The work function is 4.74eV if light frequency [tex]1.40 X 10^{15}[/tex] Hz strike a surface causing photoelectrons to leave with a KE of 1.05 eV.
What are photoelectrons?When light whose frequency is more than the threshold frequency incident on the metal, electrons are emitted. Such electrons are called photoelectrons.
The photoelectric effect is a phenomenon in which a beam of light is projected towards a metal plate and this leads to the ejection of electrons from the metal. The minimum amount of energy required for this ejection of electrons is known as the work function. When the energy of the light beam is less than the work function, then the electrons are not emitted.
The photoelectric effect is represented by the equation:
E = φ + KE where
E = energy of the incident photons
KE = kinetic energy of photoelectrons
φ = Work function of the metal
This can also be written in terms of frequency as:
h = h₀ + [tex]\frac{1}{2}[/tex]mv²
h₀= frequency of the incident light beam
m = mass of the electron
v = velocity of the electron
h = Plank's constant 6.623 x 10⁻³⁴Js
Conversion factor: 1eV = 1.602 x 10⁻¹⁹ J
So, 1.05eV = 1.682 10⁻¹⁹ J
Using the formulas,
(6.623 x 10⁻³⁴Js)(1.40x10¹⁵ s⁻¹) = φ + 1.682 x 10⁻¹⁹ J
(9.272 x 10⁻¹⁹) - (1.682 x 10⁻¹⁹) = φ
φ = 7.590 x 10⁻¹⁹ J = 4.74 eV
Hence, the work function is 4.74eV if light frequency 1.40x10^15 Hz strike a surface causing photoelectrons to leave with a KE of 1.05 eV.
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What is the first step in the scientific process?
O develop a test
O make a prediction about what may be happening
O observe a natural phenomenon
O generate a scientific hypothesis
O check results by repeating work
[tex]\quad \huge \quad \quad \boxed{ \tt \:Answer }[/tex]
[tex]\qquad \texttt {Observe a natural phenomenon}[/tex]
____________________________________
[tex] \large \tt Explanation \: : [/tex]
At first scientists/researchers observe a natural phenomenon. after enough observation, they make predictions why that phenomenon is happening and the reasons that lead to that particular phenomenon. then they generate scientific hypothesis to explain that phenomenon and after getting enough data they develop tests and perform experiments. And check the results they get and at last based on the results they conclude what actually is happening.
Answered by : ❝ AǫᴜᴀWɪᴢ ❞
describe how molecular motion and distance between molecules change as ice is heated to become a liquid and the gas
The conversion of heat to kinetic energy inside the water molecules causes the motion of the molecules to increase. The distance between molecules widens when the molecules move more quickly and clash more frequently. (As more heat is absorbed, the distance between molecules for solids, liquids, and gases widens)
The average atomic mass of carbon is 12.01 amu. Based on the atomic
masses of the two isotopes of carbon, how do the relative abundances of the
isotopes compare?
Isotope
Atomic mass (amu)
C-12
12.000
C-13
13.003
OA. There is a slightly larger percentage of C-12 than C-13.
OB. There is a very large percentage of C-12.
OC. There is a very small percentage of C-12.
OD. They are about the same.
Answer: There is a very large percentage of C-12.
Explanation:
The atomic mass is must closer to that of C-12 than of C-13, meaning that there is a much larger percentage of C-12.
The temperature of a 0.85kg block of copper was found to be 21 degrees the copper was placed in the sun and temperature increased to 28 degrees.Assume the specific heat of copper to be 0.385J/g degrees and determine the amount of heat absorbed by the block of copper.
Answer:
2290 . 75 J absorbed
Explanation:
The copper changed from 21 to 28 degrees= 7 degrees
.85 kg = 850 gm
850 gm * 7 degrees * .385 J / g-degree) = 2290.75 j
Aryan want to deposit silver on an iron spoon using silver nitrate as electrolyte. Which terminal of the battery he should connect the spoon? What material should the other electrode be made of?
Silver from the anode gets dissolved to reach the cathode, where the spoon will be plated.
