Answer:
Explanation:
wavelength λ = 12.4 x 10⁻² m .
energy of one photon = h c / λ
= 6.6 x 10⁻³⁴ x 3 x 10⁸ / 12.4 x 10⁻²
= 1.6 x 10⁻²⁴ J .
Let density of coffee be equal to density of water .
mass of coffee = 255 x 1 = 255 g
heat required to heat up coffee = mass x specific heat x rise in temp
= 255 x 4.18 x ( 62-25 )
= 39438.3 J .
No of photons required = heat energy required / energy of one photon
= 39438.3 / 1.6 x 10⁻²⁴
= 24649 x 10²⁴
= 24.65 x 10²⁷ .
when 0.20 m nh4cl (aq) and 0.20 m naoh(aq) are mixed, the reaction represented by the equation above occurs and a strong smell of ammonia, nh3 is observed. based on this information, which of the following statements is true? And Why??
Answer:
b ) NH₄⁺ is a stronger acid than H₂O ( l )
Explanation:
NH₄⁺ + OH⁻ = NH₃ + H₂O .
NH₄⁺ is a conjugate acid of NH₃
OH⁻ is a conjugate base of H₂O .
NH₄⁺ is capable of giving H⁺ to OH⁻ to produce H₂O so it is stronger acid than H₂O .
Had H₂O been stronger , it would have given H⁺ to NH₃ to produce NH₄⁺ but it does not happen .
So NH₄⁺ is a stronger acid than H₂O ( l ) .
Which of the following elements is the best conductor of electricity?
hydrogen
magnesium
carbon
iodine
Answer: carbon
Explanation:
Answer: hydrogen
Explanation: Hydrogen is usually considered an energy carrier, like electricity, as it must be produced from a primary energy source such as solar energy, biomass, electricity (e.g. in the form of solar PV or via wind turbines), or hydrocarbons such as natural gas or coal. On the other hand, magnesium, carbon, and iodine are not often used as conductors of electricity because they either have a covalent bond that does not generate electricity or because they contain particles or compounds that can’t be installed inside electric installations.
How many grams of sodium chloride decompose to yield 15 grams of chlorine gas?
2NaCl → 2Na+ Cl2
A- 12.363 9 Naci
B- 49.453 g Naci
C- 30 g NaCl
D- 0.846 g Naci
Answer:
24.6g of NaCl
Explanation:
Expression of the reaction:
2NaCl → 2Na + Cl₂
Given parameters:
Mass of Cl₂ = 15g
Unknown:
Mass of NaCl = ?
Solution:
To solve this problem, we have to use mole relationships.
Find the number of moles of the mass of the given specie;
Number of moles = [tex]\frac{mass}{molar mass}[/tex]
Molar mass of Cl₂ = 2(35.5) = 71g/mol
Number of moles = [tex]\frac{15}{71}[/tex] = 0.21mole
Now;
From the balanced reaction equation;
1 mole of Cl₂ is produced from 2 moles of NaCl;
0.21 mole of Cl₂ will be produced from 0.21 x 2 = 0.42mole of NaCl
So,
Mass of NaCl = number of moles x molar mass
Molar mass of NaCl = 23 + 35.5 = 58.5g/mol
Mass of NaCl = 0.42 x 58.5 = 24.6g of NaCl
Complete the chemical equation for this reaction.
Ca + .......H2O → Ca(OH)2 + ...............
Please help me due today at 7:00pm please help giving more points please help me
I NEED HELP FAST THIS IS DUE AT 9:00
All atoms of the same ___________ have the same properties
Elements
Compounds
Mixtures
Chemicals
The gravitational pull of the Moon is much less than the gravitational pull of Earth. Consider an object with a ma of 10 kilograms that weighs 22 pounds on Earth Which statement describes the object on the Moon? A. Its mass would be much greater. B. lts weight would be much greater OOOO C. Its we ght would be the same O D. Its mass would be the same.
Answer: D.
Explanation: I got it right and the dude above me is spreading fake news
What is the order of reagents that were added to the test tube used to carry out the synthesis of dibenzalacetone?
Answer:
An experiment designed to synthesize dibenzlacetone would have reagents added in the following order:
Sodium hydroxide, NaOHEthanolAcetoneBenzaldehydeYellow precipitate would be re-crystallized from ethyl acetate.Explanation:
It is worth noting that the reaction is a type of mixed aldol condensation reaction, which uses sodium hydroxide as base.
