Answer:
The Work Function is 4.74eV.
Explanation:
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
= frequency of the incident light beam
₀ = frequency of the photoelectrons
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
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Write and balance the equation for the combustion of the fatty acid lauric acid, (C12H24O2)
.
Express your answer as a chemical equation. Identify all of the phases in your answer.
The combustion of lauric acid is shown as CH3(CH2)10COOH(s) + 18O2(g) -----> 12H20(l) + 12CO2(g)
What is combustion?In a combustion reaction, a substance is burnt in oxygen. If the substance is an organic compound a the case is here, the products are carbon dioxide and hydrogen.
No the equation of the combustion of lauric acid is shown as;
CH3(CH2)10COOH(s) + 18O2(g) -----> 12H20(l) + 12CO2(g)
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Barium nitrate (Ba(NO3)2) reacts with sodium chloride (NaCl) in a double replacement (displacement) reaction, shown below.
Ba(NO3)2(aq)+NaCl(aq)-->???
How many grams of barium salt are produced when a solution containing 21.7 g of Barium nitrate is mixed with a solution containing excess sodium chloride?
Use 261.34 as the molar mass for barium nitrate. Round to three significant digits.
Answer:
you know that they will be a displacement reaction that will form a barium salt:
Ba(NO3)2+ 2NaCl--> BaCl2 + 2NaNO3
So now that we have that formula and the molecular weight we can determine how much salt will be made. So here we convert the grams to moles
(42.3g Ba(NO3)2)*(1 mole/261.34g) = 0.16185 mol
In the molecular formula we know that 1 mole of Barium nitrate will create 1 mole of Barium chloride, so in this case (in a perfect world) you should get 0.16185 mole of barium chloride (208.23 g/mol) that we then have to convert to grams.
(0.16185 mol BaCl2) * ( 208.23 g/mol) = 33.7037 g of Barium Chloride (rounded to 3 significant digits = 33.7g)
Explain how they would make solutions of the sulfuric acid at five different concentrations
The sulfuric acid can be constituted into different concentrations using distilled water as a diluent.
What is dilution of acid?Dilution of acid is defined as the decrease in the concentration of an acid using water.
For sulfuric acid to be diluted, it is slowly added to distilled water using the following guidelines:
Add 150 ml of water to the beaker and add the desired amount of acid. This will give a diluted concentration of the given acid.Learn more about acid here:
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How many moles of O2 are consumed when 2.10 mol of magnesium burns?
1.05 moles of oxygen gas are consumed in the reaction when 2.10 mol of magnesium burns.
What are moles?A mole is defined as [tex]6.02214076 × 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.
We are given:
Moles of magnesium = 2.10 mol
For the given chemical reaction:
2Mg + O₂ → 2MgO.
By Stoichiometry of the reaction:
2 moles of magnesium react with 1 mole of oxygen gas.
So, 2.10 moles of magnesium will react with = [tex]\frac{1}{2}[/tex] X2.10 =1.05 moles
Hence, 1.05 moles of oxygen gas are consumed in the reaction.
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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
Sort the length measurements in increasing order of magnitude from smallest to largest.
The length measurements in increasing order of magnitude from smallest to largest is Nanometer, micrometer, centimeter, decimeter, dekameter, kilometer.
What is Measurement ?Measurement is the quantification of attributes of an object or event, which can be used to compare with other objects or events.
Measurement is a process of determining how large or small a physical quantity is as compared to a basic reference quantity of the same kind.
Hence, Among the given length measurements, The increasing order of magnitude from smallest to largest is Nanometer, micrometer, centimeter, decimeter, dekameter, kilometer.
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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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You are watching tv and you see something on the corner of your eye what do you do and you're home alone
Talk to the doctor if you see something in the corner of your eye.
What is a visual hallucination?Visual hallucinations involve seeing things that aren't there.