What is electroplating?Electroplating is a way of electrolysis, where a thin layer of metal is used to plate a determined object. It is a kinda process to purify a material you want.
The anode contains the metal you want to plate with, in this case, the Ag.
The anode contains the half-reaction of oxidation so:
Ag(s) → Ag ⁺ (aq) + e⁻
In the cathode, you have the spoon, which it takes place the half-reaction of reduction:
Ag ⁺ (aq) + e⁻ → Ag(s)
The electrolytic cell, where the redox reaction takes place, must be filled with a AgNO₃ solution.
Silver from the anode gets dissolved to reach the cathode, where the spoon will be plated.
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PLEASE NO FAKE ANSWERS!! Chemistry!!! Please will give brainliest !! Show work
When 1 mole of Zn and 2 mole of O₂ reacts togethor, It will produce 1 mole of ZnO as O₂ is excess reagent and Zn will act as Limiting reagent and thus it limits the amount of product formed.
What is Limiting reagent ?Limiting reagents are the substances that are completely consumed first in a chemical reaction.
Given ;
Amopunt of Zn : 1 moleAmount of O₂ : 2 moleGiven equation ;
2Zn + O₂ --> 2ZnO
As according to given chemical equation,
2 moles Zn of reacts with 1 mole of O₂ to produce 2 moles of ZnO.
Therefore,
1 mole of Zn will require 0.5 mole of O₂.
But,
the given amount of O₂ is 2 mole which is excess
Hence,
Zn here will act as the Limiting reagent, According to which the amount of product formed will be decided.
Therefore,
If 2 mole Zn produces : 2 moles of ZnO (According to given balanced equation)
Thus,
1 mole of Zn will produce = 2/2 x 1
= 1 mole of ZnO
Hence, When 1 mole of Zn and 2 mole of O₂ reacts togethor, It will produce 1 mole of ZnO as O₂ is excess reagent and Zn will act as Limiting reagent and thus it limits the amount of product formed.
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-You wish to make a 0.203 M hydrochloric acid solution from a stock solution of 6.00 M hydrochloric acid. How much concentrated acid must you add to obtain a total volume of 175 mL of the dilute solution?
mL
-In the laboratory, a student dilutes 20.3 mL of a 8.20 M hydrochloric acid solution to a total volume of 200.0 mL. What is the concentration of the diluted solution?
Concentration =
M
-How many milliliters of 9.36 M perchloric acid solution should be used to prepare 1.50 L of 0.700 M ?
mL
For all three questions, we will use the fact that
molarity = (moles of solute)/(liters of solution)1) For 175 mL of solution at 0.203 M, this means that:
0.203 = (moles of solute)/0.175moles of solute = 0.035523 molConsidering the hydrochloric acid solution, if we have 0.035523 mol, then:
6.00 = 0.035523/(liters of solution)liters of solution = 0.035523/6.00 = 0.0059205 = 5.92 mL (to 3 sf)2) If there is 20.3 mL = 0.0203 L, then:
8.20 = (moles of solute)/0.0203moles of solute = 0.16646 molThis means that the molarity of the diluted solution is:
0.16646/(0.200) = 0.832 M (to 3 sf)3) If we need 1.50 L of 0.700 M solution, then:
0.700 = (moles of solute)/1.50moles of solute = 1.05 molConsidering the 9.36 M acid solution, from which we need 1.05 mol of perchloric acid from,
9.36 = 1.05/(liters of solution)liters of solution = 1.05/9.36, which is 0.11217948717949 L, or 112 mL (to 3 sf)Indicate the number of significant figures in the following measured numbers:
a. 45 = __________
f. 980.00 = __________
b. 450 = __________
g. 740000 = __________
c. 0.0045 = __________
h. 0.00000042 = __________
d. 3006 = __________
i. 4050600 = __________
e. 0.00780 = __________
j. 230.0050 = __________
Answer: a = 2 ; f = 5 ; b = 2 ; g = 2 ; c = 2 ; h = 2 ; d = 4 ; i = 5 ; e = 3 ; j = 7
Explanation: Some rules to follow while calculating sig figs is
1. If a number like 4500 is present, only two sig figs are counted, but none of the zeros are, but if 4500. has a decimal point present, then you should count all the numbers available.
