH[tex]_4[/tex]⁺ .

Chemical reaction equations can be written in a variety of ways. Unbalanced chemical equations, which identify the species involved, balanced chemical equations, which identify the number and type of species, molecular equations, that also express compounds as molecules rather than component ions, and net ionic equations, which only address the species which contribute to a reaction, are some of the most popular.

A chemical equation for just a process known as the net ionic equation only includes the species that are really involved in the reaction.

PH[tex]_3[/tex](aq) + HCl(aq) [tex]\rightarrow[/tex] PH[tex]_4[/tex]Cl(aq)

PH[tex]_3[/tex](aq) + H⁺ (aq)  + Cl⁻ (aq) [tex]\rightarrow[/tex] PH[tex]_4[/tex]⁺ (aq)  + Cl⁻ (aq)

PH[tex]_3[/tex](aq) + H⁺ (aq) [tex]\rightarrow[/tex] PH[tex]_4[/tex]⁺

Therefore,  the net ionic equation for the acid-base reaction is PH[tex]_3[/tex](aq) + H⁺ (aq) [tex]\rightarrow[/tex] PH[tex]_4[/tex]⁺ .

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okay so the  Answer is c

Answer:

An increase on temperature.

Explanation:

Answer: adding a catalyst or increasing temperature

Explanation:

Answer:

your answer should be B.273 K

Explanation:

Answer:

atomic number of 12 is MG

Explanation:

Magnesium

Answer: Therefore, the volume of a 0.155 M potassium hydroxide solution  is 56.0 ml

Explanation:

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

According to the neutralization law,

[tex]n_1M_1V_1=n_2M_2V_2[/tex]

where,

[tex]M_1[/tex] = molarity of [tex]HBr[/tex] solution = 0.338 M

[tex]V_1[/tex] = volume of [tex]HBr[/tex] solution = 25.7 ml

[tex]M_2[/tex] = molarity of [tex]KOH[/tex] solution = 0.155 M

[tex]V_2[/tex] = volume of [tex]KOH[/tex] solution = ?

[tex]n_1[/tex] = valency of [tex]HBr[/tex] = 1

[tex]n_2[/tex] = valency of [tex]KOH[/tex] = 1

[tex]1\times 0.338\times 25.7=1\times 0.155\times V_2[/tex]

[tex]V_2=56.0ml[/tex]

Therefore, the volume of a 0.155 M potassium hydroxide solution  is 56.0 ml

Answer:

1. a

Explanation:

2. c

Answer:

1 is A number two is C

There are total three laws of newtons, first law of newtons, second law of newton and third law of newton. Therefore, when a golf club is subjected to an imbalanced force, its velocity changes, which is according to newton’s second law.

According to Newton's Second Law of Motion, acceleration (gaining speed) occurs when a force acts on a mass (object). Riding a bicycle is a great example of this rule of motion in action. The mass is represented by your bicycle. The force is generated by your leg muscles pulling on the pedals of your bicycle.

The ball remains balanced on the tee due to the balanced forces of gravity downhill and upward. Force equals mass multiplied by acceleration (f=ma). When a golf club is subjected to an imbalanced force, its velocity changes.

Therefore, when a golf club is subjected to an imbalanced force, its velocity changes, which is according to newton’s second law.

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Answer:

Environmental cleanup includes removal of heavy metals and other toxic contaminants from the environment and the process is called remediation.

Answer:

Explanation:

M1V1=M2v2

M1=0.150M

M2=0.150M

V2=120*10^-3

V1=M2V2/M1

V1=0.150*120*10^-3/0.150

V1=0.12

0.12 mL volume of 0.150M 2M Li₂S solution is required to completely react with 120 mL of 0.150M Co(NO₃)₂ MCo(NO₃)₂.

With M1 and M2 representing the molarity of the solutions, expressed as mol/L or M, and V1 and V2 representing their respective volumes, this calculator may be used to calculate a missing number for the dilution equation.

A solution's concentration is determined by multiplying its volume by its molarity (M1V1 = M2V2) On both sides of the equation, the units should stay the same.