I hope this is was a clear solution to the problem.
You have a gas at a volume of 9.71 L at a pressure of 209 torr and at 10.1 °C. What
temperature (in °C) would the gas need to reach at constant volume to reach
364 torr? 760 torr = 1 atm
Answer:
219.95 °C
Explanation:
Given data:
Volume of gas = 9.71 L
Initial pressure = 209 torr (209/760 = 0.275 atm)
Initial temperature = 10.1 °C (10.1 +273 = 283.1 K)
Final temperature = ?
Final pressure = 364 torr (364/760 =0.479 atm)
Solution:
According to Gay-Lussac Law,
The pressure of given amount of a gas is directly proportional to its temperature at constant volume and number of moles.
Mathematical relationship:
P₁/T₁ = P₂/T₂
Now we will put the values in formula:
0.275 atm / 283.1 K = 0.479 atm/T₂
T₂ = 0.479 atm × 283.1 K/ 0.275 atm
T₂ = 135.6 atm. K /0.275 atm
T₂ = 493.1 K
Kelvin to °C:
493.1 K - 273.15 = 219.95 °C
How might emission spectra be used in studying stars?
Answer:
Emission spectra may be used in studying stars in order to determine what atoms makeup the individual star produces, due to the fact that each atom’s emission spectra biunique, one can observe the spectra emitted by the star and identify the atoms that are released by the light the star produces.
The emission spectrum can tell the elements present in the source of light. Therefore, this method can be used to get information about the element present in the stars.
What is the emission spectrum?Electromagnetic radiations interact with atoms or molecules of matter, the electrons absorb energy and jump to a higher energy state of atoms by losing their stability.
They need to move from the higher energy state to the lower energy level to regain their stability. These atoms or molecules emit radiations in several regions of the electromagnetic spectrum. The spectrum of radiation emitted by electrons in the excited state is called the emission spectrum.
The emission spectrum of a chemical element is the spectrum of frequencies of electromagnetic radiation emitted when an atom transitions from a high-energy state to a lower-energy state. The emitted energy is unique for every element and is the characteristic of the element.
Learn more about the emission spectrum, here:
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which of these is NOT an example of an inclined plane?
A. Ladder
B. Stairs
C. Wall
D. Driveway
Answer:
I think its D
Explanation:
It doesn't go straight up
It is the one in the middle i listened to the first person and i got it wrong by the way this is the answer for edge2020 sience review
Answer:
for what school? It's different for all sadly :(
Explanation:
please help...
3. Which substance will take more energy to heat from 20C to 100C?
a) 30 g of water
b) 300 g of water
WHY?
please explaining why.....
Answer:
a because it comes 20 to 100c
If you have a metal oxide and water in a combination reaction, what will the product be?
a
Acid
b
Molecular
с
Carbon Dioxide
d
Base
Answer:
A
Explanation:
A
is often written as an if/then statement.
O prediction
O law
O theory
O guess
Which element has properties similar to neon?
A. Aluminum
B. Argon
C. Arsenic
D. Silver
Answer:
B. Argon has similar properties to neon.
Explanation:
hope it helps u.
The statement of element has properties similar to neon is "argon."
What is an element?A substance that cannot be split into smaller components using normal chemical processes. Elements are chemical compounds that correspond to a single spot on the current periodic table. Elements are made up of only one type of atom.
Argon, like neon, is classified as a noble gas. That is, argon is a member of the noble gas family of chemicals.
Both neon and argon are positioned in the group 8, which means they have eight electrons in their outermost electron shell, making them noble and inert gases. They are very nonreactive since they already have a complete and stable octet structure and don't need to connect to other elements.
Hence the correct option is B.
Learn more about element here
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Please it’s due today at 6:00pm please help me will mark the brainiest and more points please help me
Answer:
A SUV their more dynamic if u say so (Dads a car person) But he could be wrong
What is chemical potential energy?
A) energy stored by atoms
B) energy from gravity
C) energy of motion
D) energy stored in height differences
Answer:
A) energy stored by atoms
Explanation:
Chemical potential energy is the energy stored by atoms. This energy form can be converted to other forms of energy.