2. If a number like .0005 is present, only count 5 as a sig fig, however if the number is .00050, count the 0 after the 5 in this example (this would then have two sig figs.
Engineers are starting on a new project to develop technology. Which of these
statements does not describe something they might do at the very beginning
of the process?
OA. Look at the problems society is facing.
OB. Make a decision about how to best apply the technology.
C. Look at the benefits and challenges of using specific materials.
OD. Decide whether they have designed the best possible product.
Answer: Decide whether they have designed the best possible product.
Pb + 02 - Pb304 help
Answer:
6PbO +O2 --> 2Pb3O4
Explanation:
The question is incomplete I assume it is
PbO + 02 - Pb304
How many grams of fluorine are needed to generate 7.65 moles Carbon Tetrafluoride
Answer:
36.3375 g
Explanation:
Using a table of standard electrode potentials, label each of the following statements as completely
true or false.
A) Cu²+ can oxidize H2, and Fe can reduce Mn²+
B) Ni²+ can oxidize Cu²+, and Fe²+ can reduce H+
C) Fe²+ can oxidize H₂, and Fe²+ can reduce Au³+.
D) Br₂ can oxidize Ni, and H₂ can reduce Mn²+
E) H* can oxidize Fe, and Ni can reduce Br₂
Answer: B and E are True
Explanation:
Because Fe has a higher oxidation potential than H2, H+ can oxidize it.
[tex]$\begin{array}{llllll}\mathrm{Fe} & \rightarrow & \mathrm{Fe}^{2+} & +2 \mathrm{e}- & \mathrm{E}^{0}=0.44 \mathrm{~V} \\ \mathrm{H} & \rightarrow & \mathrm{H}^{+} & + & \mathrm{e}^{-} & \mathrm{E}^{0}=0 \mathrm{~V}\end{array}$[/tex]
Ni can reduce Br2 because the reduction potential of Ni is more than Br2.
[tex]\mathrm{Ni}^{2+}+2 \mathrm{e}^{-} \rightarrow \mathrm{Ni}^{-} \quad \mathrm{E}^{0}=-0.25 \mathrm{~V}\\2 \mathrm{Br}^{-} \quad \rightarrow \mathrm{Br}_{2}+2 \mathrm{e}^{-} \quad \mathrm{E}^{0}=-1.087 \mathrm{~V}$[/tex]
Type of chemical reaction of Ca(OH)2.
Answer:
Combination reaction
This reaction is a combination reaction because calcium oxide and water combine to create calcium hydroxide as the only result.
What is Ca(OH)2?An inorganic substance called calcium hydroxide has several uses. It is also known as slaked lime, and limewater is the name of its aqueous solution.
Calcium hydroxide has the chemical formula Ca in both its composition and structure (OH)
2
and it has a 74.09 g/mol molar mass.
The calcium metal cation is linked to two hydroxide anions in this ionic molecule. Calcium hydroxide has a polymeric structure in its solid state, which is made possible by hydrogen bonds between the layers.
The mineral portlandite, a naturally occurring but seldom type of calcium hydroxide, is present in various volcanic and metamorphic rocks.
In order to make calcium hydroxide for use in industry, calcium oxide (lime or quicklime) is reacted with water.
CaO + H
2
O → Ca(OH)
2
On lesser scales, it may also be produced through the reaction of aqueous calcium chloride and sodium hydroxide.
Physical characteristics: It has a melting point of 580 °C and can be found as white powder or colorless crystals with a density of 2.21 g/cm3.
Chemical characteristics: Water may rather easily dissolve calcium hydroxide. It partly dissolves in water to create limewater, a moderately basic solution. Ca(OH)2 solution or limewater
salts when combined with acids, and it can corrode various metals, including aluminum. The process of carbonatation, which produces calcium carbonate from limewater and carbon dioxide, is advantageous:
Ca(OH)2+ CO2→ CaCO3+ H2O
Uses: Calcium hydroxide is used in a wide range of industrial processes, including the production of Kraft paper, water and sewage treatment, the production of ammonia, and pH adjustment. Additionally, it is a crucial component of mortars, cement, and plaster. It may be used in the food business for a variety of purposes, including pH correction, calcium fortification, digestion help, and baking soda replacement because it is a relatively non-toxic and gentle base.
