Answer:
It is a chemical change.
Explanation:
When the electricity is off, the filament cools down to its original physical state. This physical process repeats every time the light is turned on and off. However, if the bulb is cracked and air is introduced, the oxygen in the air reacts with the tungsten filament which then undergoes a chemical change.
A laser pointer used in the classroom emits light at 5650 Å, at a power of 4.00 mW. (One watt is the SI unit of power, the measure of energy per unit of time. 1 W = 1 J/s). How many photons are emitted from the pointer in 115 seconds?
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 is the symbol for the element that has 12 protons,14 neutrons, and 12 electrons
Answer:
mg
Explanation:
can some one help The function of the cell wall in a plant cell is Question 2 options: Allowing material to pass in and out of the cell Uses carbon dioxide, water and energy from the sun to make sugar Breaks sugar down into ATP which the cell can use for energy Provides support and protection for the cell
Answer:
the protection one
Explanation:
the cell wall acts a barrier
the atomic mass of the isotope copper-__ is 62.930 amu
We have that The isotope of copper with the atomic mass of the isotope copper 62.930 amu is Cu 63
Cu 63
From the question we are told
the atomic mass of the isotope copper-__ is 62.930 amu
Generally
Copper is the 29th element of the the periodic table with an atomic mass of 29.
Copper as an elementt has 2 stable isotopes which are
Cu 63
Cu 65
Therefore
The isotope of copper with the atomic mass of the isotope copper 62.930 amu is Cu 63
For more information on this visit
https://brainly.com/question/17756498
what element has 3 protons 2 neutrons and 2 electrons
Answer:
helium i think
Explanation:
In a compound the elements are _____ together, whereas in a mixture the substances are blended together.
Answer:
bonded
Explanation:
Compounds are two elements bonded together.
A mixture is multiple substances blended together. The substances aren't bonded together and can easily be extracted from each other.
The nutrition label on rice lists the amounts of proteins, carbohydrates, and fats in one serving. These substances are important for human nutrition. How are proteins, carbohydrates, and fats related to the discipline of chemistry?
Answer:All are chemical compounds.
Some uses of titration in chem...
and definition of dipole moment
Answer:
Titration is used to determine the concentration of unknown solutions.
A dipole moments is a measurement of the separation of two opposite electrical charges
You bought a new car and estimated that your monthly payment would be $312. However, your actual payment amount is $325. How much error was in your estimate?
Choose the answer that shows the following number correctly
written in scientific notation.
430,000
a 4.3 x 104
b 43 x 104
C 0.43 x 106
d 4.3 x 105
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!
if volume stays the same, what happens to pressure?
Answer:
Pressure will stay the same if volume stays the same.
Answer:
Volume is inversely proportional to pressure, meaning if one goes up the other goes down and vise-versa. With volume remaining the same and there are no other given factors, pressure also remains the same
3.0 moles of nitrogen is reacted with 11.0 moles of hydrogen to produce ammonia according to the chemical equation shown below. Which one of the following statements is false?
N2(g) + 3 H2(g) → 2 NH3(g)
a. Hydrogen is the excess reactant.
b. 2.0 moles of hydrogen are left over.
c. 12.0 moles of ammonia are produced.
d. Nitrogen is the limiting reactant.
Answer:
c
Explanation:
From the equation, we can say that we need thrice the number of hydrogen than that of nitrogen
we are given 3 moles of nitrogen and 11 moles of hydrogen
but thrice the number of moles of nitrogen is 9, hence we have hydrogen in excess or Hydrogen is the excess reagent
Since we had 11 moles of Hydrogen and we only needed 9, 2 moles of hydrogen are left over
From the equation, we can see that the moles of ammonia formed will be twice the moles of nitrogen
Since 3 moles of nitrogen are used, the reaction will give us 6 moles of Ammonia and NOT 12 moles, therefore c is the correct answer
Since we have hydrogen in excess, our reaction is being limited because we have less Nitrogen, Hence Nitrogen is the Limiting Reagent
Option C is the only false statement
The false statement is that "12.0 moles of ammonia are produced"
According to the equation of reaction:
N₂ + 3H₂ >>>>> 2NH₃
1 mole of N₂ reacts with 3 moles of H₂
3 moles of N₂ will react with 9 moles of H₂
Since 3 moles of N₂ is said to react with 11 moles of H₂ (instead of 9 moles of H₂), H₂ is in excess by 2 moles. That is, N₂ is the limiting reactant.
Since N₂ is the limiting reactant:
1 mole of N₂ produces 2 moles of NH₃
3 moles of N₂ will produce 6 moles of NH₃
Therefore, we can conclude that:
Hydrogen is the excess reactant2.0 moles of hydrogen are left overNitrogen is the limiting reactantLearn more here: https://brainly.com/question/19555927
Which of the following pairs of elements are most likely to form an ionic bond?
A- Br and Ca
B- Br and N
C- Ca and Mg
D- Ca and Fe
Answer:
Ionic bonds ussally form with a metal, and a non metel elements, so the answer would most likley be B.
Explanation:
hope I could help
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¯.
When potassium chlorate decomposes to potassium chloride and oxygen gas is it a physical or chemical change?
1. How many ATOMS of carbon are present in 7.48 grams of carbon monoxide ?
Answer:
The answer is 1.61 × 10²³ atoms
Explanation:
To determine number of atoms, we will use the formula below
Number of atoms = number of moles (n) × avogadro's constant (6.02 x 10²³)
n was not provided, hence we will solve for n
n = mass/ molar mass
molar mass of carbon monoxide, CO (where C is 12 and O is 16) is 12 + 16 = 28
mass was provided in the question as 7.48
n = 7.48/28
n = 0.267
Hence,
number of atoms = 0.267 × 6.02 x 10²³
= 1.61 × 10²³ atoms
The first health care worker said, "Anatomy and Physiology makes the difference between me being a nurse and a ______ nurse?
Answer
The first health care worker said, "Anatomy and Physiology makes the difference between me being a nurse and a great nurse?
Explanation:
I got the correct answer
6. Un volumen de 1.0 mL de agua de mar contiene casi 4 x 10-12 g de Au. El volumen total de agua en los océanos es de 1.5 x 1021 L. Calcule la cantidad total de Au (en gramos) existente en los océanos y su valor total en dólares. ( 1 onza = $ 948)
Answer:
The total amount of Au is $ [tex]2.0\times10^{24}[/tex]
Explanation:
Given that,
Mass of 1.0 ml of Au [tex]m=4\times10^{-2}\ g[/tex]
Total volume of water in oceans [tex]V=1.5\times10^{21}\ L[/tex]
We need to calculate the volume in ml
Using given volume
[tex]V=1.5\times10^{21}\times1000\ mL[/tex]
[tex]V=1.5\times10^{24}\ mL[/tex]
We need to calculate the total mass of Au
Using given data
[tex]1\ ml\ volume = 4\times10^{-2}\ g[/tex]
[tex]1.5\times10^{24}\ ml=4\times10^{-2}\times1.5\times10^{24}[/tex]
So, The total mass of Au is [tex]6\times10^{22}\ g[/tex]
The mass will be in ounce,
[tex]Mass=0.035274\times6\times10^{22}[/tex]
[tex]Mass=2.12\times10^{21}\ ounce[/tex]
The total amount of the Au Will be
[tex]Total\ amount=2.12\times10^{21}\times948[/tex]
[tex]Total\ amount=2.0\times10^{24}[/tex]
Hence, The total amount of Au is $ [tex]2.0\times10^{24}[/tex]
explain why division by zero is undefined
Answer:
Division by zero is undefined because there is no other number to divide it by.
Explanation:
Unlike 2/2, 2/0 doesn't have anything to divide the 2 by which makes it undefined and impossible to solve.
The division by zero is undefined, because whatever response we may give, we will then have to concur that the answer times 0 = 1, which is illogical because anything multiplied by zero is zero.
