At 298 K and 1 atm which noble gas has the lowest density? Why?

1) Ne

2) Kr

3) Xe

4) Rn

Answer:

Yes.

General Formulas and Concepts:

Chemistry - Stoichiometry

Explanation:

Step 1: RxN

Zn + HCl → ZnCl₂ + H₂

Step 2: Balance RxN

Zn + 2HCl → ZnCl₂ + H₂

Answer:

a

Explanation:

Answer:

no one additions exceed the capacity of the buffer

Explanation:

given

Volume buffer = 500.0 mL = 0.5 L

mol HNO₂ = 0.5 L × 0.100 mol/L = 0.05 mol HNO₂

mol NO₂⁻ = 0.5 L × 0.150 mol/L = 0.075 mol NO₂⁻

solution

we know when any base more than 0.05 (HNO2) than exceed buffer capacity

and when any base more than 0.075 (KNO2) than exceed buffer capacity

when we add 250 mg NaOH (0.250 g)

than molar mass NaOH =40 g/mol

and mol NaOH = 0.250 g ÷ 40g/mol

mol NaOH  = 0.00625 mol

0.00625 mol NaOH will be neutralized by 0.00625 mol HNO₂

so it would not exceed the capacity of the buffer.

and

when we add 350 mg KOH (0.350 g)

than molar mass KOH =56.10 g

and mol KOH = 0.350 g ÷ 56.10 g/mol

mol KOH = 0.0062 mol

here also capacity of the buffer will not be exceeded

and

now we  add 1.25 g HBr

than molar mass HBr = 80.91 g/mol

and mol HBr = 1.25 g  ÷ 80.91 g/mol

mol HBr = 0.015 mol

0.015 mol Hbr will neutralize 0.015 mol NO₂⁻  

so the capacity will not be exceeded.

and

we add 1.35 g HI  

molar mass HI = 127.91 g/mol

so mol HI = 1.35 g ÷ 127.91 g/mol

mol HI = 0.011 mol

capacity of the buffer will not be exceed

Answer:

Can you give me your snap, so I can send you the foto

32 days

General formulas used in decay:  

[tex]\large{\boxed{\bold{N_t=N_0(\dfrac{1}{2})^{t/t\frac{1}{2} }}}[/tex]

t = duration of decay  

t 1/2 = half-life  

N₀ = the number of initial radioactive atoms  

Nt = the number of radioactive atoms left after decaying during T time  

The half-life of iodine-131 is 8 days

No=80 g

Nt=5 g

[tex]\tt 5=80(\dfrac{1}{2})^{t/8}\\\\\dfrac{5}{80}=\dfrac{1}{2}^{t/8}\\\\\dfrac{1}{2}^4=\dfrac{1}{2}^{t/8}\\\\4=\dfrac{t}{8}\rightarrow 32~days[/tex]

Answer:

Carbon

Explanation:

Bc i got this question on my test

Answer:

A. Carbon dating

Explanation:

I took the test proof

Answer:

Cs,Ba, Bi

Explanation:

Ionization energy increases across the period from left to right on the periodic table

Answer:

compound

Explanation:

Answer:

The answer is compound

Explanation:

Answer:

Increases

Explanation:

The gravitational potential energy of an object increases as you bring it higher with respect to the ground.

Gravitational potential energy depends on the mass, height and gravity between two bodies;

   Gravitational potential energy  = mgh

m is the mass

g is the height

h is the height

Answer:

19 electrons

Explanation:

Answer:

They have one overall charge

Explanation:

Negative or positive

Answer:

It will remain the same

Explanation:

The equilibrium constant of the reaction will remain the same if the concentration of the OH is increased.

Changes in concentration values of any of the reactant does not affect the value of the equilibrium constant.

The equilibrium constant if the concentration of OH − increases through the addition of a small amount of NaOH(aq) is :

- Remains same.

The equilibrium constant of the response will stay the same in case the concentration of the OH is increased.

Changes in concentration values of any of the reactant does not influence the esteem of the equilibrium constant.

The equilibrium constant may be a consistent at a given temperature.

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Answer: pH = 10

Explanation: First solve for pOH using the equation pOH=-log[OH-] = 4

Then plug the pOH in the equation, pH + pOH =14

then solve for pH. pH =14 - 4 = 10

Answer:

pH= 10

Explanation:

The pH really depends on what your solution is.