Here

M₁V₁=M₂V₂

M₁=0.150M

M₂=0.150M

V₂=120 × 10⁻³

V₁=M₂V₂/M₁

V₁=0.150 × 120 × 10⁻³/0.150

V₁=0.12.

Therefore, 0.12 mL volume of 0.150M 2M Li₂S solution is required to completely react with 120 mL of 0.150M Co(NO₃)₂ MCo(NO₃)₂.

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Answer:

Heat can travel from one place to another in three ways: Conduction, Convection and Radiation. Both conduction and convection require matter to transfer heat. If there is a temperature difference between two systems heat will always find a way to transfer from the higher to lower system.

Explanation:

Answer:

6 atoms

Explanation:

Answer:

Q = 7.7 KJ

Explanation:

The complete question carries the following data:

Specific Heat Capacity of Liquid State = C(l) = 1.45 J/mol.°C

Specific Heat Capacity of Gaseous State = C(g) = 0.65 J/mol.°C

Boiling Temperature = Tb = 88.5°C

Heat of Vaporization = ΔH(vap) = 1.23 KJ/mol

Now, first we calculate the heat required (Q₁) to raise he temperature to boiling point:

Q₁ = n*C(l)*ΔT₁

where,

n = no. of moles = 5.31 mol

ΔT₁ = Temperature difference from 40°C to Tb = 88.5°C - 40°C = 48.5°C

Therefore,

Q₁ = (5.31 mol)(1.45 J/mol.°C)(48.5°C)

Q₁ = 373.4 J = 0.37 KJ

Now, we calculate the heat required (Q₂) to change its phase:

Q₂ = nΔH(vap)

Q₂ = (5.31 mol)(1.23 KJ/mol)

Q₂ = 6.53 KJ

Now, we calculate the heat required (Q₃) to raise he temperature to boiling point:

Q₃ = n*C(g)*ΔT₃

where,

n = no. of moles = 5.31 mol

ΔT₃ = Temperature difference from Tb to 113°C = 113°C - 88.5°C = 24.5°C

Therefore,

Q₃ = (5.31 mol)(0.65 J/mol.°C)(24.5°C)

Q₃ = 84.5 J = 0.08 KJ

So, the total heat required to convert 5.31 mol of this pure substance from a liquid at 40°C to a gas at 113°C is:

Q = Q₁ + Q₂ + Q₃

Q = 0.37 KJ + 6.53 KJ + 0.08 KJ

Q = 7.7 KJ

The total heat required to convert the pure substance from liquid to gas at the given temperature is 814 J.

The given parameters;

The total heat required to convert the pure substance from liquid to gas at the given temperature is calculated as follows;

[tex]Q = nc_l \Delta \theta + nc_g \Delta \theta \\\\ \Delta \theta = (113 - 40) = 73^0 C \\\\Q = (5.31 \ mol \times 1.45 \frac{J}{mol .\ ^0C} \times 73\ ^0C) + (5.31 \ mol \times 0.65 \frac{J}{mol .\ ^0C} \times 73 \ ^0C)\\\\Q = 814 \ J[/tex]

Thus, the total heat required to convert the pure substance from liquid to gas at the given temperature is 814 J.

"Your question is not complete, it seems to be missing the following information;"

How much heat would be required to convert 5.31 mol of a pure substance from a liquid at 40.0°C to a gas at 113.0°C? (molar heat capacity of liquid, C(l) is 1.45 J/mol.⁰C and molar heat capacity of gas, C(g) is 0.65 J/mol.⁰C).

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Answer:

Explanation:

2NaNO₃ = 2NaNO₂ + O₂

NaNO₃    =     NaNO₂   +    1/2 O₂

- 468 kJ           -369 kJ           0  kJ

enthalpy of decomposition reaction

= - 369 - ( - 468 ) kJ

= 99 kJ / mol .      

Answer:

Endothermic

Explanation:

In order to melt the ice cube, heat is required, so the process is endothermic. Endothermic reaction In an endothermic reaction, the products are higher in energy than the reactants. Therefore, the change in enthalpy is positive, and heat is absorbed from the surroundings by the reaction.

Answer:

BeO will have the greatest mass composition of oxygen

Explanation:

To solve this problem, we would find the mass composition of oxygen in each of the given sample.

