What must happen for an electron to return to its original energy level from a
higher energy level?

A. It must release photons.
B. It must absorb photons.
C. It must absorb electrical energy.
D. It must emit electrical energy.

Answer:

PCl5 <-> PCl3 + Cl2

PCl5 decomposes into PCl3 and Cl2 according to the equation above. A pure sample of Pcl5 is placed in a rigid, evacuated 1.00 L container. The initial pressure of the PCl5 is 1.00 atm. The temperature is held constant until the PCl5 reaches equilibrium with its decomposition products. The figures below show the initial and equilibrium conditions of the system.

As the reaction progresses toward equilibrium, the rate of the forward reaction

A) increases until it becomes the same as the reverse reaction rate at equilibrium

B) stays constant before and after equilibrium is reached

C) decreases to become a constant nonzero rate at equilibrium

D) decreases to become zero at equilibrium

Explanation:

At equilibrium, both forward and backward reactions take place with constant speed.

The reaction will never cease.

Due to this reason chemical equilibrium is called dynamic in nature.

At equilibrium:

the rate of forward reaction = rate of backward reaction

As the reaction progresses toward equilibrium, the rate of the forward reaction decreases to become a constant nonzero rate at equilibrium.

Answer is option C).

When a system is in a state of chemical equilibrium, neither the reactant concentration nor the product concentration changes over time, nor does the system exhibit any further changes in its attributes. Here the correct option is C.

The system reaches a condition of chemical equilibrium when the rate of the forward reaction equals the rate of the reverse reaction. The system is considered to be in a state of dynamic equilibrium when the concentrations of the reactants and products do not change further as a result of the equal rates of the forward and reverse processes.

Equilibrium is impacted by a number of variables, including temperature, pressure, and the system's concentration. Here at equilibrium the rate of the forward reaction decreases to become a constant nonzero rate at equilibrium.

Thus the correct option is C.

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Answer:

Gain energy, move less, become closer together

Answer:

Sodium atoms due to being smaller in size have high ionization energy and thus, it can't lose electrons easily and is more stable and less reactive. ... Hence, from this it is clear that sodium is less reactive than potassium.

Explanation:

Answer:

Its the first one

Explanation:

4 mol is the highest of the Bunch and 4.0L is the lowest making the first answer the correct one

Answer:

D

hope it helps:)))!!!!!!

The concept Planck's quantum theory of radiation is used here to determine the wavelength of the light. The wavelength of the light with 4.01 x 10⁻¹⁹ J of energy is 496 nm . The correct option is B.

According to Planck's quantum theory, different atoms and molecules can emit or absorb energy in discrete amount only. The smallest amount of energy which can be emitted or absorbed in the form of electromagnetic radiation is called quantum.

The energy of the radiation absorbed or emitted is directly proportional to the frequency of the radiation. It is given by the equation:

E = hν

ν = E / h

4.01 x 10⁻¹⁹ J / 6.626 x 10⁻³⁴ = 6.05 × 10¹⁴ Hz

We have,

ν = c / λ

λ = c / ν

3.00 x 10⁸  /  6.05 × 10¹⁴ = 4.958 × 10⁻⁷ m

1 nm = 1 × 10⁻⁹ m

4.958 × 10⁻⁷ m = 495.8 nm = 496 nm

Thus the correct option is B.

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Answer: The equilibrium will shift in the direction of [tex]NH_3[/tex]

Explanation:

The chemical equation for the aqueous solution of ammonia follows:

[tex]NH_3+H_2O\rightleftharpoons NH_4^++OH^-[/tex]

According to Le-chtelier's principle:

If there is any change in the variables of the reaction, then the equilibrium will shift in that direction of equilibrium to minimize the effect.

If we add more amount of [tex]NH_4^+[/tex] to the solution, more of the products will be present. But according to Le-chtelier's principle, to minimize this effect, the equilibrium will shift in the backward direction that in the direction of [tex]NH_3[/tex]

Hence, the equilibrium will shift in the direction of [tex]NH_3[/tex]

Answer:

First oil well in the United States, built in 1859 by Edwin L. Drake, Titusville, Pennsylvania.

Answer:

1.3 × 10²⁵ atoms

Explanation:

Step 1: Calculate the volume of an apple

The radius of an apple is 3.5 cm (3.5 × 10⁻² m). If we assume it is a sphere, we can calculate its volume using the following expression.

V = 4/3 × π × r³

V(apple) = 4/3 × π × (3.5 × 10⁻² m)³ = 1.8 × 10⁻⁴ m³

Step 2: Calculate the volume of 1 atom

The radius of 1 atom is 1.5 A (1.5 × 10⁻¹⁰ m). If we assume it is a sphere, we can calculate its volume using the following expression.

V = 4/3 × π × r³

V(atom) = 4/3 × π × (1.5 × 10⁻¹⁰ m)³ = 1.4 × 10⁻²⁹ m³

Step 3: Calculate how many atoms are in 1 apple.