For most of the energy needs in the biosphere, this form of energy is very important. When bonds are broken, this energy is released as it is converted to other forms of energy. The food we eat contains chemical potential energy within its structure.How could you draw a model of the element copper to show that it is different from the element gold?
please help me hope you understand helllllllpppppppppppppppppp meeeeeeeeee
Answer:
You can put what they are made out of so show how different they are
Which of the following phrases helps you to correctly remember the order of classification levels?
A) Kings cut pickles on fat green stools.
B) Kings played cards for one great second.
C) Kings play cards on fat green stools.
D) Kings cart plums for Greeks on stools.
ОООО
Answer: The correct answer would be C.
Explanation: The order of classifications are kingdom, phylum, class, order, family, genus, and species. :)
Answer B
Explanation:Which of the following phrases helps you to correctly remember the order of classifition levels?
the answer is B
PLEASEEE HELPPP!!!!!!
Two students were conducting and experiment based on the ionization energy of alkali metals. The driving question for the experiment was: "What is the relationship between ionization energy and the rate of reaction (time for the reaction to be completed) using alkali metals."
Which of the following predictions would be the best option based on the student's prior knowledge learned and information provided in the graph above?
A.
Cesium will have a higher rate of reaction (faster) because it has the lowest ionization energy which indicates a higher reactivity.
B.
Cesium will have a lower rate of reaction (slower) because it has the lowest ionization energy which indicates a lower reactivity.
C.
The ionization energy of the alkali metals will not affect the rate of the reaction because the energy required to remove an electron does not affect time.
D.
Lithium will have a higher rate of reaction (faster) because it has the highest ionization energy which indicates a higher reactivity.
Answer:
A
Explanation:
Cs has a higher rate of reaction because it's easier to remove an electron from it, thereby leading to faster reactivity
Answer:
It's A but can i have brainliest pls i kinda need it
Explanation:
The ΔHvap of a certain compound is 47.45 kJ·mol−1 and its ΔSvap is 59.15 J·mol−1·K−1. What is the boiling point of this compound?
Answer:
802.2 K
Explanation:
To solve this problem we can use the formula:
Tb = ΔHvap / ΔSvapWhere Tb is the boiling point (in K).
We already know the values of both ΔHvap and ΔSvap, so we calculate Tb:
ΔHvap = 47.45 kJ·mol⁻¹ = 47.45x10³J·mol⁻¹Tb = 47.45x10³J·mol⁻¹/59.15 J·mol⁻¹·K⁻¹
Tb = 802.2 KSo the boiling point of the compound is 802.2 K (or 529 °C)
The boiling point of the compound whose ΔHvap is 47.45 KJ is 802.2 K.
What is the boiling point?The temperature at which a liquid's vapor pressure matches the pressure surrounding the liquid is known as the boiling point of that substance.
By the formula of colligative property
[tex]Tb = \dfrac{\Delta Hvap}{\Delta Svap }[/tex]
Where Tb is the boiling point (in K).
ΔHvap is 47.45 kJ·mol⁻¹
ΔSvap is J·mol−1·K⁻¹
Putting the values
[tex]Tb = \dfrac{47.45}{59.15 } =802.2 K.[/tex]
Thus, the boiling point is 802.2 K or 529° C.
Learn more about boiling point
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Give the name for the ionic compound NiN
Answer: potassium chloride
True or False.
E = mc2 explains why a small amount of mass can produce a great deal of energy.
The data part of Lab Hydrates in Edgunuity
Answer:
Hydrates! :D
Explanation:
Do covalent bonds form in order to fulfill the octet rule
Answer:
YES
Explanation:
the main reason why bonds form is because the elements wants to be more stable so in a covalent bond the electrons are shared between two elements so they can fulfill or at least "feel" like they have fulfilled there outer shell.
difference between elimination and substitution
Answer:
elimination:it is the act of discharging or excreting waste product from body is elimination.
substitution:the act/action of replacing someone or something with another person or thing.
Which is the transfer of thermal energy through direct contact of particles?
A.radiation
B.specific heat
C.conduction
D.convection
Explanation:
conducting goodnluck
Answer:
C. Conduction
Explanation:
direct contact of particles will always be conduction.
an experiment should be carried out in the fume cupboard if it involves
Answer:
if you are working with a substances that produce or generate toxic or harmful fumes, vapours, gases, dust or chemical aerosols
it should be carried out in a fume cupboard to eliminate or reduce the risk of exposure to an acceptable and safe level.
I need help with this question!!!
Answer:
its c
Explanation: