Answer:
n = 1.3 x 10¹⁸ photons
Explanation:
First we need to calculate the amount of energy released in given time:
E = Pt
where,
E = Energy = ?
P = Power = 4 mW = 0.004 W
t = time = 115 s
Therefore,
E = (0.004 W)(115 s)
E = 0.46 J
Now, this energy can be given in forms of photons as:
E = nhc/λ
where,
n = No. of photons = ?
h = Plank's Constant = 6.626 x 10⁻³⁴ J.s
c = speed of light = 3 x 10⁸ m/s
λ = wavelength of light = 5650 x 10⁻¹⁰ m
Therefore,
0.46 J = n(6.626 x 10⁻³⁴ J.s)(3 x 10⁸ m/s)/(5650 x 10⁻¹⁰ m)
n = (0.46 J)/(3.5 x 10⁻¹⁹ J)
n = 1.3 x 10¹⁸ photons
Answer:
1.308 x 10¹⁸ photons were emitted from the laser pointer.
Explanation:
Given;
wavelength of the photon, λ = 5650 Å = 5650 x 10⁻¹⁰ m
power emitted by the source, P = 4 mW = 4 x 10⁻³ W
time of photon emission, t = 115 s
The energy of a single photon is given by;
E = hf
f = c / λ
[tex]E = \frac{h c }{\lambda}[/tex]
where;
c is speed of light = 3 x 10⁸ m/s
h is Planck's constant = 6.626 x 10⁻³⁴ Js
[tex]E = \frac{(6.626 *10^{-34}) (3*10^8) }{5650*10^{-10}}\\\\ E = 3.518*10^{-19} \ J[/tex]
Energy of the source (laser pointer) = P x t
= (4 x 10⁻³ W) (115 s )
= 0.46 J
If no energy is lost, then emitted energy by the source must be equal to total energy of then photons;
[tex]E_T = n E_{photon}\\\\n = \frac{E_T}{E_{photon}}\\\\n = \frac{0.46}{3.518*10^{-19}}\\\\n = 1.308*10^{18} \ photons[/tex]
Therefore, 1.308 x 10¹⁸ photons were emitted from the laser pointer.
What ions are present in an aqueous solution of NiCl2?
Answer:
Ni²⁺ and Cl⁻ ions
Explanation:
NiCl₂ is an ionic compound which is composed by 2 chloride ions (Cl⁻) and 1 nickel (II) ion (Ni²⁺). It dissociates in water as follows:
NiCl₂ ⇒ Ni²⁺ + 2 Cl⁻
Therefore, in an aqueous solution of NiCl₂ will be present Ni²⁺ ions and Cl⁻ ions.
Please help asap!! Need help for problem #2.
Naturally occuring iron, contains 5.82% ^54Fe, 91.66% ^56Fe, 2.19% ^57Fe, and 0.33% ^58Fe. The reslective atomic masses are 53.940 amu, 55.935 amu, 56.935 amu and 57.933 amu. Calculate the average atmoic mass of iron. (show work)
Answer:
55.56 amu
Explanation:
Let A, B, C and D represent the four isotopes of iron.
The following data were obtained from the question:
Isotope A (Fe-54):
Mass of A = 53.940 amu
Abundance (A%) = 5.82%
Isotope B (Fe-56):
Mass of B = 55.935 amu
Abundance (B%) = 91.66%
Isotope C (Fe-57):
Mass of C = 56.935 amu
Abundance (C%) = 2.19%
Isotope D (Fe-58):
Mass of D = 57.933 amu
Abundance (D%) = 0.33%
Average atomic mass =.?
The average atomic mass of the iron can obtained as follow:
Average atomic mass = [(mass of A × A%)/100] + [(mass of B × B%)/100] + [(mass of C × C%)/100] + [(mass of D × D%)/100]
Average atomic mass = [(53.940 × 5.82)/100] + [(55.935 × 91.66 )/100] + [(56.935 × 2.19)/100] + [(57.933 × 0.33)/100]
= 2.848 + 51.270 + 1.247 + 0.191
= 55.56 amu
Therefore, the average atomic mass of the iron is 55.56 amu
Observations made during an experiment are called
A cube has an edge length of 9 cm .
If it is divided up into 1-cm cubes, how many 1-cm cubes would there be?
Answer:
9^3 i think so like 279
Explanation:
blah
How many cm are in 29.7km?
Answer:
there are 2970000cm in 29.7km
Explanation:
is there any compound like O2C NO2
Answer:
Aye Wassup? Adam Here :D
Explanation:
Nitrogen dioxide is a chemical compound with the formula NO 2.It is one of several nitrogen oxides. NO 2 is an intermediate in the industrial synthesis of nitric acid, millions of tons of which are produced each year for use primarily in the production of fertilizers.At higher temperatures it is a reddish-brown gas.
Hope This Helped Bro: "AdamDaAssasin"
Chromium(III) oxide reacts with hydrogen sulfide (H2S) gas to form chromium(III) sulfide and water: Cr2O3(s) + 3H2S(g) → Cr2S3(s) + 3H2O(l) To produce 156 g of Cr2S3, (a) how many moles of Cr2O3 are required? mol (b) how many grams of Cr2O3 are required? g
Answer:
(a) 0.779 mol Cr₂O₃
(b) 118 g Cr₂O₃
Explanation:
Step 1: Convert 156 g Cr₂S₃ to moles
Cr Molar Mass - 52.00 g/mol × 2 = 104.00 g/mol
S Molar Mass - 32.07 g/mol × 3 = 96.21 g/mol
156 g Cr₂S₃ ÷ 200.21 g/mol = 0.779182 mol Cr₂S₃
Step 2: Find conversion from Cr₂S₃ to Cr₂O₃
1 mol Cr₂S₃ equals 1 mol Cr₂O₃
Step 3: Use Dimensional Analysis
0.779182 mol Cr₂S₃ · [tex]\frac{1 \hspace{2} mol \hspace{2} Cr_2O_3}{1 \hspace{2} mol \hspace{2} Cr_2S_3}[/tex] = 0.779182 mol Cr₂O₃
0.779182 mol Cr₂O₃ ≈ 0.779 mol Cr₂O₃ (3 significant figures)
Step 4: Convert moles to grams
Cr Molar Mass - 52.00 g/mol × 2 = 104.00 g/mol
O Molar Mass - 16.00 g/mol × 3 = 48.00 g/mol
0.779182 mol Cr₂O₃ · 152.00 g/mol = 118.436 g Cr₂O₃
118.436 g Cr₂O₃ ≈ 118 g Cr₂O₃ (3 significant figures)
You have two compounds that you have spotted on the TLC plate. One compound is more polar than the other. You ran the TLC plate with neat hexanes and found that only one spot moved a small distance up the plate. What might you expect to see if you ran a TLC plate in a 50/50 mixture of hexanes and ethyl acetate
Answer:
we will except an increase in the polarity of the system and this will cause the Non-polar spot to be near the solvent front, while the polar spot will run at an approximate speed of 0.5 Rf
Explanation:
when we run a TLC plate in a 50/50 mixture of hexanes and ethyl acetate we will except an increase in the polarity of the system and this will cause the Non-polar spot to be near the solvent front, while the polar spot will run at an approximate speed of 0.5 Rf
The speed of the polar spot depends largely on the level of polarity, an increase in the polarity will see both spots of Neat hexane run when we run a TLC plate in a 50/50 mixture of hexanes and ethyl acetate
what is biotic?check all that apply
Answer: biotic is Living things in their ecological relations.
Explanation:
what is formed when polyatomic ions bond with other ions.
A) ionic compounds.
B) neutral compounds.
C) ionic elements.
D) neutral elements.
Answer:
iconic compounds is your anwser
Answer:
Iconic Compounds
Explanation:
I watched a video about it.
Have a nice Friday!
3. Diesel fuel has a density of 0.839g/mL What is the volume, in gallons, of 2.3 kg of diesel? [1 gallon = 3.79 L)
Answer:
0.71 gal
Explanation:
Step 1: Given data
Density of Diesel (ρ): 0.839 g/mL
Mass of Diesel (m): 2.3 kg
Step 2: Convert "m" to grams
We will use the relationship 1 kg = 10³ g.
2.3 kg × (10³g/1 kg) = 2.3 × 10³ g
Step 3: Calculate the volume (V) of the Diesel sample
We will use the density formula.
ρ = m/V
V = m/ρ
V = 2.3 × 10³ g/(0.839 g/mL)
V = 2.7 × 10³ mL
Step 4: Convert "V" to L
We will use the relationship 1 L = 10³ mL.
2.7 × 10³ mL × (1 L / 10³ mL) = 2.7 L
Step 5: Convert "V" to gal
We will use the relationship 1 gal = 3.79 L.
2.7 L × (1 gal/3.79 L) = 0.71 gal
Answer:
2.3 kg x1000 g/kg = 2300 g
2300 g x 1 ml/0.839 g = 2741 ml
2741 ml x 1 L/1000 ml = 2.741 L
2.741 L x 1 gal/3.79 L = 0.72 gallons
Explanation:
Which pair of elements have chemical properties that are most similar
[tex]\text{Hello there! :)}[/tex]
Answer:
[tex]\large\boxed{(B)}[/tex]
Elements on the periodic table that are the closest in characteristics are in the same group, or column.
Looking at the answer choices, the only two pairs of elements that are in the same group are (B) Al and Ga, as well as (D) F and I.
On the periodic table, Al (Aluminum) and Ga (Gallium) are only one period (row) away from each other, while F (Flourine) and I (Iodine) are 3 periods away.
***Periods determine the number of energy levels and other properties, so elements that are closer to each other would have more similar properties.
Therefore, Aluminum and Gallium contain the most similar chemical properties.
If a boy was standing on his head, his mouth would be ___ to his nose.
Answer:
The correct answer is "inferior".
Explanation:
In anatomy, the term inferior is used to describe parts of the body that are below other part used as reference. Inferior comes from the Latin "inferus" that means "below". In this case, the mouth will always be inferior to the nose, it doesn't matter if the boy was standing on his head or if he is in other position.
Answer:
correct answer, inferior.
Explanation:
of little or less importance, value, or merit always felt inferior to his older brother. 2a : of low or lower degree or rank. b : of poor quality : mediocre. 3 : situated lower down : lower.
If one person is regarded as inferior to another, they are regarded as less important because they have less status or ability. He preferred the company of those who were intellectually inferior to himself.
Hope this helped!
BRAINLIEST PLEASE HELP WITH THIS CHEMISTRY QUESTION!!
Which of the following describes how further studies supported the work done by Ernest Rutherford?
Answer: James Chadwick discovered neutral particles in the nucleus. So your answer is C
Explanation:
I just took a pretest and I had this same question and I got it right
Answer:
James Chadwick discovered neutral particles in the nucleus.
Can you help me answer the question ?
A non-conservative force acting on a particle:_________.
A) does work that can depend on the path of motion.
B) does work equal to the change in the kinetic energy of the particle.
C) does work that is never equal to the change in kinetic energy of the particle.
D) can not have an associated potential energy function.
E) does work that only depends on the endpoints of the path, not on the path between the endpoints.
Answer: Option A.
does work that can depend on the path of motion.
Explanation:
A non-conservative force acting on a particle does work that can depend on the path of motion because a non conservative force is a type of force that can remove energy from a progressive system and this energy cannot be restored back and the forces are path dependent because it matters where the particle begin or end.
It is a type of force such as friction or air resistance. This type of force does work that only depend on the path of motion.
28 Which of the following equations does not represent a redox reaction?
A
B
с
D
2AgBr (s) → 2Ag (s) + Br2 (g)
Cu2+ (aq) + Zn (s) → Cu (s) + Zn2+ (aq)
2Fe (s) + 3Cl2 (9) ► 2FeCl3 (s)
MgO (s) + 2HCl (aq) → MgCl2 (aq) + H20 (1
Answer:
The answer is D. In the reactions A,B and C the reactants undergo changes in oxidation number. And also the reaction D is an acid_base neutralization reaction.
A change in the number of neutrons in an atom will change an isotope. What will happen when the number of protons changes in an atom?
3. The 2 in 1s2 represents the number of
located in that energy level.
Answers:
electrons
protons
Answer:
electrons
Explanation:
In an atom, you can have varying numbers of electrons, depending on if its an ion or not. You can use the orbitals to see the energy level of the atom.
An atom has only one number of protons. The number of protons cannot vary.
What is the solubility product expression for Zn3(PO4)2?
Answer:
[tex]Ksp=[Zn^{2+}]^3[PO_4^{3-}]^2[/tex]
Explanation:
Hello,
In this case, since the equilibrium dissociation of zinc phosphate is:
[tex]Zn_3(PO_4)_2(s)\rightleftharpoons 3Zn^{2+}(aq)+2(PO_4)^{3-}(aq)[/tex]
Due to the fact that only the zinc and phosphate ions are in aqueous state, the solubility product expression is written considering the law of mass action in which the concentration of each species is powered to the corresponding stoichiometric coefficient as follows:
[tex]Ksp=[Zn^{2+}]^3[PO_4^{3-}]^2[/tex]
Best regards.
7. What happen if we don't have water?
Answer:
our bodies will dehydrate causing us to die a dreadfully excruciating painful death
The solubility of sugar at 50°C is 260/100g water,and at 0°Cis 180g/100g water. What mass of sugar,will be deposited if 60g the saturated solution at 50°C is cooled to 0°C
Explanation:
27 °0 bc that how it is so this is the answer
What is a single covalent bond?
Answer: Single Covalent Bonds
Hydrogen and chlorine coming together is an example of a single covalent bond. Two hydrogen atoms will also come together to form a single covalent bond, as will two chlorine atoms. In these examples, each individual atom has just one unpaired electron to share with the other atom.
A Little Backstory I Guess: In chemistry, a single bond is a chemical bond between two atoms involving two valence electrons. That is, the atoms share one pair of electrons where the bond forms. Therefore, a single bond is a type of covalent bond.
sorry its so long :/ hope this even relatively helps...
Draw an important resonance form to show the delocalization of charge in the ion shown below.
Interactive 3D display mode
Answer:
Hello attached below is the missing ion diagram
Explanation:
Attached below is an important resonance form that shows the delocalization of charge in the ion shown
Please help me with this? :(
Answer:
1. Diagram C.
2. Diagram A.
Explanation:
1. Calcium atom, Ca has 20 protons and 20 electrons. On the other hand, Calcium ion, Ca^2+ has 20 protons and 18 electrons. This is true because the +2 charge on the calcium ion, Ca^2+ indicates that the calcium atom, Ca has loss 2 electrons.
From the above illustration we can say that calcium ion, Ca^2+ has the following:
Proton = 20
Electron = 18
Therefore, diagram C indicates calcium ion, Ca^2+.
2. Fluorine atom, F has 9 protons and 9 electrons. Fluoride ion, F¯ has 9 protons and 10 electrons. This is so because the –1 charge on the fluoride ion, F¯ indicates that the fluorine atom, F has gained 1 electron.
Thus, we can say that the fluoride ion, F¯ has the following:
Proton = 9
Electron = 10
Therefore, diagram A represent fluoride ion, F¯.
How does the number of valence electrons in atoms of metalloids explain why metalloids are semiconductors? They have one or two valence electrons, so they cannot lose electrons easily. They have one or two valence electrons, so they can lose or gain electrons. They have three to six valence electrons, so they cannot lose electrons easily. They have three to six valence electrons, so they can lose or gain electrons.
Answer:
They have three to six valence electrons, so they can lose or gain electrons.
Explanation:
Here, we are required to identify how the number of Valence electrons on atoms of metalloids explain why metalloids are semiconductors.
This is because; They have three to six valence electrons, so they can lose or gain electronsMetalloids are elements in the periodic table which are characterized by the the presence of 3 to 6 Valence electrons.
Metalloids unlike Alkali and alkali earth metals (which have 1 and 2 Valence electrons and are highly electropositive) and halogens( with valency of 7 and are highly electronegative) have three to six valence electrons and are therefore able to lose or accept electrons.Ultimately, the presence of three to six Valence electrons and the ability to either lose or gain electrons is the criteria for their semiconductor character.
Read more:
https://brainly.com/question/2708814
A. The measured pH of a 0.100 M HCl solution at 25 degrees Celsius is 1.092. From this information, calculate the activity coefficient of H+.B. The measured pH of a solution of 0.010 HCl and 0.090 KCl at 25 degree Celsius is 2.102. Calculate the activity coefficient of H+ in this solution.C. Why does the pH change in part B relative to that in part A?
Answer:
activity coefficient [tex]\mathbf{\gamma =0.809}[/tex]
activity coefficient [tex]\mathbf{\gamma = 0.791}[/tex]
The change in pH in part A = 0.092
The change in pH in part B = 0.102
Explanation:
From the given information:
pH of HCl solution = 1.092
Activity of the pH solution [a] = [tex]10^{-1.092}[/tex]
[a] = 0.0809 M
Recall that [a] = [tex]\gamma[/tex] × C
where;
[tex]\gamma[/tex] = activity coefficient
C = concentration
Making the activity coefficient the subject of the formula, we have:
[tex]\gamma = \dfrac{[a]}{C}[/tex]
[tex]\gamma = \dfrac{0.0809 \ M}{0.100 \ M}[/tex]
[tex]\mathbf{\gamma =0.809}[/tex]
B.
The pH of a solution of HCl and KCl = 2.102
[a] = [tex]10^{-2.102}[/tex]
[a] = 0.00791 M
activity coefficient [tex]\gamma = \dfrac{0.00791 \ M}{0.01 \ M}[/tex]
[tex]\mathbf{\gamma = 0.791}[/tex]
C. The change in pH in part A = 1.091 - 1.0 = 0.092
The change in pH in part B = 2.102 -2.00 = 0.102
Which option gives an object's volume in SF units?
O
A. 4.3 kg
B. 2.6 m3
C. 5.5 K
D, 3.4L
SUBMIT
Answer:
The correct answer is:
2.6 m3 (B)
Explanation:
SF unit stands for Stowage factor unit. Stowage factor is the volume occupied by one unit of mass (weight) when stowed in cargo space. SF expresses the unit in cubic meters (m³) or cubic feet. SF is a unit of measurement that indicates how much space (volume) a particular unit of cargo occupies in a ship's cargo compartment
Which of these is a chemical property?
boiling point
odor
ability to rust
color
Answer:
ability to rust
Explanation:
i'm like 90% sure thats correct
Solute and solvent in pasta
Answer:
It depends on what kind of pasta it is