V(apple)/V(atom) = 1.8 × 10⁻⁴ m³/1.4 × 10⁻²⁹ m³ = 1.3 × 10²⁵

Answer:

C. an element

Explanation:

Elements are pure substances and made up of only one type of atoms which cannot be further broken down.

Answer: -3112 kJ of heat will be released when 5 moles of nitrogen is produced.

Explanation:

We are given:

Moles of nitrogen = 5 moles

Given chemical reaction follows:

[tex]N_2H_4+O_2\rightarrow N_2+2H_2O;\Delta H=-622.4 KJ[/tex]

By stoichiometry of the reaction:

If 1 mole of nitrogen gas is produced, the heat released is -622.4 kJ

So, if 5 moles of nitrogen gas is produced, the heat released will be = [tex]\frac{-622.4kJ}{1mol}\times 5mol=-3112kJ[/tex]

Hence, -3112 kJ of heat will be released when 5 moles of nitrogen is produced.

Answer: The final temperature will be [tex]23^oC[/tex]

Explanation:

Calculating the heat released or absorbed for the process:

[tex]q=m\times C\times (T_2-T_1)[/tex]

In a system, the total amount of heat released is equal to the total amount of heat absorbed.

[tex]q_1=-q_2[/tex]

    OR

[tex]m_1\times C_1\times (T_f-T_1)=-m_2\times C_2\times (T_f-T_2)[/tex]           ......(1)

where,

[tex]C_1[/tex] = specific heat of aluminium = [tex]0.21 Cal/g^oC[/tex]

[tex]C_2[/tex] = heat capacity of water = [tex]1Cal/g^oC[/tex]

[tex]m_1[/tex] = mass of aluminium = 30. g

[tex]m_2[/tex] = mass of water = 50. g

[tex]T_f[/tex] = final temperature of the system = ?

[tex]T_1[/tex] = initial temperature of aluminium = [tex]40.^oC[/tex]

[tex]T_2[/tex] = initial temperature of the water = [tex]21.^oC[/tex]

Putting values in equation 1, we get:

[tex]30\times 0.21\times (T_f-40)=-50\times 1\times (T_f-21)\\\\56.3T_f=1302\\\\T_f=\frac{1302}{56.3}=23.13^oC=23^oC[/tex]

Hence, the final temperature will be [tex]23^oC[/tex]

Answer:

D.Protien

Explanation:

DNA has four nucleobases: adenine, thymine, guanine, and cytosine. The nucleobases in a DNA strand have preferred partners to form hydrogen bonds with. Cytosine pairs with guanine, and adenine pairs with thymine. These are the base pairing rules that allow DNA replication and protein synthesis to happen.

The reaction that can be used to extract copper metal from copper sulfate solution would be equation 2.

Fe will displace Cu from CuSO4 because it is more reactive. In other words, Fe ranks higher than Cu in the reactivity series.

Thus:    [tex]Fe + CuSO_4 ---> Cu + FeSO_4[/tex]

Even though Na will displace Cu from CuSO4, equation 1 will result in the formation of Cu(OH)2 instead of free Cu because it is a double replacement reaction.

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Answer: sorry its lagging i hope this help fore 18.. =D

Explanation:

n,s is repeating the cycle of the inside

Answer/Explanation:

18, a,

I believe the n, and s represents North, South, or just the way the arrows are rotating repeatedly.

18, b,

The phenomenon re-occurring shows the alignment of magnetic dipoles with in a magnet, like inside. The arrows show a direction in the line with an external magnetic field in a way that it can produce its own magnetic fields that seem to travel from North to the South.

18, c,

Incorrect. Refrigerator magnets have multiple layers of magnification, they use opposite polarities to stay this way. If he puts the magnet sideways it may stick to the fridge

~ LadyBrain

Answer:

Give an example of each of the following chemical changes.

(a) A photochemical reaction involving

(i) silver salt

(ii) water

(b) A reaction involving

(i) blue solution

(ii) formation of dirty green precipitate

(c) Two gases combine to form white solid.

(d) A reaction where colour change is noticed.​

Explanation:

a) A photochemical reaction involving  silver salt is used in black and white photography.

AgCl breaks down and converts into Ag during this photochemical reaction.

(ii) Photochemicalreaction involving water takes place in plants during the photosynthesis process.

Plants prepare food(carbohydrate) by using sunlight water and CO2 gas.

(b) A reaction involving

(i) blue solution:

For example reaction of copper sulfate solution with an iron nail.

When an iron nail is placed in CuSO4 blue color solution, then it changes to green color and reddish-brown solid deposits at the bottom of the container.

(ii) Reaction of ferrous sulfate with NaOH forms a dirty green precipitate of ferrous hydroxide.

(C) Two gases combine and form a white solid:

For example when HCl gas reacts with ammonia gas, then a white solid of ammonium chloride will be formed.

(d)  A reaction where the color change is noticed.:

When an iron nail is placed in CuSO4 blue color solution, then it changes to green color and reddish-brown solid deposits at the bottom of the container.

