Answer:
The excess energy over that needed for dissociation is 3.712 × 10⁻¹⁹ J
Explanation:
Given the data in the question;
wavelength of proton λ = 231 nm = 231 × 10⁻⁹ m
we determine the energy of the proton;
E = hc / λ
where h is plank constant ( 6.626 × 10⁻³⁴ JS )
and c is the speed of light ( 3 × 10⁸ m/s )
we substitute
E = [ ( 6.626 × 10⁻³⁴ JS ) × ( 3 × 10⁸ m/s ) ] / [ 231 × 10⁻⁹ m ]
E = 8.61 × 10⁻¹⁹ J
we know that, bond energy for H-I is 295 kJ/mol
so, H = 295 × 10³ J/mol
Now, energy to dissociate HI will be;
⇒ H / N
where N is the Avogadro's number ( 6.023 × 10²³ mol⁻¹ )
energy to dissociate HI = ( 295 × 10³ J/mol ) / ( 6.023 × 10²³ mol⁻¹ )
= 4.898 × 10⁻¹⁹ J
Therefore, Excess energy over dissociation will be;
⇒ ( 8.61 × 10⁻¹⁹ J ) - ( 4.898 × 10⁻¹⁹ J )
= 3.712 × 10⁻¹⁹ J
The excess energy over that needed for dissociation is 3.712 × 10⁻¹⁹ J
A chemist performs the following reaction:
PCl5 (aq) + 4H2O (l) ⟶ H3PO4 (aq) + 5HCl (aq)
If she has 26.4 g of PCl5, what mass of water should she react to use up all of the
PCl5?
Looking for an in-depth step by step, please
Answer:
9.17 g
Explanation:
1) Calculate mols of PCl5
PCl5 (aq) + 4H2O (l) ⟶ H3PO4 (aq) + 5HCl (aq)
Mass of PCl5: 26.5g
Molar Mass of PCl5 208.24g/mol
Mol of PCl5 = Mass PCl5 /Molar mass PCl5 = 26.5g / (208.24g/mol) = 0.127257011 mol
2) Calculate mols of water needed to react
Mols of H2O per 1 Mols of PCl5 = 4 (because 4 water is needed to Phosphorus pentachloride).
Mols of H2O = Mol of PCl5 * 4 = 0.127257011 * 4 = 0.509028044 mols
3) Calculate Grams of water needed to react
Mols of H2O = 0.509028044 mols
Molar Mass of H2O = 18.015 g/mol
Mass of H2O = Mols of H2O * Molar Mass of H2O
= 0.509028044 mols* 18.015 g/mol = 9.17014021 g
sf = 3
9.17 g
what takes place when the pollen grains are transferred to the stigma of the same flower with the help of pollinators
Answer:
self-pollination.
Explanation:
When the pollen of the flower is transferred to the stigma of the same flower, it is called self-pollination. Cross-pollination occurs when pollen is transferred from one flower to another flower on the same plant, or another plant.
need help with this question, anybody ..
-20 points :)
Which is better Epoxy or Super Glue?
Answer:
Personally, I use Superglue
Explanation:
please help me!! DUE TOMORROW :(
Answer:
It’s in the photo, sorry if it’s really messy!
Explanation:
Please ask if you have any questions!
NEED ASAP THANK YOU!
Answer:
d. 10
Explanation:
The 24 means the atomic mass and twelve means the number of electrons. You subtract the number of electrons from the atomic mass. 24-12=12
Then, since there's +2, you subtract 2 from 12 which equals 10 which means there are 10 electrons now.
The confusing thing is that + means subtract and - means add here.
Hope this helps.
1. Before starting, make a prediction: If substances B and C are both in the gas phase and are at the same energy level, which of the two substances will need to have more energy transferred out in order to change to the liquid phase? Substance B or substance C? Explain your answer.
Answer:
Substance C
Explanation:
Substance C would be the answer because Substance C has a lower attraction level. Because of this, it takes more energy to take out of in order to become a liquid.
Which one of the following statements about balanced is true? A reaction is balanced by
why compounds with weak molecular forces are usually gases.
Molecular substances tend to be gases because the intermolecular forces of attraction are comparatively weak. You don't have to break any covalent bonds in order to melt or boil a molecular substance.
The longest intermolecular separation and hence the strongest intermolecular pressure of attraction can be found in the gaseous state of matter.
Although solids' intermolecular interactions were sufficient to maintain themselves in locked places, gases often have weak intermolecular forces that cause them to remain considerably separated. The gases possess greater intermolecular space than solids as a result of these weak forces.
To know more about molecular forces:
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Which of the following is used for purification of water?
a) Sodium bicarbonate
b) Alum
c) Copper sulphate
d) Sodium Hydroxide
A. Sodium bicarbonate is a water treatment method used to soften water (removing calcium and magnesium impurities from it) in older water softener systems. The process uses a chemical reaction to convert the calcium hydroxide (or magnesium hydroxide) into calcium carbonate, which isn't water soluble.
B. Alum, also known as potassium aluminum sulfate, can be used to purify water. ... Add 1.4 ounces of alum powder to the contaminated water in the reaction vessel and carefully stir the mixture with the stirring stick for at least five minutes. Sediment will form as the phosphorous in the water binds with the alum powder.
C. If Copper sulphate crystals are added to water it is called 'hydrated copper sulphate solution'.
If it is added to cold water then:-
it is more saturated
but if it is added to warm water then:-
it is unsaturated
and it turns bluish in colour in dissolving in water
D. Sodium hydroxide is used in the treatment of drinking water to raise the pH of the water to a level that minimizes the corrosion. Raising the pH remains one of the most effective methods for reducing lead corrosion and minimizing lead levels in drinking water.
9 Select the correct answer. Which statement correctly describes a physical change? O A involves breaking and creating chemical bonds but not changing a phase OB. may involve a change in phase but does not involve a change in the molecular structure OC. may involve converting two or more substances into new substances OD. involves changes at the molecular level O E. involves energy transfer and change in color Reset Next
Answer: The statement that correctly describes a physical change is may involve a change in phase but does not involve a change in the molecular structure. The answer is letter B.
Explanation: trust me
Explanation:
OA- because there is breakdown of chemical bonds
Can someone label these PLEASE !!! HELPPPPPP! DUE TODAYY
Answer:
1. melting
2boiling
3. freezing
4. condesation
Explanation:
What kind of elements form covalent compounds?
Answer:
Covalent bonds usually occur between nonmetals. For example, in water (H2O) each hydrogen (H) and oxygen (O) share a pair of electrons to make a molecule of two hydrogen atoms single bonded to a single oxygen atom. In general, ionic bonds occur between elements that are far apart on the periodic table.
What is epoxy?
....................
Answer:
1. any class of adhesives, plastics, or other materials that are polymers of epoxies.
2. something like glue or resin
Explanation:
that's the dictionary definition of epoxy.
If the adoms dont work are they dead
Answer: no
Explanation:
Atoms are not and have never been alive so they can't be considered dead. they simply do not meet any reasonable of life, primarily because they are not complex.
Explain why the total mass of carbon must be decreasing in a different step of the slow carbon cycle based on the increase in atmospheric CO2.
Total mass of carbon must be decreasing in different step of carbon cycle because matter is conserved in the processes and reactions of carbon cycle. Carbon is a matter and it is the major constituent of living organisms.
Carbon cycle refers to processes where carbon move from the atmosphere to the biosphere and Earth and then back to the atmosphere.
It involves processes of using and reusing carbon again and again and it's conservation.
Carbon is an organic matter found in living organisms and total mass of carbon reduces because it is a matter that is conserved.
Carbon is released from that atmosphere, use for photosynthesis, plants and animals consume the plants. They defecate , respirate and carbondioxide is released during respiration.
Therefore,Total mass of carbon must be decreasing in different step of carbon cycle because because matter is conserved in the processes and reactions of carbon cycle. Carbon is a matter and it is the major constituent of living organisms.
Learn more about Carbon cycle from the link below.
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how many moles of carbonate are there in sodium carbonate
There are 0.566 moles of carbonate in sodium carbonate.
CALCULATE MOLES:The number of moles of carbonate (CO3) in sodium carbonate (Na2CO3) can be calculated by dividing the mass of carbonate in the compound by the molar mass of the compound. no. of moles of CO3 = mass of CO3 ÷ molar mass of Na2CO3Molar mass of Na2CO3 = 23(2) + 12 + 16(3)= 46 + 12 + 48 = 106g/molmass of CO3 = 12 + 48 = 60gno. of moles of CO3 = 60/106 no. of moles of CO3 = 0.566molTherefore, there are 0.566 moles of carbonate in sodium carbonate.Learn more about number of moles at: https://brainly.com/question/1542846
identify a binary salt among the following a,KNO3 b,NACIO3 c,MGSO4 d,CaCL2
The binary salt among the given salts is CaCl₂. The correct option is d,CaCl₂
From the question,
We are to identify the binary salt among the given salts.