For example, if we are assuming that the concentration of 1.0M is of a strong monoprotic acid e.g. HCl, it would be safe to assume that almost all of the 1.0M acid has dissociated into its H+ ion, and its conjugate base. Thus, the pH can be determined by taking the negative log(to base 10), of the concentration.

Inversely, if the solution is of a strong base, the pOH value would be found, assuming the steps above. This pOH value can be used to infer a pH from the formula - pH + pOH = 14 then 14 - 4 = 10

Finally, come the weak acids/bases, which follow the rules above, except as they only partially dissociate, one needs its equilibrium constant to determine its extent of ionisation, to substitute into the negative log. This also is the case for the second, and higher order dissociation of polyprotic acids e.g. H2SO4.the answer is 10

Hope it helps

Answer:

3.85E-12

Explanation:

from

KW=[H3O+]×[OH]

BUT KW=1E-14

Answer:

Seismic waves are the waves of energy caused by the sudden breaking of rock within the earth or an explosion. They are the energy that travels through the earth and is recorded on seismographs. ... Earthquakes radiate seismic energy as both body and surface waves.

Answer:

they are caused from earthquakes

Explanation:

Earthquakes and underground explosions can release a lot of energy. That energy ripples away from its source in a variety of ways. Some of those vibrations will move forward  and back through the material they travel through . Other waves travel just like ocean waves, where they make the material they pass through move up and down compared to the direction the wave is traveling. And while some of these waves travel deep within the planet, still others move only along the surface. Studying where these various flavors of waves are and how they move not only can help scientists pinpoint where an earthquake or explosion occurred, but also can shed light on the structure of our inner planet.

Answer: C

Explanation:

No matter the location on Earth, the sun always rises in the east due to its rotation pattern.

Answer:

Alienus

Explanation:

Answer:

Partial pressure of H₂ →  149.9 atm

Partial pressure of Br₂ → 117.2 atm

Partial pressure of HBr → 112.8 atm

Explanation:

The problem can be solved by the Ideal Gases Law.

In a mixture of gases we know that the sum of partial pressures values the total pressure in the vessel. And the total pressure in the vessel is generated by the total moles which are presennt.

Total moles = 0.954 moles + 1.22 moles + 1 mol = 3.174 moles

Let's apply the Law to determine the total pressure.

P . 1 L = 3.174 moles . 0.082 . 1500 K

P = 390.4 atm

Now we apply the mole fraction concept

Mole fraction (1) →  moles of gas / total moles

Mole fraction (2) → partial pressure of gas / total pressure

In conclussion 1 = 2

Partial pressure of H₂ →  (1.22 / 3.174) . 390.4 atm = 149.9 atm

Partial pressure of Br₂ → (0.954 / 3.174) . 390.4 atm = 117.2 atm

Partial pressure of HBr → (1 / 3.174) . 390.4 atm = 112.8 atm

Answer:

water is a water, but is also known as water. water means water, and the synonym of water is water, and antonym of water is non-water. water is located in earth. water's friends are pure water, salt water, dirty water and ice water. water's best friend is pure water, because when water gives water to pure water, pure water uses the water and gives back the water to the water.

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Explanation:

Answer:

A. 2 Fe, 3 S and 12 O

B. 43 moles of H

C. 1.0×10² moles of C

Explanation:

A. Formula for iron (III) sulfate is Fe₂(SO₄)₃

This salt has 2 atoms of iron and 3 sulfates, so in total we have:

2 Fe, 3 S and 12 O

Pay attention to the subscripts

B. Formula for quinine is: C₂₀H₂₄N₂O₂

If we continue with the example before we can say that 1 mol of Iron (III) sulfate contains 2 moles of Fe, 3 moles of S and 12 moles of O

Then, 1 mol of quinine contains 24 moles of H

So 1.8 moles of quinine, may contain (1.8 . 24) /1 = 43 moles of H

C.  1 mol of quinine contains 20 moles of C

5.4 moles of quinine may contain (5.4 . 20) /1 = 1.0×10²

(As the answer must be in 2 significant figures and the real answer is 108, I had to use scientific notation)

Answer:

If the atom is nuetral it will have 25 electrons as there is the same number of electrons and protons if the atom is nuetral. Yes electrons do orbit the nucleas. Electrons orbit in orbitals which have corresponding energy levels.