Answer:

JWBVH

Explanation:

NWSBWHSBHS

Answer:

B

Explanation:

When the electron goes up levels it absorbs energy to enter that higher energy state. When it goes down, it releases energy but just not as much because 1-4 is more than 4-2.

Answer:

Ionic compounds are crystalline solids, soluble in water and conduct electricity when molten or in solution. These characteristics are due to the type of link that holds them together.

The complete question is as follows: 2 molecules of potassium chlorate (KClO3) form 2 molecules of potassium chloride (KCl) and 3 molecules of oxygen (O2). Write a balanced equation for this reaction?

Answer: The balanced chemical equation is [tex]2KClO_{3} \rightarrow 2KCl + 3O_{2}[/tex].

Explanation:

A balanced equation is defined as the equation which contains same number of atoms on both reactant and product side when a chemical reaction occurs.

Hence, when 2 molecules of potassium chlorate [tex](KClO_{3})[/tex] form 2 molecules of potassium chloride (KCl) and 3 molecules of oxygen [tex](O_{2})[/tex] then its balanced equation will be as follows.

[tex]2KClO_{3} \rightarrow 2KCl + 3O_{2}[/tex]

Here, number of atoms on the reactant side as as follows.

Number of atoms on the product side are as follows.

Since, the number of atoms on reactant side are equal to the number of atoms on product side. So, this reaction equation is balanced.

Thus, we can conclude that the balanced chemical equation is [tex]2KClO_{3} \rightarrow 2KCl + 3O_{2}[/tex].

Answer:

5.1 moles of P2O3 are required

Explanation:

Based on the reaction, 1 mole of diphosphorus trioxide, P2O3, reacts with 3 moles of water to produce 2 moles of phosphorous acid, H3PO3. That means the conversion factor is: 1mol P2O3 = 2mol H3PO3.

The moles of P2O3 required to produce 10.2mol H3PO3 are:

10.2mol H3PO3 * (1mol P2O3 / 2mol H3PO3) =

Answer:B.  as a mineral is a deposit of fine materials it would not contain decayed materials without outside assistance

Answer: The equilibrium constant for the reverse reaction at the same temperature is [tex]2.40 \times 10^{33}[/tex].

Explanation:

The given reaction equation is as follows.

[tex]2HCl(g) \rightleftharpoons H_{2}(g) + Cl_{2}(g)[/tex] ... (1)

It's equilibrium constant (K) value is [tex]4.17 \times 10^{-34}[/tex].

Also, another reaction equation is as follows.

[tex]H_{2}(g) + Cl_{2}(g) \rightleftharpoons 2HCl(g)[/tex]

This is the reverse of equation (1). Hence, its equilibrium value is calculated as follows.

[tex]K' = \frac{1}{K}\\= \frac{1}{4.17 \times 10^{-34}}\\= 2.40 \times 10^{33}[/tex]

Thus, we can conclude that the equilibrium constant for the reverse reaction at the same temperature is [tex]2.40 \times 10^{33}[/tex].

Answer:

The correct option is option C

Explanation:

Loss or gain of electron(s) occurs in a type of attraction known as electrovalent or ionic attraction. In this type, there is transfer (or loss) of electron(s) from a metal atom to become positively charged while a nonmetal accepts (or gains) this electron to become negatively charged.

When this does not happen, two metal atoms can become attached by sharing the same electrons through a form of attraction known as covalent bonding. Here, the two atoms share electrons (known as shared pair) together to achieve there octet configuration on the outermost shell.  

Answer:

The amount of water

The amount of sugar and

The amount of yeast

Explanation:

A constant variable is that variable in an experiment which must be kept the same for all groups in order not to alter the results of the experiment.

In this question, the independent variable i.e. the variable being manipulated is the TYPE OF SUGAR USED while the dependent variable i.e. variable that responds to change is AMOUNT OF ENERGY. Three different types of sugar were used viz: maltose, glucose, and sucrose. To not alter the outcome of the experiment, the constants of this experiment i.e. variables that must be the same for all groups of the experiment, include the following:

- The amount of water

- The amount of sugar

- The amount of yeast used

Answer:

the answer is C) higher concentration of water in the soil than in the root hairs

Explanation:

Answer:

the answer is c

Explanation:

i just got it

Answer: A 0.20 M solution of HCl with a volume of 15.0 mL is exactly neutralized by the 0.10 M solution of NaOH with 3 mL volume.

Explanation:

Given: [tex]M_{1}[/tex] = 0.20 M,      [tex]V_{1}[/tex] = 15.0 mL

[tex]M_{2}[/tex] = 0.10 M,            [tex]V_{2}[/tex] = ?

Formula used is as follows.

[tex]M_{1}V_{1} = M_{2}V_{2}[/tex]

Substitute the values into above formula s follows.

[tex]M_{1}V_{1} = M_{2}V_{2}\\0.20 M ]times 15.0 mL = 0.10 M ]times V_{2}\\V_{2} = 30 mL[/tex]

Thus, we can conclude that a 0.20 M solution of HCl with a volume of 15.0 mL is exactly neutralized by the 0.10 M solution of NaOH with 3 mL volume.

Answer: