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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When 50.0 g of calcium carbonate are reacted with sufficient hydrochloric acid, how many grams of calcium chloride will be produced
Answer:
55.5g of calcium chloride is produced in the reaction.
Explanation:
To calculate the amount of calcium chloride.
The reaction of calcium carbonate with hydrochloride acid gives calcium chloride
CaCO₃ + 2HCl → CaCl₂ + CO₂ + H₂O
Mass of calcium carbonate (CaCO₃)= 50.0g
Molecular mass of CaCO₃ = Ca + C + O₃
= 40+ 12 + 3(16) = 100g
No of moles of calcium carbonate CaCO₃ = given mass / molecular mass
= 50g/ 100
= 0.5 moles
Molecular mass of calcium chloride = 40+ 2(35.5)=(40+71.0)= 111g/mol
1 mole of calcium carbonate gives = 1 mole of calcium chloride
0.5 moles of calcium carbonate gives= 0.5 × 111g/mole
= 55.5g
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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
What happens as a result of the photoelectric effect? A.light is produced
Answer:
photoelectric effect, phenomenon in which electrically charged particles are released from or within a material when it absorbs electromagnetic radiation. The effect is often defined as the ejection of electrons from a metal plate when light falls on it.
hello can you please help me
define x-ray with examples and it's uses?
Answer:
an x-ray a photographic or digital image of the internal composition of something, especially a part of the body, produced by X-rays being passed through it and being absorbed to different degrees by different materials.
examples
Abdominal x-ray.
Barium x-ray.
Bone x-ray.
Chest x-ray.
Dental x-ray.
Extremity x-ray.
Hand x-ray.
Joint x-ray.
Explanation:
its uses
An X-ray is a common imaging test that's been used for decades. It can help your doctor view the inside of your body without having to make an incision. This can help them diagnose, monitor, and treat many medical conditions.
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Show work pls.
2 moles of ZnO are produced if 1 mole of Zn and 2 moles of [tex]O_2[/tex] is required.
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.
Balanced equation:
[tex]2 Zn + O_2[/tex] → [tex]2 ZnO[/tex]
For 2 moles of Zinc, we need 1 mol of Oxygen to produce 2 moles of Zinc oxide
For 1 mole Zn, we need 2 mol [tex]O_2[/tex] to produce 2 moles ZnO only.
Hence, 2 moles ZnO is produced.
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what item is made from a synthetic material
Synthetic materials are made from natural resources and can be used for many purposes.
What is synthetic material ?Synthetic materials are made by chemically changing the starting substances to create a material with different characteristics. Some examples of synthetic materials are plastics, medicines, and new fuels.
A synthetic substance may be chemically identical to a naturally-occurring substance or may be different.
Item is made from a synthetic material :
Plastic bagPlastic bottleDisposable diaperSynthetic fiber/cloth (polyester, nylon, or rayon)KevlarArtificial sweetenerSynthetic fuel (Synfuel)Synthetic rubberChloroquine (Malaria drug)Taxol(Cancer drug)Physostigmine (Glaucoma drug)Aspirin
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If 6.34 g of CuNO, is dissolved in water to make a 0.720 M solution, what is the volume of the solution in milliliters?
V=n/M
V=(6.34:125.55 g/mol)/0.72
V=0.07 L = 70 ml
Which reaction is endothermic
Answer:
Option 3
Explanation:
Heat is absorbed, so the reaction is endothermic.
A cup of water is warmed from 29 °C to 97 °C. What is the difference between these two temperatures, in kelvins
Answer:
I believe it is 68
Explanation:
to convert Celsius to kelvins you must add it to 273.15 for example 29 + 273.15 is 302.15
im so very sorry if im wrong.
What is the molar concentration of Zn2+ ions in a solution, if the electrode potential value is 59mV less than the standard electrode potential value at 298 K?
Molar concentration of Zn2+ions in a solution is 3.481 mol/lit
The electrode potential value is 59mV
Temperature=298k
What is electrode potential?
It is a force of galvanic cell. basically it is the difference between an electrolyte and electrode.equation formed- Zn → Zn2+ + 2e
from Nernst equation-
E=E cell - 0.059 log [Zn2+]
[zn2+]=3.481 mol/lit
hence, Molar concentration of Zn2+ions in a solution is 3.481 mol/lit
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How many moles of HCl are required to react with 1 g of zinc?
Answer:
Explanation:
To solve problems like this, the very first thing to do is to write out the balanced equation for the process. The reaction is
Zn(s) + HCl(aq) → ZnCl2(aq) + H2(g)
and the balanced equation is
Zn(s) + 2 HCl(aq) → ZnCl2(aq) + H2(g)
So, by examining the stoichiometry, you can see that for every mole of Zn, two moles of HCl will be required. In turn, we need to know the number of moles of Zn is represented by 10.4 g. The molecular weight of Zn is 65.38 g/mol so
moles of Zn = 10.4 g/65.38 g/mol = 0.159 moles
and, twice as many moles of HCl is required so
# of moles of HCl required = 2 * 0.159 = 0.318 moles
What would be the mass, in grams, of 2.408 x 1024 molecules of tetraphosphorus decaoxide?
Answer:
1,135 grams P₄O₁₀
Explanation:
To find the mass, you need to (1) convert molecules to moles (via Avogadro's Number) and then (2) convert moles to grams (via molar mass from periodic table values). It is important to arrange the ratios/ conversions in a way that allows for the cancellation of units (the desired unit should be in the numerator). The final answer should have 4 sig figs to reflect the given value (2.408 x 10²⁴).
Avogadro's Number:
1 mole = 6.022 x 10²³ molecules
tetraphosphorus decaoxide = P₄O₁₀
Molar Mass (P₄O₁₀): 4(30.974 g/mol) + 10(15.998 g/mol)
Molar Mass (P₄O₁₀): 283.876 g/mol
2.408 x 10²⁴ molecules P₄O₁₀ 1 mole 283.876 g
------------------------------------------- x ------------------------------------ x -----------------
6.022 x 10²³ molecules 1 mole
= 1,135 grams P₄O₁₀
Which of the following is an example of a metamorphic rock?
Granite
Limestone
Marble
Pumice
Answer:
C
Explanation:
Marble is the correct answer
How many molecules in HNO3?
determine how many grams of N2 are produced from the reaction of 8.73
g of H2O2 and 5.16
g of N2H4.
Taking into account the reaction stoichiometry, 4.515 grams of N₂ can be produced from 8.73 grams of H₂O₂ and 5.16 grams of N₂H₄.
Reaction stoichiometryIn first place, the balanced reaction is:
N₂H₄ + 2 H₂O₂ → N₂ + 4 H₂O
By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:
N₂H₄: 1 mole H₂O₂: 2 molesN₂: 1 mole H₂O: 4 molesThe molar mass of the compounds is:
N₂H₄: 32 g/moleH₂O₂: 34 g/moleN₂: 28 g/moleH₂O: 18 g/moleThen, by reaction stoichiometry, the following mass quantities of each compound participate in the reaction:
N₂H₄: 1 mole ×32 g/mole= 32 gramsH₂O₂: 2 moles ×34 g/mole= 34 gramsN₂: 1 mole ×28 g/mole= 28 gramsH₂O: 4 moles ×18 g/mole= 18 gramsLimiting reagentThe limiting reagent is one that is consumed first in its entirety, determining the amount of product in the reaction. When the limiting reagent is finished, the chemical reaction will stop.
Limiting reagent in this caseTo determine the limiting reagent, it is possible to use a simple rule of three as follows: if by stoichiometry 34 grams of H₂O₂ reacts with 32 grams of N₂H₄, 8.73 grams of H₂O₂ reacts with how much mass of N₂H₄?
[tex]mass of N_{2} H_{4} =\frac{8.73 grams of H_{2} O_{2}x 32 grams of N_{2} H_{4} }{34grams of H_{2} O_{2}}[/tex]
mass of N₂H₄= 8.22 grams
But 8.22 grams of N₂H₄ are not available, 5.16 grams are available. Since you have less mass than you need to react with 8.73 grams of H₂O₂, N₂H₄ will be the limiting reagent.
Mass of N₂ formedConsidering the limiting reagent, the following rule of three can be applied: if by reaction stoichiometry 32 grams of N₂H₄ form 28 grams of N₂, 5.16 grams of N₂H₄ form how much mass of N₂?
[tex]mass of N_{2} =\frac{5.16 grams of N_{2} H_{4} x28 grams of N_{2}}{32 grams of N_{2} H_{4} }[/tex]
mass of N₂= 4.515 grams
Then, 4.515 grams of N₂ can be produced from 8.73 grams of H₂O₂ and 5.16 grams of N₂H₄.
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can you please answer it I need it now
thanks.
Answer:
1. Thermometer– It is used to measure air temperature.
2. From time to time– In 2–4hrs after sunrise, the air temperature rises the fastest. Around 1hr before sun set, the air temperature drops the fastest. The solar radiation reaches its highest value at noon.
