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.
Which of the reactions are spontaneous (favorable)?
A. 2Mg(s) + O2(g) rightarrow 2MgO (s) delta G = - 1137 kJ / mol
B. NH3(g) + HCl(g ) rightarrow NH4Cl(s) delta G = - 91.1 kJ / mol
C. AgCl(s) rightarrow Ag+ (aq) + Cl-[aq) delta G = 55.6 kJ / mol
D. 2H2(g) + O2(g) rightarrow 2H2O(g) delta G= 456 kJ / mol
E. C(s) + H2O(t) rightarrow CO(g) + H2(g) delta G = 90.8 kJ / mol
F. CH4(g) + 2O2(g) rightarrow CO2(g) + 2H2O(t) delta G = -820 kJ / mol
A. Reaction A.
B. Reaction B.
C. Reaction C.
D. Reaction D.
E. Reaction E.
F. Reaction F.
Answer: Reactions: A, B and F
Explanation: Gibbs Free Energy, symbol G, combines Enthalpy (sum of internal energy) and Entropy (measure of how much the energy of atoms and molecules become spread out in a process).
The change in free energy (ΔG) is the sum of enthalpy and the product of temperature and entropy of the system.
With free energy, it is possible to determine if a reaction is spontaneous, i.e., happens wthout external energy, or non-spontaneous.
If ΔG is negative, reaction is spontaneous. If ΔG is positive, reaction is non-spontaneous.
Analysing each ΔG of the reactions above, reactions A, B and F's Gibbs Free energy are negative, so these 3 are spontaneous.
Be sure to answer all parts. Calculate the mass of each product formed when 70.76 g of diborane (B2H6) reacts with excess water: B2H6(g) + H2O(l) → H3BO3(s) + H2(g) [unbalanced] Mass of H3BO3: g Mass of H2: g
Answer:
A. 313.37 g of H3BO3.
B. 30.33 g of H2.
Explanation:
We'll begin by writing a balanced equation for the reaction. This is given below:
B2H6 + 6H2O → 2H3BO3 + 6H2
Next, we shall determine the mass of B2H6 that reacted and the masses of H3BO3 and H2 produced from the balanced equation equation. This can be obtained as follow:
Molar mass of B2H6 = (2×11) + (1×6) = 22 + 6 = 28 g/mol
Mass of B2H6 from the balanced equation = 1 × 28 = 28 g
Molar mass of H3BO3 = (1×3) + 11 + (3×16) = 3 + 11 + 48 = 62 g/mol
Mass of H3BO3 from the balanced equation = 2 × 62 = 124 g
Molar mass of H2 = 2×1 = 2 g/mol
Mass of H2 from the balanced equation = 6 × 2 = 12 g
From the balanced equation above:
28 g of B2H6 reacted to produce 124 g of H3BO3 and 12 g of H2.
A. Determination of the mass of H3BO3 produced from the reaction.
This can be obtained as follow:
From the balanced equation above,
28 g of B2H6 reacted to produce 124 g of H3BO3.
Therefore, 70.76 g of B2H6 will react to produce = (70.76 × 124)/28 = 313.37 g of H3BO3.
Therefore, 313.37 g of H3BO3 were obtained from the reaction.
B. Determination of the mass of H2 produced from the reaction.
This can be obtained as follow:
From the balanced equation above,
28 g of B2H6 reacted to produce 12 g of H2.
Therefore, 70.76 g of B2H6 will react to produce = ((70.76 × 12)/28 = 30.33 g of H2.
Therefore, 30.33 g of H2 were obtained from the reaction.
Is matter smooth and continuous?
Answer:
YES,Explanation:
Matter is smooth and continuous. ... A liquid has a definite volume; but it has no definite shape.12.A piece of magnesium is in the shape of a cylinder with a height of 5.62 cm
and a diameter of 1.34 cm. If the magnesium sample has a mass of 14.1 g, what
is the density of the sample?
Answer:
Density, d = 1.779 g/cm³
Explanation:
The density of a material is given by its mass per unit volume.
Here, height of a piece of magnesium cylinder, h = 5.62 cm
Its diameter, d = 1.34 cm
Radius = 0.67 cm
Volume of he cylinder,
[tex]V=\pi r^2 h\\\\\text{Putting the value of r and h, we get :}\\\\V=(\pi \times (0.67)^2\times 5.62)\ cm^3[/tex]
[tex]d=\dfrac{m}{V}\\\\d=\dfrac{14.1\ g}{(\pi \times (0.67)^2\times 5.62)\ cm^3}\\\\d=1.779\ g/cm^3[/tex]
So, the density of the sample is 1.779 g/cm³.
What is an example of a physical change?
A. having less ash than the paper that was burned to form it
B. ice forming and then melting back into water
C. rust having a different identity than the iron it forms on
D. the irreversible reaction of vinegar and baking soda
What one would you guys choose?
Answer:
B is correct answer
Explanation:
Answer:
B.
Explanation:
How many cm are in 29.7km?
Answer:
there are 2970000cm in 29.7km
Explanation:
Can someone please help me with this? :(
Answer:
Bo
Explanation:
Bo is not a element
A peregrine falcon dives 176 meters through the air in 8 seconds. Its
average speed during the dive is 22 m/s. *
Answer:
This question is asking to find the average speed during the dive. The answer is 22m/s.
Explanation:
Average speed of a substance can be calculated knowing it's distance over a particular amount of time.
The formula for average speed is:
Average speed (s) = Distance (d) / time (t)
In the case of this question where A peregrine falcon dives 176 meters through the air in 8 seconds, the distance of the falcon is 176m, while the time is 8s. Hence;
Average speed = 176/8
Average speed = 22
Therefore, the average speed of the falcon diver is 22m/s.
An element has a mass number of 9 and 5 neutrons. What element is it?
Answer:
Fluorine
Fluorine is the element in question, as its atomic number is 9 . You would name this particular isotope using the mass number. It would be called fluorine-19.
Explanation:
Answer:
Fluorine
Fluorine is the element in question, as its atomic number is 9 . You would name this particular isotope using the mass number. It would be called fluorine-19.
What is the mass of 87.94 mL of ethanol, which has a density of 0.79 g/mL?
Answer:
The answer is
69.47 gExplanation:
The mass of a substance when given the density and volume can be found by using the formula
mass = Density × volumeFrom the question
volume of ethanol = 87.94 mL
density = 0.79 g/mL
The mass of ethanol is
mass = 87.94 × 0.79
mass = 69.4726
We have the final answer as
69.47 gHope this helps you
An atomic model shows 19 protons, 20 neutrons, and 19 electrons. What is the mass number of the atom?
The particles of a gas inside a balloon are experiencing an increase in their average kinetic energy and the number of collisions with the wall of the balloon. What is the most likely outcome? higher gas pressure inside the balloon higher air pressure outside the balloon a decrease in gas temperature inside the balloon a large increase in air temperature outside the balloon
The higher Gas pressure inside the balloon. Hence, option A is correct.
How is kinetic energy related to temperature?In a molecule, the kinetic energy existing is "directly proportional" to the temperature of the molecule. If one of the values increases, then the other value also increases and vice-versa.
The higher Gas pressure inside the balloon. As the number of collisions with the wall of the balloon increases, the pressure inside increases.
Hence, option A is correct.
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I have a buddy who recycles electronics, and isolates metals from the connector pins electrical boards. He isolates gold, for example, and purifies it the best he can, then sells it along with his other scrap metal. This last go around he was able to isolate 3.00 g of Au with a process he claims results in a 80.0% yield. If he is correct, what was his theoretical yield
Answer:
Theoretical yield = 3.75g
Explanation:
Percent yield is defined as one hundred times the ratio between actual yield and theoretical yield. The expression is:
Percent yield = Actual Yield / Theoretical Yield * 100
In the problem, your actual yield was 3-00g.
Percent yield is 80.0%.
Solving for theoretical yield:
80% = 3.00g / Theoretical yield * 100
Theoretical yield = 3.00g / 80.0% * 100
Theoretical yield = 3.75gThe density of ice is 0.917 g/cm3. What volume of ice does 52.75 g occupy?
Answer:
The answer is
57.52 mLExplanation:
The volume of a substance when given the density and mass can be found by using the formula
[tex]volume = \frac{mass}{density} [/tex]
From the question
mass of ice = 52.75 g
density = 0.917 g/cm³
The volume of the ice is
[tex]volume = \frac{52.75}{0.917} \\ = 57.52453653[/tex]
We have the final answer as
57.52 mLHope this helps you
Complete hydrolysis of a hexapeptide gives 2 Gly, Leu, Phe, Pro, and Tyr. Reaction of the peptide with phenylisothiocyanate gave the phenylthiohydantoin of Pro. Partial hydrolysis of the peptide gave the following fragments: Phe-Gly-Tyr, Gly-Phe-Gly, Pro-Leu-Gly, Leu-Gly-Phe. What is the structure of the peptide
Answer:
The complete sequence : Pro-Leu-Gly-Phe-Gly-Tyr
Explanation:
For the formation of phenylisothiocyanate, the four peptide sequences overlap common residue to get the the complete sequence of the hexapeptide as shown in the diagram attached below
Attached below is the structure of the peptide
i am timed please help
Answer:
mixture
Explanation:
there was leftover components meaning there was something mixed into the liquid
Calculate the percent composition for each of the elements in Na3PO4. A 5.00 gram sample of an oxide of lead PbxOy contains 4.33 g of lead. Determine the simplest formula for the compound. Balance the following equations by inspection: Cu(N03)2 rightarrow CuO + NO2 + O2 C2H6 + O2 rightarrow CO2 + H2O Mg3N2 + H2O rightarrow Mg(OH)2 + NH3 Magnesium (Mg) reacts with chlorine gas (C12) to produce magnesium chloride (MgC12). How many grams of Mg will react with 2 moles of Cl2? Mg(s) + C12(g) rightarrow MgC12(s) The compound P4S3 is used in matches. It reacts with oxygen to produce P4O10 and SO2. The unbalanced chemical equation is shown below, P4S3(s) + O2(g) rightarrow P4O10(s) + SO2(g) What mass of SO2 is produced from the combustion of 0.331 g P4S3 in excess O2? Nitric oxide is made from the oxidation of ammonia. What mass of nitric oxide can be made from the reaction of 8.00 g NH3 with 17.0 g O2? 4 NH3(g) + 5 O2(g) rightarrow 4 NO(g) + 6 H2O(g) To what volume should you dilute 50.0 mL of 12 M HNO3 solution to obtain a 0.100 M HNO3 solution?
Answer:
1. Percentage composition of: Na = 42%; P = 19.0%; O = 39%
2. Simplest formula of compound is PbO₂
3. (i) 2Cu(NO₃) ---> 2CuO + 2NO₂ + 3O₂
(ii) 2C₂H₆ + 7O₂ ---> 4CO₂ + 6H₂O
(iii) Mg₃N₂ + 6H₂O ---> 3Mg(OH)₂ + 2NH₃
4. 48 g of MG will react with 2 moles of Cl₂
5. 0.288 g of SO2 will be produced from the combustion of 0.331 g P₄S₃ in excess O₂
6. 12.8 g of nitric oxide can be produced from the reaction of 8.00 g NH₃ with 17.0 g O₂
7. The stock acid solution should be diluted to 6000 mL or 6.0 L
Explanation:
The full explanation is found in the attachments below
Metal atoms always form a cation of a single, specific charge.
a.) True, because metal atoms form ionic compounds of a known composition.
b.) False, because some metal atoms are known to have more than one possible positive charge.
c.) True, because nonmetal atoms always form anions of a single, specific charge.
d.) True, because metal atoms lose all of their valence electrons.
e.) False, because elements in different rows of the periodic table can form different cations.
Answer:
c.) true, because nonmetal atoms always form anions of a single , specific charge
Chlorine could combine with _ to gain the extra electron it needs to stabilize its outer shell
outer shell.
A. helium
B. sulfur
C. hydrogen
D. none of these
Answer:
C, hydrogen.
Explanation:
Which of the alkyne addition reactions below involve(s) an enol intermediate?
1) halogenation.
2) hydrogen in the presence of a metal catalyst.
3) hydroboration/oxidation.
4) none of the above.
The correct answer is (3): hydroboration/oxidation.
Hydroboration/oxidation of alkynes involve an enol intermediate.
An intermediate is a specie that occurs along the steps of a non-elementary reaction but does not appear among the products.
Hydroboration refers to the reaction of borane (BH3) with alkyne. The addition of borane to an alkyne passes through an enol intermediae and the same also goes for oxidation of an alkyne.
Hence, hydroboration/oxidation are alkyne addition reactions that involve enol intermediate. The mechanism of hydroboration is shown in the image attached.
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A ratio that compares the length and width of a garden is what type of model?
A. Physical
B. Conceptual
C. Computer
D. Mathematical
Answer:
D. Mathematical
Explanation:
Where did I go wrong? I know the 2.58 is the right answer but where did I go wrong in my work? Please help!!
Answer: See below
Explanation:
In this problem, conversion factors are very important. In the second conversion, you wrote 1 kg=0.001 g. This is incorrect. It should be 1 kg=1000g. Otherwise, the rest is correct. Make sure to have correct conversions. The answer will be correct.
Draw the line-bond structure of oleic acid (cis-9-octadecenoic acid), CH3(CH2)7CH=CH(CH2)7COOH, at physiological pH. You do not need to draw hydrogen atoms attached to carbon atoms.