First, we will define the term binary salt
A binary salt is a chemical compound that is formed from the mixture of a metal and a non-metal.
Among the given options, CaCl₂ is the salt formed from the mixture of a metal and a non-metal.
The metal is Calcium (Ca)
and the non-metal is Chlorine (Cl)
Hence, the binary salt among the given salts is CaCl₂. The correct option is d,CaCl₂
Learn more here: https://brainly.com/question/3103303
What is the mass percent of nitrogen in:
1. N2O
2. NO
3. NO2
4. N2O2
Question 1
Of the following which displays a positive energetic process?
We can describe a positive energetic process as any process which increases the internal energy of the system.
A positive energetic reaction or process is often referred to as being Endothermic. This means that the system which is performing the process absorbs energy. Some examples include:
Boiling an EggRoasting food over a fire (the food is the reference system)etc
Therefore, we can confirm that a positive energetic process is one in which the system in question absorbs energy, thus increasing its internal energy.
Since I could not locate the options online, I have provided a general explanation of the concept coupled with a few examples.
To learn more visit:
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what is the chemistry of super glue
cyanoacrylate
When cyanoacrylate polymerizes, the cyanoacrylate sticks together on an atomic level, and it becomes solid. Super Glue solidifies in all the microscopic crevices of an object that it moved into when it was a liquid, and it can form chemical bonds with any anions in the object.
how many molecules are in 2.50 moles of co2
Answer:
[tex]1.51 \times 1024 \: \: molecules[/tex]
Explanation:
There are 1.51 x 1024 molecules of carbon dioxide in 2.50 moles of carbon dioxide.
Which branch of Earth science focuses more specifically on Earth's atmosphere?
Answer:
Meteorology
Explanation:
Meteorology focuses on Earth's atmosphere and, especially, how changes in the atmosphere affect weather and climate on Earth's surface.
What law of motion corresponds with this statement?
"A rifle kicks."
first law
third law
second law
Answer:
3rd lawl
Explanation:
a rifle kick is when you fire a projectile and you feel a force pushing against your hand. Rifles normally have heavier projectiles so there is more force pushing back against you. example, if you were sitting on a spinny chair with wheeles and your friend is sitting on another, and you push each other while on the chair, you will both go backward, but the lighter person will go back more. for every action, there is an equal and opposite reaction
that is the third law, also said as: "When one body exerts a force on a second body, the second body simultaneously exerts a force equal in magnitude and opposite in direction on the first body."
Which type of rock is formed when rocks are melted deep in the Earth and cool to form new rocks?
A. Igneous
B. Metamorphic
C. Sandstone
D. Sedimentary
Answer:
igneous
Explanation:
key word: melt, cool. igneous rocks are when lava is melted then cooled off, then becoming a igneous rock.
Which of the following shows the valency of 1?
a) nitrogen
b) carbon
c) oxygen
d) sodium
[tex]\huge \bf༆ Answer ༄[/tex]
The element having valency of 1 is ~
Sodium (Na)Answer: Pretty sure this is d.) sodium
Explanation:
Which method is used to obtain common salt from rock salt? Why?
What is the momentum of a car if its mass 200kg and moving with a speed of 3m/s?
600 kg·m/s
Given:Mass = 200 kg
Velocity = 3 m/s
Power = Mass * Velocity = 200 kg * 3 m/s = 600 kg·m/s
activation energy in reaction is used to:
A- Overcome repulsion force between colliding molecules
B- Breaking bonds
C- Merge Valence electrons
D- All of them
Answer:
D — All of them
Explanation:
The activation energy in a reaction is the minimum amount of energy required for a chemical reaction to take place. Since all the options are processes in a chemical reaction, D should be the answer.
Which of the following is not a place where hydrogen can be found on Earth?
A) Natural gas well
B)
Water
Mine
Atmosphere
Answer:
Atmosphere
Explanation:
Natural gas is mainly hydrocarbons like C3H8 and that has hydrogens, water is H2O and had hydrogens, mines have it in the minerals.
