Which of these statements is true?


1. Electrons reach higher energy levels when they move closer to the nucleus.


2. An electron can absorb energy only from light.


3. The spectrum of hydrogen consists of all frequencies of radiation.


4. The emission spectrum of each element is unique

Answers

Answer 1
I think is number 4

Related Questions

What is the correct molecular geometry for NBr2F?

Answers

Answer:

Molecular geometry of o3

Ozone has three electron groups around the central oxygen, so has the trigonal planar electron geometry. The molecular geometry is bent: The Effect of Lone Pairs (contd.) With four electron groups (tetrahedral electron geometry), there can be one or two lone pairs around the central atom.

What is the mass, in grams, of a piece of aluminum if its temperature changes from 25.0 ºC to 31.5 ºC when it absorbs 42.2 joules of energy? The specific heat for aluminum is 0.89J/gºC

Answers

Answer:

m = 7.29 grams

Explanation:

Given that,

Initial temperature, T₁ = 25ºC

Final temperature, T₂ = 31.5ºC

The specific heat of the metal is 0.89 J/gºC.

We know that the heat released due to the change in temperature is given by :

[tex]Q=mc\Delta T\\\\m=\dfrac{Q}{c\Delta T}\\\\m=\dfrac{42.2 }{0.89\times (31.5-25)}\\\\m=7.29\ g[/tex]

So, the mass of the piece is equal to 7.29 grams.

PLEASE HURRY I WILK TIVE BRAINYEST
What is the weather like in a temperate grassland? (Select all that apply.)
A) summers are mild to hot
B) winters are cold
C) summers are cool
D) winters are mild

Answers

Answer:

A. Summers are mild to hot, B. Winters are cold.

It would probably be A

What is the initial and final mass of the zinc and copper?

Answers

Answer:the final mass of copper is  3.84 g. There was an increase in mass of 1.84 g from the initial mass of 2.0 g.

Explanation:

What are the substances that interact to form new substances in a chemical reaction called?
A. Reactants
B. Products
C. Chemicals
D. Substances

Answers

Answer:

A. Reactants

Explanation:

A chemical reaction is the process in which atoms present in the starting substances rearrange to give new chemical combinations present in the substances formed by the reaction. These starting substances of a chemical reaction are called the reactants, and the new substances that result are called the products.

What is [H⁺] in a 0.330 M solution of acrylic acid, CH₂CHCOOH (Ka = 3.16 × 10⁻⁵)?

Answers

Answer:

[H⁺] = 3.23x10⁻³ M

Explanation:

For a weak monoprotic acid, such as acrylic acid, we can calculate [H⁺] using the following formula if the solution concentration is significantly higher than the Ka:

[H⁺] = √(C * Ka)

Where C is the weak acid concentration.

We input the data:

[H⁺] = [tex]\sqrt{0.330 M * 3.16x10^{-5}}[/tex]

And solve for [H⁺]:

[H⁺] = 3.23x10⁻³ M

What is the percent yield of a reaction producing 26g Iridium V Sulfate from 30g Lithium Sulfate and 30g Iridium V Carbonate?

Answers

The sulphate solutions came from a recycling LIBs waste cathode materials, which were done by previous research; their content is shown in Table 1 [18]. Sodium carbonate (Na2CO3) was purchased from Nihon Shiyaku Reagent, Tokyo, Japan (NaCO3, 99.8%), for the chemical precipitation. CO2 was purchased from Air Product and Chemical, Taipei, Taiwan (CO2 ≥ 99%), to carry out the hydrogenation–decomposition method. Dowex G26 was obtained from Sigma-Aldrich (St. Louis, MO, USA) and was used as a strong acidic cation exchange resin, to remove impurities. Multi-elements ICP standard solutions were acquired from AccuStandard, New Haven, Connecticut State, USA. The nitric acid (HNO3) and sulfuric acid (H2SO4) were acquired from Sigma-Aldrich (St. Louis, MO, USA) (HNO3 ≥ 65%) (H2SO4 ≥ 98%) The materials were analyzed by energy-dispersive X-ray spectroscopy (EDS; XFlash6110, Bruker, Billerica, MA, USA), X-ray diffraction (XRD; DX-2700, Dangdong City, Liaoning, China), scanning electron microscopy (SEM; S-3000N, Hitachi, Tokyo, Japan), and inductively coupled plasma optical emission spectrometry (ICP-OES; Varian, Vista-MPX, PerkinElmer, Waltham, MA, USA). In order to

Appl. Sci. 2018, 8, 2252 3 of 10
control the hydrogenation temperature and heating rate, a thermostatic bath (XMtd-204;

A certain reaction has an activation energy of 51.02 kJ/mol. At what Kelvin temperature will the reaction proceed 4.50 times faster than it did at 365 K

Answers

Answer:

[tex]T_2=400.73K[/tex]

Explanation:

From the question we are told that:

Activation energy [tex]E_a= 51.02 kJ/mol.=>51.02*10^3J/mol[/tex]

Reaction Ratio [tex]\triangle K=4.50[/tex]

Initial Temperature [tex]T_1=365K[/tex]

Generally the equation for Final Temperature [tex]T_2[/tex] is mathematically given by

 [tex]log \triangle K=\frac{E_a}{2.303R}*(\frac{T_2-T_1}{T_1T_2})[/tex]

Where

 [tex]R=Gas constant[/tex]

 [tex]R =8.3143[/tex]

Therefore

 [tex]log 4.50=\frac{51.2*10^3}{2.303*8.31432}*(\frac{T_2-365}{365*T_2})[/tex]

 [tex]log 4.50=7.328*\frac{T_2-365}{T_2}[/tex]

 [tex]0.0892=\frac{T_2-365}{T_2}[/tex]

 [tex]0.0892T_2=T_2-365[/tex]

 [tex]365=T_2-0.0892T_2[/tex]

 [tex]365=0.91T_2[/tex]

 [tex]T_2=\frac{365}{0.91}[/tex]

 [tex]T_2=400.73K[/tex]

Be sure to answer all parts. Determine the electron-group arrangement, molecular shape, and ideal bond angle for the following molecule: SO3 Electron-group arrangement: V-shaped (bent) trigonal planar trigonal pyramidal seesaw Molecular shape: bent square pyramidal trigonal planar trigonal pyramidal Ideal bond angle: degrees

Answers

Answer:

trigonal planar

Explanation:

The molecule SO3 is of the type AX3. The molecule is symmetrical and non polar.

There are three regions of electron density in the molecule. This corresponds to a trigonal planar geometry. This means that the three oxygen atoms are arranged at the corners of a triangle.  The bond angle is 120 degrees.

Suppose you needed to explain the concept of the mole to a junior high school student. What would you tell them?

Answers

Answer:

Explanation:

duehgjvcujhyeq bvckjfdsaeb gjdksghUIBGREQWMNHGTRE BAGTFEQA

What is the mass of 4 × 1015 atoms of nickel
(Ni)?
Answer in units of g.

Answers

It would probably be 4060

Only electrons in the __________ orbital can form chemical bonds.

Answers

Answer:

Electrons in sigma bonds remain localized between two atoms. Sigma bond results from the formation of a molecular orbital by the end to end overlap of atomic orbitals. Electrons in pi bonds can become delocalized between more than two atoms. Pi bonds result from the formation of molecular orbital by side to side overlap of atomic orbitals.

help i will mark brainliest

Answers

Answer:

Image A

Explanation:

The hemisphere experiences summer when it is tilted towards the sun. Image a has the northern hemisphere tilted towards the sun.

Answer:

image A

Explanation:

this is because the sun is hitting earth at a steep angle

what is the percent composition of calcium fluoride

Answers

Answer:

78.07

Explanation:

them seperatly is

Calcium Ca 51.333%

Fluorine F 48.667%

On the basis of the information above, what is the approximate percent ionization of HNO2 in a 1.0 M HNO2 (aq) solution?

Answers

Answer:

The answer is "2%"

Explanation:

Equation:

[tex]HNO_2\ (aq) \leftrightharpoons H^{+} \ (aq) + NO_2^{-}\ (aq) \\\\\ K_a = 4.0\times \ 10^{-4}[/tex]

[tex]H^{+}=?[/tex]

Formula:

[tex]Ka = \frac{[H^{+}][NO_2^{-}]}{[HNO_2]}[/tex]

Let

[tex][H^{+}] = [NO_2^{-}] = x[/tex] at equilibrium

[tex]x^2 = (4.0\times 10^{-4})\times 1.0\\\\x = ((4.0\times 10^{-4})\times 1.0)^{0.5} = 2.0 \times 10^{-2} \ M\\\\[/tex]

therefore,

[tex][H^{+}] = 2.0\times 10^{-2} \ M = 0.02 \ M[/tex]

Calculating the % ionization:

[tex]= \frac{([H^{+}]}{[HNO_2])} \times 100 \\\\= \frac{0.02}{1}\times 100 \\\\= 2\%\\\\[/tex]

The approximate percent ionization of HNO₂ in a 1.0 M HNO₂ (aq) solution is 2%.

How we calculate the % ionization?

% ionization of any compound will be calculated as follow:

% ionization = ([ion]/[acid or base]) ₓ 100

Given chemical reaction with ICE table will be represented as:

                           HNO₂(aq) → H⁺(aq) + NO₂⁻(aq)

initial                          1                0             0

change                      -x               +x           +x

equilibrium              1-x                x             x

Equilibrium constant will be represented as:
Ka = [H⁺][NO₂⁻] / [HNO₂]

Acid dissociation constant for HNO₂ = 4×10⁻⁴

Putting all values in the above equation, we get

4×10⁻⁴ = x² / 1-x

Value of changeable quantity is very less, so we neglect from the concentration of HNO₂.

4×10⁻⁴ = x²

x = 2 × 10⁻²

So, the concentration of H⁺ ion = 2 × 10⁻²M

Now we put all these values in the % ionization equation, we get

% ionization = (0.02/1) × 100 = 2%

Hence , % ionization is 2%.

To know more about % ionization, visit the below link:
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can someone answer this

Answers

The correct answer is B 25

2+4 help please i will fail 6th grade

Answers

Answer:

6

Explanation:

lol

According to the kinetic molecular theory which substances are made of particles ?

Answers

Answer:

The kinetic molecular theory of matter states that: Matter is made up of particles that are constantly moving. All particles have energy, but the energy varies depending on the temperature the sample of matter is in. This in turn determines whether the substance exists in the solid, liquid, or gaseous state.

Explanation:

Kinetic molecular theory explains the properties of solids, liquids and gases. As per this theory, matter is made of particles.

What is kinetic theory?

Kinetic molecular theory explains the properties of different states of matter. According to this theory matter is made up of particles. But the theory is mostly applies for gases.

According to kinetic theory  of gases, gaseous substances consists of tiny spherical particles which are located apart from each other and hence no intermolecular force acts between them. They are in random motion and gains kinetic energy.

The kinetic energy of particles are temperature dependant and it increase as temperature rises. The collision between the particles and the particle and wall of the container in which they are will be elastic collision.

These concepts are  applicable only for ideal gases. An less applicable for other states of matter.

To find more kinetic theory, refer here:

https://brainly.com/question/15357425

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How many moles of Oxygen atoms are contained in 45.9 mol CO2?

Answers

Answer:

Explanation:

10 moles of oxygen atoms.\ \textbf{b)} 91.8 moles of oxygen at

1. Enter the complete ionic equation when Li3PO4 and AgNO3 are mixed.2. Enter the net ionic equation when K2SO4 and Na2CO3 are mixed.3. Enter the complete ionic equation when K2SO4 and Na2CO3 are mixed.4. Enter the complete ionic equation when Fe(NO3)2 and Na2CO3 are mixed.5. Enter the net ionic equation when Fe(NO3)2 and Na2CO3 are mixed.6. Enter the complete ionic equation when BaCl2 and KOH are mixed.7. Enter the net ionic equation when BaCl2 and KOH are mixed.

Answers

Solution :

1. Ionic equation when  [tex]$Li_3PO_4$[/tex]  and [tex]$AgNO_3$[/tex] are mixed.

  [tex]$3 Li^+ (aq) + PO_4^{3-} (aq) + 3Ag^+ (aq) + 3NO_3^-(aq) \rightarrow Ag_3PO_4(s)+3Li^+(aq)+3NO_3^-(aq)$[/tex]

Net ionic :  [tex]$PO_4^{3-}(aq)+3 ag^+(aq) \rightarrow Ag_3PO_4(s) $[/tex]

2. [tex]$K_2SO_4$[/tex] and [tex]$Na_2CO_3$[/tex]

  No reaction

3. [tex]$K_2SO_4$[/tex] and [tex]$Na_2CO_3$[/tex]

  No reaction

4. [tex]$Fe(NO_3)_2 \text{ and}\ \ Na_2CO_3$[/tex]

   [tex]$Fe^{2+}(aq)+2NO_3^-(aq)+2Na^+(aq)+CO_3^{2-}(aq) \rightarrow FeCO_3(s) + 2Na^+(aq) + 2NO_3^-(aq)[/tex]5. [tex]$Fe(NO_3)_2 \text{ and}\ \ Na_2CO_3$[/tex]

 [tex]$Fe^{2+}(aq)+2NO_3^-(aq)+2Na^+(aq)+CO_3^{2-}(aq) \rightarrow FeCO_3(s) + 2Na^+(aq) + 2NO_3^-(aq)[/tex]6. [tex]$BaCl_2 \text{ and}\ \ KOH$[/tex]

[tex]$Ba^{+2}(aq)+2Cl^-(aq)+2K^+(aq)+2OH^-(aq) \rightarrow Ba(OH)_2(s) + 2K^+(aq) + 2Cl^-(aq)$[/tex]

7. [tex]$BaCl_2 \text{ and}\ \ KOH$[/tex]

[tex]$Ba^{+2}(aq)+2Cl^-(aq)+2K^+(aq)+2OH^-(aq) \rightarrow Ba(OH)_2(s) + 2K^+(aq) + 2Cl^-(aq)$[/tex]

   

Which best describes the total mass of substances before and after a
combustion reaction?
A. The mass is the same because atoms are not created or
destroyed.
B. The mass is greater after the reaction because the number of
atoms increases.
C. The mass is the same because the molecules do not change.
D. The mass is less after the reaction because gases are produced.

Answers

Answer:

B. The mass is greater after the reaction because the number of

atoms increases.

Compute the number of electrons that each lead atom donates, on average, to a bulk piece of lead metal. Room temperature data for lead: The conductivity of lead is 4.90 × 104 1/(Ω·m) The electron mobility of lead is 2.3 cm2/(V·s) The mass density of lead is 11.4 g/cm3 The atomic weight of lead is 207 g/mol

Answers

Answer:

4 electrons/atom

Explanation:

The conductivity of the lead σ = neμ where n = electron density, e = electron charge = 1.602 × 10⁻¹⁹ C and μ =  electron mobility of lead = 2.3 cm²/(V·s) = 2.3 × 10⁻⁴ m²/(V.s)

Making n subject of the formula, we have

n = σ/eμ

Since σ = 4.90 × 10⁶ (Ω·m)⁻¹

Substituting the values of the variables into the equation, we have

n = σ/eμ

n = 4.90 × 10⁶ (Ω·m)⁻¹/(1.602 × 10⁻¹⁹ C × 2.3 × 10⁻⁴ m²/(V.s))

n = 4.90 × 10⁶ (Ω·m)⁻¹/(3.6846 × 10⁻²³ Cm²/(V.s))

n = 1.33 × 10²⁹ electrons/m³

We now find the number of moles of lead present in 1 m³ of lead.

So n' = ρ/M where ρ = density of lead = 11.4 g/cm³ = 11.4 g/cm³ × 10⁶ cm³/m³ = 11.4 × 10⁶ g/m³ and M = atomic weight of lead = 207 g/mol

So, n' = ρ/M

N = 11.4 × 10⁶ g/m³/207 g/mol

n' = 0.0551 × 10⁶ mol/m³

n' = 5.51 × 10⁴ mol/m³

Since n' = N/N' where N = number of atoms of lead in 1 m³ of lead and N = Avogadro's constant = 6.022 × 10²³ mol⁻¹

N = n'N' = 5.51 × 10⁴ mol/m³ × 6.022 × 10²³ mol⁻¹

N = 33.18 × 10²⁷ atoms/m³

N = 3.318 × 10²⁸ atoms/m³

So, the number of electron per atom is N" = n/N

= 1.33 × 10²⁹ electrons/m³ ÷ 3.318 × 10²⁸ atoms/m³

= 0.4 × 10¹ electrons/atom

= 4 electrons/atom

sodium bicarbonate =sodium carbonate + water + carbon dioxide gas

Answers

Answer: NaHCO3 = Na2CO3 + H2O + CO2



Read about reverse osmosis and multistage flash distillation .Then identify at least three advantages and three

disadvantages for each process

Answers

Answer:

Meaning, Advantages & Disadvantages of - Osmosis, Multiflash Distillatiob

Explanation:

Osmosis is movement of solvent (like water) through semi permeable membrane (like living cell) into solution of higher solute concentration.

Advantages - It assists equalising concentration of solute on two sides of membrane. Reverse Osmosis is used for efficient water softening, it is easy to maintain.

Disadvantages - It needs a lot of energy. A lot of pressure is required for deionisation. Water acidity level increases, as minerals get deionised.

Multistage flash distillation refers to desalination water distilling seawater, by flashing water portions in steams in various stages of concurrent heat exchangers.

Advantages - Its Cost efficient , distillation uses waste heat. It has High gain output ratio. Quality of feedwater is less significant, compared to reverse osmosis.

Disadvantages - It has high operating cost in case of waste heat unavailability. High temperature imply high corrosion & scale formation.

A cylindrical rod of copper (E = 110 GPa) having a yield strength of 240 MPa is to be subjected
to a load of 6660 N. If the length of the rod is 380 mm, what must be the diameter to allow an
elongation of 0.50 mm?

Answers

Answer:

required diameter is 7.65 mm

Explanation:

Given the data in the question;

F = 6660 N

l₀ = 380 mm = 0.38 m

E = 110 GPa = 110 × 10⁹ N/m²

Δl = 0.50 mm = 0.0005 m

So, lets assume the deformation is elastic;

d₀ = √(  [4l₀F] / [πEΔl] )

we substitute

d₀ = √(  [4 × 0.38 × 6660] / [π × (110 × 10⁹) × 0.0005]] )

d₀ = √( 10123.2 / 172787595.947 )

d₀ = √( 5.85875 × 10⁻⁵ )

d₀ = 0.007654 m

d₀ = ( 0.007654 × 1000 )mm

d₀ = 7.65 mm

Therefore, required diameter is 7.65 mm

Carbon-14 has a half-life of 5,730 years. It is used in "carbon dating" to determine the age of once living organisms. How much of a 144 gram sample of C-14 will remain after 17,190 years have past.

Answers

Answer:

18 grams

Explanation:

Because 17,190 yrs divided by the amount of years it takes for a half-life to occur is 3. So 3 half life’s happen, so you divide 144/2 once, equaling 72. You divide 72/2 again (another half-life) and you get 36. You then calculate the third half life by dividing 36/2 which equals 18 grams.

Answer:

5730

Explanation:

Answer to Founders Education:)

A helium-filled balloon contains 0.16 mol He at 101 kPa and a temperature of 23°C. What is
the volume of the gas in the balloon?

Answers

V = 3.9 L

Explanation:

Given:

T = 23°C + 273 = 296K

n = 0.16 mol He

P = 101 kPa = 0.997 atm

R = universal gas constant = 0.08205 L-atm/mol-K

V = ?

Using the ideal gas law,

PV = nRT

V = nRT/P

= (0.16 mil He)(0.08205 L-atm/mol-K)(296K)/(0.997 atm)

= 3.9 L

If an alkene is protonated and the solvent is an alcohol rather than water, a reaction takes place that is very similar to acid-catalyzed hydration, but in the second step of the mechanism the alcohol functions as a nucleophile instead of water. Draw a plausible mechanism for the following process: What is the most likely sequence of steps in the mechanism

Answers

Answer:

Please find the structure of the mechanism in the attached file.

Explanation:

PLEASE HURRY IM TIMED I WILL GIVE BRAINYST (if correct)
What is typical of a grassland? (Select all that apply.)
many trees
grass
wide, open areas
lakes

Answers

Answer:grass and wide open areas

Explanation: grassland- large open area of country covered with grass, especially one used for grazing.

Answer:

i needed the answer to this one too

Explanation:

identify the four quantum number for 3p5​

Answers

Answer:

Four quantum numbers of unpaired electron of chlorine are n=3,l=1,m=0,s=+1/2.

Explanation:

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