To find this mass composition, let us derive the molecular mass of the given species;

  K₂O₂ = 2(39) + 2(16) = 110g/mol

  Na₂O = 2(23) + 16 = 62g/mol

   BeO = 9 + 16  = 25g/mol

Now; we know that mass of each sample is 1g;

mass composition of O in K₂O₂ = [tex]\frac{32}{110}[/tex] x  1= 0.29g

mass composition of O in Na₂O = [tex]\frac{16}{62}[/tex] x 1 = 0.26g

mass composition of O in BeO = [tex]\frac{16}{25}[/tex] x 1 = 0.64g

We can see that BeO will have the greatest mass composition of oxygen.

The mass composition of oxygen has been highest in BeO. Thus, option 3 is correct.

The molecular mass has been the mass of each element that has been present in the compound. The molecular mass of given compounds have been:

= 2 (39) + 2 (16)

= 110 g/mol

= 2 (23) + 16

= 62 g/mol

= 9 + 16

= 23 g/mol

The mass composition of oxygen in 1 gram of the following compounds have been:

Mass composition = [tex]\rm \dfrac{Mass\;of\;Oxygen}{Molecular\;mass\;of\;compound}\;\times\;weight\;of\;sample[/tex]

[tex]\rm K_2O_2[/tex] = 0.29 grams

[tex]\rm Na_2O[/tex] = 0.26 grams

BeO = 0.64 grams.

The mass composition of oxygen has been highest in BeO. Thus, option 3 is correct.

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Answer:

X represents London dispersion forces, and Y represents dipole-dipole forces.

Explanation:

Answer:

[tex]312 \ mol \ solute[/tex]

General Formulas and Concepts:

Chemistry

Explanation:

Step 1: Define variables

M = 0.722

L = 431.9

m = x

Step 2: Solve for x

Step 3: Check

Our smallest sig figs is 3. Follow sig figs rules.

[tex]311.832 \ mol \approx 312 \ mol \ solute[/tex]

Answer:

The maximum possible yield strength for a single crystal is 70 MPa.

Explanation:

To find the maximum possible yield strength for a single crystal we need to use the following equation:

[tex]\sigma_{y} = \frac{\tau_{CRSS}}{m_{max}}[/tex]

Where:

[tex]m_{max}[/tex] is the maximum value for Schmid factor

[tex]\tau_{CRSS}[/tex] is the critical resolved shear stress = 35 MPa

[tex] \sigma_{y}[/tex] is the yield strength =?    

The Schmid factor is given by:

[tex]m = cos(\phi)cos(\lambda)[/tex]

And its maximum value is obtained when λ = 45° and Φ = 45°, so:

[tex] m = cos(45)cos(45) = 0.5 [/tex]

Finally, the maximum possible yield strength is:

[tex]\sigma_{y} = \frac{\tau_{CRSS}}{m_{max}} = \frac{35 MPa}{0.5} = 70 MPa[/tex]

Therefore, the maximum possible yield strength for a single crystal is 70 MPa.

I hope it helps you!                                                                                  

Answer:

See explanation

Explanation:

The reaction is shown in the image attached. This reaction occurs by a carbocation (ionic) mechanism.

The lone pair on the nitrogen atom attacks the carbocation leading to the formation of the product as shown in the image attached.

Since the reaction occurs in a 1:1 ratio, two moles of reactants yields two moles of product.

Answer:

If each side of the equation has the same number of atoms of a given element, that element is balanced. If all elements are balanced, the equation is balanced.

Explanation:

Answer:

The answer is Diffusion.

Answer:

Hypertonic

Explanation:

Explanation:

Bohr built on Nicholson's idea by adopting the requirement that the angular momentum can have only certain discrete values related to Planck's constant. However Bohr's atom has many orbits for the electrons.

Answer:

yeasts, moulds, bread, beer, wine, ...

Explanation:

Answer:

Explanation:

The density of a substance can be found by using the formula

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

From the question we have

[tex]density = \frac{18}{24} = \frac{3}{4} \\ [/tex]

We have the final answer as

Hope this helps you