It's called a visual hallucination, and it can seem like your mind is playing tricks on you. Beyond being scary or stressful, it's also usually a sign that something else is going on.
So if it's happening to you, talk to your doctor. That's the first step toward getting better.
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What does the prefix cis-in the name of a stereoisomer indicate about the
functional groups?
2022
DP Chemistry Practical Guide
Dission Questions
Why are the burette and the pipette rinsed with the solution with which these are filled?
Answer:
OOO
Explanation:
OOOOOO
1. For CCl4, upload a photo including the following: (1) work arriving at total # valence electrons
(2) hand drawn Lewis structure (3) molecular model (4) signature(s) and (5) date.
Work arriving at total valence electrons are 24
The valence electron is an electron in the outer shell associated with an atom, and that can participate in the formation of a chemical bond
For a main-group element, a valence electron can exist only in the outermost electron shell; for a transition metal, a valence electron can also be in an inner shell.
Lewis structures, also known as Lewis dot formulas, Lewis dot structures, electron dot structures, or Lewis electron dot structures (LEDS), are diagrams that show the bonding between atoms of a molecule, as well as the lone pairs of electrons that may exist in the molecule.
Calculating the work arrival at total valence electrons
We know 1 bond contains
2 valence electrons
Here CCl4 contains 4 bonds that is 8 valence electrons
Therefore ,
Total valence electrons are 32
Now valence electrons remain after bond formation =
32 - 8
=24 valence electrons
A molecular model is a physical model of an atomistic system that represents molecules and their processes
Molecular image and lewis hand drawn structure is as shown below
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diffrentiate between equation and chemical formula
A chemical equation is the symbolic representation of a chemical reaction in the form of symbols and formulae, wherein the reactant entities are given on the left-hand side and the product entities on the right-hand side with a plus sign between the entities in both the reactants and the products and an arrow that points towards the products, and shows the direction of the reaction. The coefficients next to the symbols and formulae of entities are the absolute values of the stoichiometric numbers. The first chemical equation was diagrammed by Jeen Beguin in 1615.
A chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols, such as parentheses, dashes, brackets, commas and plus and minus signs.
Hope this helps you!
Answer:
Explanation:
Chemical Formula:Represents the composition of a substance or compoundUses symbols and subscripts to indicate the types and numbers of atoms in a moleculeExample: H2O represents the chemical formula for waterChemical Equation:Represents a chemical reactionShows the reactants and products involved in the reactionUses chemical formulas and symbolsReactants are on the left side, products on the right side, separated by an arrowExample: 2H2 + O2 → 2H2O represents the reaction of hydrogen gas and oxygen gas to form waterIn summary:Formula describes composition, equation describes a reactionFormula uses subscripts for atom count, equation uses symbols and arrowsQuestion 4 of 15
A compound with the empirical formula CH₂ has a molar mass of 42 g/mol. What is the molecular formula for this compound?
molecular formula:
3CH₂
Attempt 1
Incorrect
(CH₂)n=42
(14)n=42
n=3
C₃H₆
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
In a recent study, 50 males used a new weight-loss supplement, and 37 of them experienced weight loss after two weeks: In the same study, 20 females used
the same supplement, and 13 of them experienced weight loss after two weeks.
Fill in the blanks below to make the most reasonable statement possible.
The new weight-loss supplement was less effective on (Choose one) in the study. That is because only % of them lost
weight after two weeks, whereas % of the (Choose one) lost weight after two weeks.
Answer:
The new weight-loss supplement was less effective on females in the study. That is because only 65% of them lost weight after two weeks, whereas 74% of the males lost weight after two weeks.
Explanation:
37 out of 50 males lost weight after two weeks, so 74% of males lost weight ( (37 · 2)/(50 · 2) ). 13 out of 20 females lost weight after two weeks, so 65% of females lost weight ( (13 · 5)/(20 · 5) ). This means the supplement was less effective on females because males had a higher percentage of losing weight.
Hope this helps !! :D
What is the isomer of a compound with an empirical formula of C₂H₆O₂?
Answer:
An isomer is a molecule with the same molecular formula as another molecule, but with a different structure. Isomers contain the same number of atoms of each element, but have different arrangements of their atoms. Isomers do not necessarily share similar properties, unless they also have the same functional groups.
What is the concentration of acetic acid if three 65.0 mL samples of actic acid were neutralized with 16.8 mL, 18.2 mL, and 17.35 mL of 0.5.00 M KOH. (Hint: KOH and acetic acid react in a 1 to 1 mole ratio)
M₁V₁=M₂V₂
65 x M₁ = 16.8 x 0.5
M₁ = 0.129
65 x M₁ = 18.2 x 0.5
M₁ = 0.14
65 x M₁ = 17.35 x 0.5
M₁ = 0.133
Average = 0.129 + 0.14 + 0.133 = 0.134 M
The absolute molar entropies of O2 and N2 are 205 J K-1 mol -1 and 192 J K-1 mol-1, respectively, at 25°C. What is the entropy of a mixture of 2.4 moles of 02 and 9.2 moles of N2 at the same temperature and pressure?
The entropy of a mixture is 96.44J K-1 mol -1
The absolute molar entropies of O2= 205 J K-1 mol -1 The absolute molar entropies of N2=192 J K-1 mol -1 Moles of O2 present(m)=2.4Moles of N2 present(n)=9.2The formula for calculating the entropy of a mixture-
Δ[tex]S_{mix} =[/tex][tex]-nR(X_{O2} ln_{XO2} +X_{N2} lnX_{N2})[/tex]
X=mole fraction
total no. of moles(t)=m + n
=2.4+9.2
=11.6 moles
now substituting the values-
entropy of mix=-11.6R(2.4/11.6 + 9.2/11.6)
=11.6R
( R=8.314 ) =11.6×8.314
=96.44J K-1 mol -1
hence, The entropy of a mixture is 96.44J K-1 mol -1
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How many atoms are in 2.17 moles of strontium?
Answer: I think 82.46
Explanation: The atomic number for strontium, or Sr on the periodic table, is 38. With knowing the atomic number, I multiplied that by the number of moles given.
38 × 2.17 = 82.46
I hope this helps!!
The number of atoms present in 2.17 moles of strontium are [tex]1.306774 \times 10^{24}[/tex].
An atom is the smallest indivisible unit of a chemical element that retains the chemical properties of that element. It is the basic building block of matter.
To determine the number of atoms in a given number of moles, we can use Avogadro's number, which is approximately [tex]6.022 \times 10 ^{24}[/tex] atoms per mole.
In this case, we have 2.17 moles of strontium. To find the number of atoms, we multiply the number of moles by Avogadro's number:
Number of atoms = [tex]2.17 moles\times6.022\times 10^{23}[/tex][tex]atoms/mole[/tex]
On calculating this expression:
Number of atoms =[tex]1.306774 \times 10^{24}[/tex]
Therefore, there are approximately [tex]1.306774 \times 10^{24}[/tex] atoms in 2.17 moles of strontium.
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After scientists use a careful process to gather evidence and establish scientific facts, which step most likely occurs next in the scientific process? conducting experiments testing new conditions Ostudying new topics determining explanations After scientists use a careful process to gather evidence and establish scientific facts , which step most likely occurs next in the scientific process ? conducting experiments testing new conditions Ostudying new topics determining explanations
Answer:
Conducting Experiments
Pleaseee help pleaseee!!!
NaClO₃ ⇒ NaCl + O₂ ⇒ unbalanced
1. O : left 3, right 2
give coefficient left 2, right 3
2NaClO₃ ⇒ NaCl + 3O₂
2. Na and Cl : left 2, right 1
give coefficient right 2
2NaClO₃ ⇒ 2NaCl + 3O₂ ⇒ balanced
Convert -145 °F to kelvins. Round to the nearest whole number.
Answer:
175K
Explanation:
(-145°F − 32) × 5/9 + 273.15 = 174.817K
174.817 ---> 175 (Rounded to whole number/ ones place)
What is the number of elements in 2Ca(OH)2
In the following half equation, which is the oxidizing agent? How & why?
NO3- (aq) + 4H+ (aq) + 3e- —> NO (g) + 2H2O
A) NO3-
B) H+
C) e-
D) NO
E) H2O
Answer: A
Explanation:
Oxidation is the process through which electrons are gained. This indicates that only organisms on the electron side have the potential to be oxidizing agents. c, d, and e are, by definition, eliminated.
We also know that H+ is in the +1 oxidation state. The same is true for 'H' in H2O... it doesn't change oxidation states
Therefore, the answer must be a) nitrate
acid base and solutions
The Arrhenius definition of an acid states that an acid ionizes or dissociates to from hydroxide ions in solution.
What is the Arrhenius definition of acid?The definition of solutions was more given by the traditional scientist in smart solutions, which are natural solutions, like substances that - easy solutions, aqueous like bases.
In this case, Arrhenius definition of an acid states that an acid ionizes or dissociates to from hydroxide ions in solution.
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A tank holds 22.1 L of oxygen ( O2 ) at a pressure of 18.0 atm . What is the final volume, in liters, of this gas when it is released at a pressure of 2.90 atm with no change in temperature and amount of gas.
The final volume of gas will be 137.17L .
According to ideal gas equation , PV=nRT , where P is pressure of gas , V is volume of gas , n is moles of gas , R is universal gas constant and T is the temprature of gas.
Now , according to the que at initial and final stage the temprature and amount of gas stays constant , so we would simply equate the initial PV to the final PV.
⇒[tex]P_{i} V_{i} = P_{f} V_{f} \\[/tex]
where [tex]P_{i}[/tex] ans [tex]V_{i}[/tex] are the initial pressure and volume of the gas and [tex]P_{f}[/tex] and [tex]V_{f}[/tex] are the final pressure and volume of the gas .
Here we have to find final volume of gas .
So , putting all values in above eq we get
18 x 22.1 = 2.9 x [tex]V_{f}[/tex]
⇒ [tex]V_{f}[/tex] = 137.17 L
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M1 = 3M M2 = 1.25M V1 = V1=.125L unkown What is V2?
0.3 L is the final volume when M₁ = 3 M, V₁ = 0.125L, M₂ = 1.25M.
What is volume?The amount of space occupied by a three-dimensional figure as measured in cubic units.
Given data:
M₁ = 3 M
V₁ = 0.125L
M₂ = 1.25M
V₂ = ?
Solution:
M₁V₁ = M₂V₂
3 M × 0.125L = 1.25M × V₂
V₂ = 0.3 L
Hence, 0.3 L is the final volume.
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what's the name of the compound?
examples of molecular compound
Answer:
Molecular compounds are inorganic compounds that take the form of discrete molecules. Examples include such familiar substances as water (H2O) and carbon dioxide (CO2). These compounds are very different from ionic compounds like sodium chloride (NaCl).
1) Consider this row in the periodic table. What changes can you predict based on what information is provided by the boxes for each element?
A) The elements change from solids to gases and the valence electrons decrease in number.
B) As you move across the row, the number of electrons increases and reactivity also increases.
C) They have different atomic numbers and mass numbers; they have the same number of valence electrons.
D) Both the atomic numbers and the mass numbers increase; the least reactive element is in the last box.
USA test prep question
Answer:
B) As you move across the row, the number of electrons increases and reactivity also increases.
Explanation:
The periodic table is arranged in a way that if you go across a period, the number of protons, neutrons, and electrons in an element increases. In terms of reactivity, the most reactive elements are the ones which have a high electronegativity. The electronegativity of the elements increases as you travel to the right and upwards on the periodic table.