Explanation:

I have a masters in Algebra II

Answer:

A

Explanation:

Answer:

I think it's C

Explanation:

Sorry if its wrong

Answer:

C

Explanation:

J.J. Thomson's plum pudding model of the atom followed the discovery of negatively charged particles with a very small mass. Thus, the correct option for this question is A.

J.J. Thomson was a British physicist who discovered sub-atomic particles known as electrons within an atom. He also announced that atoms are made up of smaller components.

The plum pudding model is defined by Thomson in order to demonstrate that negatively charged sub-atomic particles known as electrons are surrounded by a volume of positively charged particles known as protons. It is one of the historical scientific model of the atom that governs all sorts of properties of sub-atomic particles.

Therefore, "negatively charged particles with a very small mass" is the discovery that follows J.J. Thomson's plum pudding model of the atom. Thus, the correct option for this question is A.

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Answer:

percentage yield = 67%

Explanation:

Mass of Cu(NO₃)₂  = 15.25 g

Mass of NaOH   = 12.75 g

Percentage yield = ?

Solution:

Cu(NO₃)₂ + 2NaOH   →  Cu(OH)₂ + 2NaNO₃

Moles of Cu(NO₃)₂:

Number of moles = mass/ molar mass

Number of moles = 15.25 g /187.56 g/mol

Number of moles = 0.08 mol

Moles of NaOH :

Number of moles = mass/ molar mass

Number of moles = 12.75 g / 40 g/mol

Number of moles = 0.32 mol

Now we will compare the moles of Cu(OH)₂ with NaOH and Cu(NO₃)₂.      NaOH             :      Cu(OH)₂

                               2                   :          1

                               0.32              :           1/2×0.32 = 0.16 mol

                            Cu(NO₃)₂         :           Cu(OH)₂

                                  1                  :               1

                             0.08                :              0.08

The number of moles produced by  Cu(NO₃)₂  are less so it will limiting reactant.

Mass of Cu(OH)₂:

Mass = number of moles × molar mass

Mass = 0.08 mol × 97.6 g/mol

Mass = 7.808 g

Theoretical yield = 7.808 g

Percent yield:

percentage yield = Actual yield/ theoretical yield ×  100

percentage yield = 5.23 g/  7.808 g ×  100

percentage yield = 0.67 ×  100

percentage yield = 67%

1.3 grams of copper (II) hydroxide can be prepared from 2.4 grams of copper (II) nitrate (Cu(NO₃)₂) and excess sodium hydroxide.

Let's consider the following balanced double displacement reaction.

Cu(NO₃)₂ + 2 NaOH ⇒ Cu(OH)₂ + 2 NaNO₃

2.4 g of Cu(NO₃)₂ (molar mass 187.56 g/mol) react. The reacting moles of Cu(NO₃)₂ are:

[tex]2.4 g \times \frac{1mol}{187.56g} = 0.013 mol[/tex]

The molar ratio of Cu(NO₃)₂ to Cu(OH)₂ is 1:1. The moles of Cu(OH)₂ produced from 0.013 moles of Cu(OH)₂ are:

[tex]0.013molCu(NO_3)_2 \times \frac{1molCu(OH)_2}{1molCu(NO_3)_2} = 0.013 molCu(OH)_2[/tex]

The molar mass of Cu(OH)₂ is 97.56 g/mol. The mass corresponding to 0.013 moles of Cu(OH)₂ is:

[tex]0.013 mol \times \frac{97.56g}{mol} = 1.3 g[/tex]

1.3 grams of copper (II) hydroxide can be prepared from 2.4 grams of copper (II) nitrate (Cu(NO₃)₂) and excess sodium hydroxide.

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Answer:

Adenosine triphosphate

In science, ATP stands for adenosine triphosphate. This chemical, discovered in the 1920s, is important to all life. It stores and releases energy for many cellular processes. It is found in mitochondria.

Explanation:

Answer:

B?\

Explanation:

A goal of environmentalists is the protection of the environment.

Environmentalist preserve the air and water; as well as conserve and protect entire ecosystems compromising of animals, plants and humans found in different habitats throughout our planet.

Environmentalists help the public make informed decisions about the use of limited natural resources. They do research, produce reports, write articles, campaign etc.

Hence, option b is the correct answer.

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Answer:

two of the above

Explanation:

cK-12 Bond Polarity