Answer:
Explanation:
Oleic acid originates from an unsaturated fatty acid with 18 carbon atoms and one double bond, which can be found in olive oil and many other vegetable and animal oils and fats. Its economic importance includes the production of soap making and cosmetics etc.
The line-bond structure of the given oleic acid in the question can be found in the attached below.
The line-bond structure of oleic acid is given in the image attached. The line-bond structure represents the number of carbon atoms.
Oleic acid:Oleic acid is an omega-9 fatty acid. It can be made by the body. It is also found in foods. Highest levels are found in olive oil and other edible oils. Oleic acid is most commonly used for preventing heart disease and reducing cholesterol. It is long chain of 18 Carbon atoms.
It is found in oils such as olive, palm, peanut, and sunflower.
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Solve: (6.825 x 10-3) (1.2 x 10-8)
Choose the answer with the correct number of significant figures.
a 8.2 x 10-11
b 0.081 x 10-8
C 8.01 x 1011
d None of the above
Answer: a.) 8.2 x 10^-11
Explanation:
6.300x10-5 – 7.200x10-3
Answer:
-17
Explanation:
6300/1000×10-5-7200/1000×10-3
63000/1000-5-72000/1000-3
63-5-72-3
-17
the coefficient is -7.137 but i’m not sure what the exponent is, i’m sorry :/
Which wave has the greatest distance from trough to trough?
Answer:
C.C
Explanation:
Just took the test
A transverse wave is a motion in which all points on a wave oscillate along paths at right angles. Hence, option C is correct.
On a wave, what is the distance from trough to trough?The wavelength is the horizontal distance between two adjacent crests or troughs.
The longest distance a particle goes from rest is to the peak of a crest or the bottom of a trough in a transverse wave. The amplitude of a transverse wave is this distance.
Hence, option C is correct.
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What determines the reactivity of an akali metal?
Answer:
The number of valence electrons determines an element's reactivity, or how likely the element is to react with other elements.
Explanation:
I am timed please help!!
Answer:
it is a mixture
element are pure and compound are formed in a fixed ratio
Explanation:
An object is a regular, rectangular, solid with dimensions of 2 cm by 3cm by 2cm. It has a
mass of 24 g. Find its density.
Answer:
2
Explanation:
Density = mass/volume
m=24
v=2*3*2=12
24/12=2
Answer:
[tex]\boxed {\tt d= 2 \ g/cm^3}[/tex]
Explanation:
Density can be found using the following formula.
[tex]d=\frac{m}{v}[/tex]
where [tex]m[/tex] is the mass and [tex]v[/tex] is the volume.
We know the mass is 24 grams. We must find the volume.
Since it is a rectangle, the volume can be found using the following formula.
[tex]v=l*w*h[/tex]
The length is 2 centimeters, the width is 3 centimeters and the height is 2 centimeters.
[tex]v= 2 \ cm * 3 \ cm * 2\ cm[/tex]
[tex]v= 6 \ cm^2 * 2\ cm[/tex]
[tex]v= 12 \ cm^3[/tex]
Now we know the volume, and can substitute it into the density formula.
[tex]d=\frac{m}{v}[/tex]
[tex]m= 24 \ g\\v= 12 \ cm^3[/tex]
[tex]d=\frac{24 \ g}{12 \ cm^3}[/tex]
[tex]d= 2 \ g/cm^3[/tex]
The density is 2 grams per cubic centimeter.
Sample of carbonate rock is a mixture of CaCO3 and MgCO3. The rock is Analyzed in a laboratory and the results are recorded in the table above. Which columns in a table provide all the information necessary to determine the mole ratio of analyzed in a laboratory and the results are recorded in the table above. Which columns in a table provide all the information necessary to determine the mole ratio of Ca to Mg in the rock
Answer:
You need the mass of Mg and Ca in the sample and their molar masses
Explanation:
Its the only answer that made sense because using those 4, can give you their ration
The Columns in the table that provides the information necessary for the calculating the mole ratio of Ca to Mg are columns ; 3, 4, 6, and 7
Although some data related to your question is missing attached below is the missing data
Determining the mole ratio of Ca to Mg
Ca : Mg
mass of Ca / molar mass : mass of Mg / Molar mass
( 36.1 / 40.1 ) : ( 2.4 / 24.3 )
9.14 : 1
∴ The mole ratio of Mg to Ca
≈ 1 : 9
Where: Column 3 = Mass of Mg in the sample ( g )
Column 4 = mass of Ca in the sample ( g )
Column 6 = Molar mass of Mg ( g/mol )
Column 7 = molar mass of Ca ( g/mol )
Hence the Mole ratio of Mg to Ca = 1 : 9
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