Calcium hydroxide is not poisonous at low doses and poses no safety risks. However, inhaling, eating, or coming into touch with the aqueous calcium hydroxide solution at greater concentrations might result in lung damage, chemical burns, blindness, or serious skin irritation.
Explain the term 'end point'?
What do you mean by a 1.0 M solution?
Answer:
According to me end point is the end of a reaction
Help please!
A new element with atomic number 116 was discovered in 2000. In 2012 it was named livermorium, Lv. Although Lv is radioactive and short-lived, its chemical properties and reactivity should follow periodic trends.
a. Determine the electron configuration for the valence electrons of Lv in the ground state. (2 pts)
b. It has been suggested that Lv can form a 4+ ion. Identify what would be the electron configuration for the valence electrons for the Lv4+ ion? (1 point)
The electronic configuration of Lv element is [tex]5f^{14} 6d^{10} 7s^2 7p^4[/tex].
The electronic configuration of [tex]Lv^{+4}[/tex] is [tex]5f^{14} 6d^{10} 7s^2[/tex] .
What is electronic configuration?Electronic configuration, also called electronic structure, is the arrangement of electrons in energy levels around an atomic nucleus.
And also the possible union with hydrogen can give two possible compounds:
[tex]LvH_2 \;or LvH_4[/tex]
This is because the Livermorio compound can have two different oxidation states with the values 2 and 4. When reacting with the hydrogen that its charge is +1, these would be the two possible equations of a client to the different oxidation states with the ones that might react Lv.
It is a synthetic chemical compound and its number in the periodic table is 116.
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#1
Atomic no=116
Lies ahead of Renedium -86
Electronic configuration
[Rn]5f¹⁴6d¹⁰7s²7p⁴#2
Lv^4+ means 4 electrons donated
So it gets removed from p orbital
[Rn]5f¹⁴6d¹⁰7s²
The properties of an element depend on the electron structure within its atoms. The electrons are arranged in different
orbitals, at different energy levels and sublevels. Match each sublevel to the maximum number of electrons it can
accommodate?
The electrons are arranged in different orbitals, at different energy levels and sublevels.
What are Orbitals ?An atomic orbital is a function describing the location and wave-like behavior of an electron in an atom.
This function can be used to calculate the probability of finding any electron of an atom in any specific region around the atom's nucleus.
Following are the sublevel with the maximum number of electrons that can be accommodated by it ;
2 Electrons : S-SubshellTherefore, S-Subshell has 2 electrons, P-subshell has 3 electrons, d-subshell has 10 electrons and f-subshell has 14 electrons.
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How many grams of copper
➪ State the difference between molarity(M) and molality (m) ?
[tex]\sf{}[/tex]
⛄
How many grams of glucose (C6H12O6) are contained in 555 mL of a 1.77 M glucose solution?
176.980176 g of glucose ([tex]C_6H_{12}O_6[/tex]) are contained in 555 mL of a 1.77 M glucose solution.
What are moles?A mole is defined as 6.02214076 × [tex]10^{23}[/tex] of some chemical unit, be it atoms, molecules, ions, or others. The mole is a convenient unit to use because of the great number of atoms, molecules, or others in any substance.
[tex]Molality = \frac{Moles \;solute}{Volume \;of \;solution \;in \;litre}[/tex]
[tex]1.77 M = \frac{Moles \;solute}{0.555 L}[/tex]
mole solute = 0.98235 g/mol
[tex]Moles = \frac{mass}{molar \;mass}[/tex]
[tex]0.98235 g/mol = \frac{mass}{180.16 g/mol}[/tex]
mass = 176.980176 g
Hence, 176.980176 g of glucose ([tex]C_6H_{12}O_6[/tex]) are contained in 555 mL of a 1.77 M glucose solution.
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Please show steps Thanks
Answer:
chuma ya ndoshi.............
Explanation:
.
kwenda ukalale .............
What are other portals of entry besides needlesticks?
Answer:
Inhalation (via the respiratory tract)Absorption (via mucous membranes such as the eyes) Ingestion (via the gastrointestinal tract)
Explanation:
The opening where an infectious disease enters the host's body such as mucus membranes, open wounds, or tubes inserted in body cavities like urinary catheters or feeding tubes.
Write and balance molecular equations for the following reactions between aqueous solutions. You will need to decide on the formulas and phases of the products in each of the cases.
An aqueous solution of barium hydroxide is mixed with an aqueous solution of sulfuric acid.
Answer:
Ba(OH)2(aq) + H2SO4(aq) ----> BaSO4(s) + 2H2O(l)
Design a controlled experiment to test your hypothesis. A controlled experiment is one that only tests one variable. All other variables must remain the same. Make a drawing below that shows how you will set up your experiment. Then, write a description of the one factor that will vary and the two factors that will remain the same.
The problem is not found here but a possible experiment might be to measure the amount of product from a chemical reaction.
What is an experiment?An experiment is a procedure used to verify a working hypothesis obtained by applying the scientific method.
Experimental variables that can be tested include, for example, temperature, amount of product from a chemical reaction, etc.
In conclusion, the problem is not found here but a possible experiment might be to measure the amount of product from a chemical reaction.
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What is the electron configuration of a sodium atom?
1s¹, 2s², 2p6, 356
1s¹, 2s2, 2p6, 3s¹
2s², 2s², 2p6, 3s¹
1s², 2s², 2p6, 3s¹
Answer:
1s²,2s²,2p6,3s¹.Atomic no. of sodium is 11electronic configuration = 2,8,1.that Is 1s²,2s²,2p6,3s1.for electromic configuration - only 2 electron can be there in a single orbital there are 1 s orbital, 3 p orbital ...and so on.What kind of reaction is symbolized by AB + CD → AD + CB?
O A. Decomposition
OB. Synthesis
O C. Double replacement
OD. Single replacement
C. Double replacement
cations and anions switch places
Which of the following is not a type of covalent bond?
A. Quadruple
B. Double
C. Polar
D. Non-polar
Answer:
Quadruple
Explanation:
Answer:
A
Explanation:
7. What produces more severe burns, boiling water or steam?
Answer:
boiling water
Explanation:
boiling water produces more severe burns
What are the blue and yellow circles, the red circles, and the darkest blue ?
Answer:
The Red Circles: Liquid, Blue and Yellow Circles: Solid, and Purple Circles: Gas
Explanation:
Should be it based on the picture and given information.
How do models help scientists predict the polarity of molecules?
This is from the Molecular Structure Lab Report: Determining Polarity
In conclusion, modeling is very useful for predicting molecular polarity because chemical bonds among different atoms are generated to equal electrical charges.
What is molecular polarity?Molecular polarity refers to the unequal distribution of electrical charges in the atoms of a molecule.
This unequal distribution leads to the generation of molecular poles (positive and negative) at the ends of the chemical bonds.
In conclusion, modeling is very useful for predicting molecular polarity because chemical bonds among different atoms are generated to equal electrical charges.
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Calculate the number of Pt atoms in the cube and find the radius in picometers of a Pt atom. Be sure your answer has the correct number of significant digits. Full questions are in pictures...Thank you!
V cube = 2.2³ = 10.648 cm³
V Pt atoms = 0.75(75%) x 10.648 = 7.986 cm³
Part 1
mass of a single Pt atom = 3.24 x 10⁻²² g
mass Pt atoms = ρ x V = 21.45 g/cm³ x 7.986 cm³ = 171.3 g
the number of Pt atoms = 171.3 : 3.24 x 10⁻²² = 5.287 x 10²³
Part 2
4/3πr³=7.986 cm³
r = 1.24 cm = 1.24 x 10¹⁰ pm
