the difference in energy between the n=1 and n=2 energy levels in a hydrogen atom is 1.64x10^-18 J. what happens when an electron in a hydrogen atom transitions from n=2 to n=1?

Answer:

A.

Explanation:

elctrolytes decomposes

Answer:

D. ionizes

Explanation:

The answer option which is not a necessary input for the process of photosynthesis is: D. [tex]O_2[/tex] (oxygen)

Photosynthesis can be defined as a biological and chemical process through which living organisms such as green plants, transform light energy (sunlight) into chemical energy.

Basically, both sunlight, carbon dioxide ([tex]C0_2[/tex]) and water ([tex]H_2O[/tex]) contained in the Earth's atmosphere plays a significant role in photosynthesis because they serve as an input.

Hence, the necessary input for the process of photosynthesis to take place include the following:

In conclusion, [tex]O_2[/tex] (oxygen) is an end product (output) of photosynthesis rather being an input.

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Answer: Results will tell you which hypothesis is true.

Explanation: The hypothesis becomes a theory if the results support it. d.A new experiment is designed to provide additional data about the hypothesis. Imagine that a team of scientists test a certain hypothesis, and the experimental results show that it is false. ... The results will show which other hypotheses must be true.

Heat capacity of Calorimeter = 10.7 J/°c

Heat lost=Heat gained

Q in = Q out

-Q lost(hot water)=Q gained (cold water+calorimeter)

-m.c.Δt=m.c.Δt+C.Δt

[tex]\tt \rightarrow -50\times 4.18\times (32.7-43)=50\times 4.18\times (32.7-22.9)+(32.7-22.9)\times C_{cal}\\\\\rightarrow 2152.7=2048.2+9.8\times C_{cal}\\\\104.5~J=9.8\times C_{cal}\\\\C_{cal}=\dfrac{104.5}{9.8}=10.7~J/^oC[/tex]

Answer:

Natural science can be divided into two main branches

Explanation:

life science and physical science. Life science is alternatively known as biology, and physical science is subdivided into branches: physics, chemistry, astronomy and Earth science.

Answer:

Astronomy  

Biology

Geology

Chemistry

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Answer:

(a). Kindly check the explanation section.

(b). 24.5 M^-1 cm^-

(c). 0.0318 M

Explanation:

So, we are given the following data parameters which is going to aid us in solving the above Question;

The path length = 1cm, extinction coefficient = unknown, absorbance is unknown and concentration= 0.02mM.

Using the formula below; we can determine the extinction coefficient as;

Absorbance = extinction coefficient × concentration × path length. -----------(1).

(a). Since, the absorbance is not given in the Question it won't be possible to determine the value of the extinction coefficient. Thus, say the value of absorbance = A.

Then, extinction coefficient = A/ 0.02 × 1 cm.

(b). Making use of the formula above, the extinction coefficient can be Determine as follows;

extinction coefficient = 1.84/0.075 × 1 = 24.5 M^-1 cm^-1.

(c). The concentration can be Determine by also making use of the formula above and making the concentration the subject of the formula;

Concentration = absorbance/ extinction coefficient × path length.

Concentration = 0.78/24.5 M^-1 cm^-1. × 1cm = 0.0318 M.

Answer:

A: melting point and the other one is i think element

Answer:

1.3 moles of HNO₃ will be produced

Explanation:

Equation for the reaction:

3NO₂ + H₂O ----> 2HNO₃ + NO

From the equation of the reaction, 3 moles of NO₂ reacts with 1 mole of H₂O to produce 2 moles of HNO₃

Suppose there are 2 moles of NO₂  and 7.0 moles of H₂O in a reactor, the limiting reactant will be NO₂ and H₂O will be in excess since 3 moles of NO₂ reacts with every 1 mole of H₂O.

Since 3 moles of NO₂ reacts to produce  2 moles of HNO₃;

2 moles of NO₂ will react to produce 2/3 * 2 moles HNO₃ = 1.3 moles of HNO₃

Therefore, 1.3 moles of HNO₃ will be produced

The largest amount of HNO₃ produced from the reaction between 2 mole of NO₂ and 7.0 mole of H₂O in a reactor is 1.3 mole

We'll begin by determining the limiting reactant. This can be obtained as follow:

3NO₂ + H₂O —> 2HNO₃ + NO

From the balanced equation above,

3 moles of NO₂ reacted with 1 mole of H₂O.

Therefore,

2 moles of NO₂ will react with = [tex]\frac{2}{3}\\\\[/tex] = 0.67 mole of H₂O.

From the balanced equation above,

3 moles of NO₂ reacted to produce 2 moles of HNO₃.

Therefore,

2 moles of NO₂ will react to produce = [tex]\frac{2 *2 }{3} \\\\[/tex] = 1.3 mole of HNO₃.

Thus, the largest amount of HNO₃ produced from the reaction is 1.3 mole

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Answer:

the action or process of filtering something.

Explanation:

Filtration is a physical, biological or chemical operation that separates solid matter and fluid from a mixture with a filter medium that has a complex structure through which only the fluid can pass.

Answer:

M = 184.1 g/mol

Explanation:

Given data:

Density = 5.95 g/L

Temperature = 100°C (100+273 = 373 K)

Pressure = 755 mmHg = (755/760 = 0.99 atm )

Molar mass of gas = ?

Formula:

d = PM/RT

Solution:

M = dRT / P

M = 5.95 g/L × 0.0821 atm.L/mol.K  × 373 K/ 0.99 atm

M = 182.21atm.g/mol / 0.99 atm

M = 184.1 g/mol

Answer:

Kb = 1.6 × 10⁻⁵

Explanation:

Step 1: Given data

Acid dissociation constant of hydrocyanic acid (Ka): 6.2 × 10⁻¹⁰

Concentration of cyanide ion (Cb): 0.1 M

Step 2: Calculate the basic dissociation constant (Kb) of cyanide ion

We have the Ka of HCN. We can calculate the Kb of its conjugate base using the following expression.

Ka × Kb = Kw = 1.0 × 10⁻¹⁴

Kb = 1.0 × 10⁻¹⁴/Ka

Kb = 1.0 × 10⁻¹⁴/6.2 × 10⁻¹⁰

Kb = 1.6 × 10⁻⁵

The  Kb for a 0.1 M solution of cyanide ion is :

- 1.6 × 10⁻⁵

Given:

Acid dissociation constant of hydrocyanic acid (Ka)= 6.2 × 10⁻¹⁰

Concentration of cyanide ion (Cb)= 0.1 M

Base dissociation constant (kb)=?

Ka × Kb = Kw = 1.0 × 10⁻¹⁴

Kb = 1.0 × 10⁻¹⁴/Ka

Kb = 1.0 × 10⁻¹⁴/6.2 × 10⁻¹⁰

Kb = 1.6 × 10⁻⁵

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Answer:

The main function of the immune system is to provide immunity to the body. Immunity is the body's ability to protect itself from the pathogens it is exposed to. Immunity depends on the body's ability to differentiate between things that belong in the body and those that do not. The immune system's first line of defense includes physical and chemical barriers that are always ready and prepared to defend the body from infection.

The skin acts as a barrier against pathogens. Some structures of the first line of defense include the skin, mouth, eyes, ears, nose, and stomach. The skin produces sweat and oil that work together to keep pathogens from the entering the body. Saliva and tears contain substances the can destroy pathogens. The ears and the stomach help fight pathogens.The ears produce ear wax that prevent pathogens from entering the ears. The stomach produces a liquid the kills pathogens.

Mucus is produce by the nose, lungs, throat, and stomach. Mucus traps pathogens. Mucus also prevent pathogens from getting into deep tissues. Anyway, the very first line of defense against any invasion of the human body is a set of physical barriers between the inside of the body and the outer world.

*my notes from edge2020*

Hope this helps ^-^

Answer:

C₂H₂(g) + 2.5 O₂(g) ⇒ 2 CO₂(g) + H₂O(l)   ΔH° = -1300 kJ/mol

Explanation:

In the combustion of acetylene, it reacts with oxygen to produce carbon dioxide and water. The corresponding chemical equation is:

C₂H₂(g) + 2.5 O₂(g) ⇒ 2 CO₂(g) + H₂O(l)

The thermochemical equation includes the balanced chemical equation, stating the states of aggregation and the enthalpy of the reaction.

C₂H₂(g) + 2.5 O₂(g) ⇒ 2 CO₂(g) + H₂O(l)   ΔH° = -1300 kJ/mol

The enthalpy : 320.3 kJ/mol

The change in enthalpy in the formation of 1 mole of the elements is called enthalpy of formation  

The enthalpy of formation measured in standard conditions (25 ° C, 1 atm) is called the standard enthalpy of formation (ΔHf °)  

Based on the principle of Hess's Law,

the change in enthalpy of a reaction will be the same even though it is through several stages or ways  

Reaction

2Fe (s) + 3Cl₂ (g) → 2FeCl₃ (s) ∆H° = -800.0 kJ/mol  x 2

4Fe (s) + 6Cl₂ (g) → 4FeCl₃ (s) ∆H° = -1600.0 kJ/mol

Si(s) + 2 Cl₂ (g) → SiCl₄ (s) ∆H° = -640.1 kJ/mol

Reverse

SiCl₄ (s) → Si(s) + 2 Cl₂ (g) ∆H° = 640.1 kJ/mol x 3

3SiCl₄ (s) → 3Si(s) + 6Cl₂ (g) ∆H° = 1920.3 kJ/mol

------------------------------------------------------------------------ +

3 SiCl₄ (s) + 4 Fe (s) → 4 FeCl₃ (s) + 3 Si (s) ∆H° = 320.3 kJ/mol

The enthalpy for the formation of 4 moles of [tex]\rm FeCl_3[/tex] has been 320.3 kJ/mol.

The enthalpy of formation of 1 mole at standard temperature and pressure has been termed the standard enthalpy of formation.

The reaction enthalpy to be calculated has reactants of 3 moles of [tex]\rm SiCl_4[/tex], and 4 moles of Fe.

The enthalpy for the formation of [tex]\rm SiCl_4[/tex] has been -640.1 kJ/mol.

The enthalpy for the dissociation of [tex]\rm SiCl_4[/tex] has been the reverse of the formation reaction = +640.1 kJ/mol.

The enthalpy for the dissociation of 3 moles of [tex]\rm SiCl_4[/tex] has been = 3 [tex]\times[/tex] 640.1 kJ/mol.

The enthalpy for the dissociation of 3 moles of [tex]\rm SiCl_4[/tex] has been = 1920.3 kJ/mol.

The enthalpy for the formation of 2 moles of [tex]\rm FeCl_3[/tex] = -800 kJ/mol

The enthalpy for the formation of 4 moles of [tex]\rm FeCl_3[/tex] = -1600 kJ/mol.

The final reaction has 3 moles of  [tex]\rm SiCl_4[/tex], and 4 moles of [tex]\rm FeCl_3[/tex].

Thus, the final enthalpy of reaction will be: 1920 kJ/mol + (-1600 kJ/mol)

The final enthalpy of reaction will be = 320.3 kJ/mol.

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Answer:

(a) > (d) > (c) > (b)

Explanation:

Acidic character is based upon inductive effect of the functional group that are attached to parent chain.

1. Nitro is a -I group which makes phenol acidic due to increased resonance,  2. bromine is a -I group but it is weaker than nitro group

3. phenol is more acidic than cyclohexanol due to resonance stabilization of resonance and among halogen F>Cl>Br>I is the order of acidity

4. cyclohexanol will be weakest as  it is not associated with any -I groups here.

so the order of acidity will be

(a). 4-nitropheno >  (d). 4-bromophenol > (c). 2,6-difluorocyclohexanol  >               (b). cyclohexanol

Answer: CH4

Explanation:

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Answer:

O₂

Explanation:

The example of the compound or the molecule that forms a non-polar bond is oxygen gas.

Oxygen gas has a formula of O₂

Answer:

The temperature of the Nitrogen after throttling is  [tex]T_2 = 300 \ K[/tex]

Explanation:

From the question we are told that

   The  temperature is  [tex]T_1 = 300 \ K[/tex]

    The pressure is  [tex]P = 200 \ kPa = 200 * 10^{3} \ Pa[/tex]

    The pressure after being  [tex]P_1 = 100 \ kPa = 100 * 10^{3} \ Pa[/tex]

Generally from the first law of thermodynamics we have that

      [tex]Q - W = \Delta U + \Delta K[/tex]

Here [tex]\Delta U[/tex]  is the change internal  energy which is mathematically represented as

            [tex]\Delta U = C_p (T_2 - T_1)[/tex]

Here      [tex]C_p[/tex] is the specific heat of the gas at constant pressure

        [tex]\Delta K[/tex]  is the change kinetic energy which is negligible

         Q  is the thermal  energy  which is Zero for an adiabatic process

         W  is the work done and the value is zero given that the gas was throttled adiabatically

So

      [tex]0= \Delta U +0[/tex]

=>   [tex]\Delta U = 0[/tex]

=>  [tex](T_2 - 300) = 0[/tex]

=>   [tex]T_2 = 300 \ K[/tex]

Answer:

1 oxygen and 2 hydrogen

Answer:

167in

Explanation:

Given arithmetic;

        56.5in + 95.3in + 15in

To determine the correct significant digits, the sum cannot be more precise than the least precise value in the addition;

 The least precise is 15in and it is in 2significant places;

      56.5in

      95.3in

 +    15    in

......................

      166.8in

......................

The value is 167in

Answer:

Fluorine

Explanation:

Fluorine is the "best" at removing electrons because it has 5 electrons on its second shell. The 5 electrons are really close and are trying to drag in another electron to complete the shell and have all 6 electrons to complete the valence shell.

Answer:

Manganese (Mn)

Explanation:

We know it's manganese because we are told it is an electrically neutral atom. This means it has the same number of protons and electrons. If it has 25 electrons, it has 25 protons. Protons tell us the atomic number of the atom, which also tells us the name of the element. Manganese is element 25 on the periodic table.

Answer:

[tex]M_{acid}=0.08892M[/tex]

Explanation:

Hello!

In this case, since the reaction between arsenic acid and potassium hydroxide is:

[tex]H_3AsO_4+3KOH\rightarrow K_3AsO_4+3H_2O[/tex]

Thus, since the mole ratio between the acid and the base is 1:3, at the equivalence point we can write:

[tex]3n_{acid}=n_{base}[/tex]

That in terms of molarities and volumes is:

[tex]3M_{acid}V_{acid}=M_{base}V_{base}[/tex]

Thus, the concentration of the arsenic acid is:

[tex]M_{acid}=\frac{M_{base}V_{base}}{3V_{acid}}=\frac{0.1894M*35.21mL}{3*25.00mL} \\\\M_{acid}=0.08892M[/tex]

Best regards!

The concentration (M) of arsenic acid in a solution of 25.00 mL is 0.088M.

Molarity of any solution will be calculated as:

M = n/V, where

V = volume

n is the moles and it will be calculated as:
n = W/M, where

W = given mass

M = molar mass

Given chemical reaction is:

H₃AsO₄ + 3KOH → K₃AsO₄ + 3H₂O

Moles of 35.21 mL of 0.1894 M KOH will be calculated as:

n = (0.1894)(0.035) = 0.0066 moles

From the stoichiometry of the reaction it is clear that:

1 mole of H₃AsO₄ = react with 3 moles of KOH

0.0066 moles of KOH = react with 1/3×0.0066= 0.0022 moles of H₃AsO₄

Now we calculate the molarity of H₃AsO₄ in 25mL of solution as:

M = 0.0022/0.025 = 0.088 M

Hence, required molarity is 0.088 M.

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Answer:

Explanation:

Answer:

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mass = 20.48 g

moles=0.1895

In general, the gas equation can be written  

where  

P = pressure, atm  

V = volume, liter  

n = number of moles  

R = gas constant = 0.08205 L.atm / mol K  

T = temperature, Kelvin  

P=0.23 atm

V=20 L

T=23+273=296 K

[tex]\tt n=\dfrac{PV}{RT}=\dfrac{0.23\times 20}{0.082\times 296}=0.1895[/tex]

mass SF₄ (MW=108,07 g/mol) :

[tex]\tt 0.1895\times 108,07 g/mol=20.48~g[/tex]

Answer:

A circle graph, or a pie chart, is used to visualize information and data. A circle graph is usually used to easily show the results of an investigation in a proportional manner. Bar graphs are used to compare things between different groups or to track changes over time. However, when trying to measure change over time, bar graphs are best when the changes are larger.

Explanation:

In short, bar graphs are better to keep track of data over long periods of time, and circle graphs are better when you are trying to visualize a specific set of data.

Circle graph can be also be called pie chart, which  is more widely used. It is usually made up of a circle, divided into parts or pies. In the divided parts, it is used to differentiate between different data.

Bar charts on the other hand are like graphs having both x and y axis. It is used to represent data with respect to the height of the graph. Each data is divided into different smaller parts on the graph.

Example of what they look like is attached below.

First one is bar chart while the second is a circle graph

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