3. Anemometer– it is used to measure wind speed and direction.
4. Direction– The wind vane originally measures the direction of the wind, but, some modern ones have wind cups attached to them, to measure the wind speed.
5. Anemometer– It is a device that measures wind speed and direction. These, days, some modern wind vanes also measure wind speed.
Explanation:
I hope this helps.
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.
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One mole of hydrogen is burned in oxygen to produce water in the gas phase, H = 285.8 kJ. What is the energy change when 1 mole of water, in the gas phase, decomposes to form hydrogen and oxygen? a.142.9 kJ of heat is absorbed. b.285.8 kJ of heat is absorbed. c.142.9 kJ of heat is released. d.285.8 kJ of heat is released.
When One mole of hydrogen is burned in oxygen to produce water in the gas phase, 285.8 kJ of heat is released.Hence, option (D) is correct
What is Enthalpy change ?An enthalpy change is approximately equal to the difference between the energy used to break bonds in a chemical reaction and the energy gained by the formation of new chemical bonds in the reaction.
It describes the energy change of a system at constant pressure. Enthalpy change is denoted by ΔH.
The energy change that occurs when one mole of a compound is burnt in excess oxygen under standard bis called the standard enthalpy change of combustion.
Hence, When One mole of hydrogen is burned in oxygen to produce water in the gas phase, 285.8 kJ of heat is released.Thus, option (D) is correct
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5 grams of sodium chloride is dissolved to make 0.5 L of solution
The concentration of the solution is 0.17M
The missing question is
What is the concentration of the solution ?
What is Molarity ?Molarity is the moles of solute in 1 liter of solution.
It is the measure of concentration of a solution in mol/l .
It is given that
5 grams of sodium chloride is dissolved to make 0.5 L of solution
the concentration of the solution
Molecular weight of Sodium Chloride = 58.44 g
58.44 g of NaCl = 1 mol
5g of NaCl = 5/58.44 = 0.086 moles
Molarity = 0.086 / 0.5
Molarity = 0.17 M
The concentration of the solution is 0.17M
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Imagine that a single cell below goes through four cell divisions. How many cells are produced? To find out, draw the parent cell and cells present after each division. Then write the number of cells in the space below each drawing. (Hint: the number of cells doubles with each division.)
16 cells are produced from a single parent cell after the fourth division of the cell.
What is a cell?In biology, the smallest unit can live on its own and that makes up all living organisms and the tissues of the body.
In mitosis type of cell division, one parent cell is divided into two same or different daughter cells. In this way, in the first division, two cells are produced from single parent cells and in the second division, four daughter cells are produced. In the third division, 8 cells are produced from 4 parent cells and in the fourth division, 16 cells are formed from 8 cells.
So we can conclude that 16 cells are produced from a single parent cell after the fourth division of the cell.
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Which of the following industries is leaching used in?
To separate a metal from its ore using acid and preserving desirable products such as gold.
To separate a mixture of ethanol and water
To separate a slurry containing chalk and water
None of the above.
Answer:
To separate a metal from its ore using acid and preserving desirable products such as gold.
Explanation:
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Use Table B in your Student Guide to answer the questions about ion concentrations.
A solution with a pH = 13 has approximately how many moles of OH ions per liter?
How many moles of H* would this same solution have per liter?
(Use the decimal form of your answer.)
A different solution with an H+ concentration of 1.0 x 10-4 would have a pH =
Question 1
[tex]\text{pH}=-\log(\text{H}^{+})\\\\13=-\log(\text{H}^{+})\\ \\ \text{[H}^{+}]}=1 \times \boxed{10^{-13} \text{ moles per liter}} \\ \\ \text{[H}^{+}] \times \text{[OH}^{-}] =1 \times 10^{-14} \text{ M}\\\\\text{[OH}^{-}]=\boxed{1 \times 10^{-1} \text{ moles per liter}}[/tex]
Question 2
[tex]\text{pH}=-\log(\text{H}^{+})\\\\\text{pH}=-\log(1.0 \times 10^{-4})=\boxed{4}[/tex]
a specialist that study substance obtained by attained mining is called a what
Answer:
Explanation:
Mining:
Mining is when certain substances are removed from the Earth, usually in large quantities. Mining can occur below the surface of the Earth via tunnels and caves. It can also occur at surface level through methods such as strip mining, which removes huge amounts of soil in the process
How many grams of glucose (C6H12O6) are contained in 555 mL of a 1.77 M glucose solution?
Which is the most likely to be reduced?
OA. Cu²+
OB. Zn²+
OC. Fe³+
OD. Fe2+
Answer:
OC. Fe³+
Explanation:
Greater reduction potential (bigger positive E value) means that things wants to get electrons. For this, you have to look at the chart that I have attached. Since, Fe3+ has highest E value out of other options, it will likely be reduced.
The species which is most likely to get reduced is Fe³⁺.
What is Reduction?Reduction is the process of the addition of electrons and loss of oxygen atoms. It is part of redox reactions.
Redox reactions are the type of reactions in which oxidation and reduction simultaneously take place. Oxidation is the addition of oxygen atoms. Reduction is the removal of oxygen atoms.
Redox reaction can be represented as:
PbO (s) + H₂ (g) → Pb(s) + H₂O (l)
In the above reaction, PbO is getting reduced and H₂ is getting oxidized.
Fe³⁺ is most likely to get reduced because the more positive the value of reduction potential, the more will be its tendency to get reduced.
In the given four species, the value of the reduction potential of Fe³⁺ is the highest.
Values of the reduction potential of four species are:
Cu²⁺ = 0.34Zn²⁺ = - 0.76Fe³⁺ = 0.77Fe²⁺ = -0.45Learn more about, redox reactions:
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Determine the hybrid orbital of this molecule.
There are three sigma bonds, so hybridization of the molecule will be sp²
For the following reaction, 41.0 grams of sulfuric acid are allowed to react with 36.5 grams of zinc hydroxide. What is the maximum amount of zinc sulfate that can be formed? Mass = g What is the FORMULA for the limiting reactant? What amount of the excess reactant remains after the reaction is complete? Mass = g
The FORMULA for the limiting reagent is [tex]ZnOH_2[/tex].
4.27 grams of reactant remains after the reaction is complete.
What is a limiting reagent?The limiting reagent is the reactant that is completely used up in a reaction and thus determines when the reaction stops.
Given data:
Mass of sulfuric acid = 41.0 grams
Molar mass of sulfuric acid = 98.08 g/mol
Mass of zinc hydroxide = 36.5 grams
Molar mass of zinc hydroxide = 99.424 g/mol
Step 1:moles sulfuric acid = mass sulfuric acid / molar mass sulfuric acid
moles sulfuric acid = 41.0 grams / 98.08 g/mol
moles sulfuric acid = 0.41 moles
Step 2: moles of zinc hydroxide
moles zinc hydroxide = 36.5 grams / 99.424 g/mol
moles zinc hydroxide =0.367 moles
Step 3: Calculate limiting reactant
zinc hydroxide is the limiting reactant. It will completely be consumed.
There will remain 0.41 moles - 0.367 moles = 0.043 moles
This is 0.043 moles x 99.424 g/mol
= 4.27 grams
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2. Grapes, when tested with Benedict's reagent, gave brick red colour, whereas the iodine test didn't show any colour change.
A. What does the test results indicate about grapes?
B. Rice contains complex carbohydrates. If grapes are substituted with rice, what would be the test result?
Rice would not show any negative test with Benedicts solution but will show blue black color with iodine.
What is the Benedicts solution?The Benedicts solution is used to test for the presence of reducing sugars in a solution. The brick red color is a positive test for reducing sugars such as glucose.
Owing to the fact that grape does not have starch, it shows a negative test for starch. Rice would not show any negative test with Benedicts solution but will show blue black color with iodine.
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light frequency 1.40x10^15 Hz strike a surface causing photoelectrons to leave with a KE of 1.05 eV what is the work function in eV
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 empirical formula for a compound composed of 0.0683 mol of carbon ( C ), 0.0341 mol of hydrogen ( H ), and 0.1024 mol of nitrogen ( N )?
The empirical formula for a compound composed of 0.0683 mol of carbon ( C ), 0.0341 mol of hydrogen ( H ), and 0.1024 mol of nitrogen ( N ) is [tex]C_2HN_3[/tex].
What is the empirical formula?An empirical formula tells us the relative ratios of different atoms in a compound.
Given data:
Moles of carbon = 0.0683 mol
Moles of hydrogen = 0.0341 mol
Moles of nitrogen = 0.1024 mol
Dividing each mole using the smallest number that is divided by 0.0341 moles.
We get:
Carbon= 2
Hydrogen=1
Nitrogen=3
The empirical formula for a compound is[tex]C_2HN_3[/tex].
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