Why division by zero is undefined ?Since any attempt at definition results in a contradiction, the outcome of a division by zero cannot be defined. a=r*b. r*0=a. (1) (1) But because r*0=0 for all r, there is no solution to the equation unless a=0 (1).
Again, mathematicians have left zero divided by zero as an open problem because they are both equally valid and, to be honest, neither of them is consistent with the rest of mathematics.
Mathematically, it is impossible to divide a number by zero, just as in this illustration. Or, at the very least, there isn't currently a means to do that. Numerous attempts have been made to figure out how to divide by zero, as mathematicians are constantly looking for solutions to intriguing mathematical issues.
Thus, The division by zero is undefined, because whatever response we may give, we will then have to concur that the answer times 0 = 1.
To learn more about division by zero is undefined, follow the link;
https://brainly.com/question/11523699
#SPJ2
Identify the type of chemical reaction taking place in the following and write in balanced equation from
a) Barium Chloride mixed with copper sulphate solution and a white precipitate is observed b) On heating green colour sirf ferrous sulphate crystals reddish brown solid left and smell of gas having order of burning sulphur is produced.
Answer:
a. The balanced chemical equation is written below and this is a type of double displacement reaction.
Explanation:
When barium chloride reacts with copper sulfate, a white precipitate of barium sulfate is observed.
The chemical equation for the reaction of barium chloride and copper sulfate follows:
b.
2FeSO4--(heat)---> Fe2O3 + SO2+ SO3
This Reaction is an example of Thermal Decomposition Reaction.
You have a piece of gold jewelry weighing 9.35g. Its volume is 0.654cm 3 . Assume the metal is an alloy of gold and silver, which have densities of 19.3g/cm 3 and 10.5g/cm 3 , respectively. Also assume that there is no change in volume when the pure metals are mixed. Calculate the percentage of gold (by mass) in the alloy.
Answer:
57.54% is the percentage of gold by mass in the alloy.
Explanation:
The mass of the mixture is 9.35g. That is:
9.35g = Mass Gold + Mass Silver
Mass silver = 9.35g - Mass gold (1)
Now, the volume of the jewelry is the sum of volumes of gold and silver:
0.654cm³ = Mass Gold / 19.5g/cm³ + Mass silver / 10.5g/cm³ (2)
Volume = Mass / Density.
Replacing (1) in (2):
0.654cm³ = Mass Gold / 19.5g/cm³ + (9.35g - Mass gold) / 10.5g/cm³
0.654 = 0.051282 Mass Gold + 0.890476 - 0.095238 Mass gold
-0.236476 = -0.043956 Mass gold
Mass gold = 5.38g
And mass percent of gold in the alloy is:
5.38g / 9.35g * 100 =
57.54%Select the answer from the drop-down, ranging from true or false.
Mixtures have components that are always in fixed ratios.
[ true or false ]
Compounds can only be separated physically.
[ true or false ]
The components of a mixture keep their unique properties.
[ true or false ]
Mixtures can be physically separated
[ true or false ]
Mixtures are pure substances
[ true or false ]
Compounds are pure substances
[ true or false ]
Answer:
False, False, True, True, False, True
Explanation:
Mixtures have components that are always in fixed ratios. FALSE. The ratio of components in a mixture is variableCompounds can only be separated physically. FALSE. Compounds can only be separated chemically.The components of a mixture keep their unique properties. TRUE. Mixtures can be physically separated. TRUE. Mixtures are pure substances. FALSE. Mixtures are formed by a mixture of 2 or more pure substances, not bonded chemically.Compounds are pure substances. TRUE.true? no false. ... no its true uhhhhh no gotta be false true. false. true. fase. gotta be tru false or maybe its true? nah its false
pls brainliest?
Pb-214 in beta decay
Lead 214 emits then beta electrons to transform into bismuth 214 and polonium 214, which produces lead 210 through the emission of a third alpha particle. This series of transformations take place in a time span roughly equal to an hour.
Hope this helps, if I am right, brainliest? :))))
An example of an extensive physical property is
Group of answer choices
mass
density
boiling point
melting point
Answer:
boiling point
state raw material of wood charcoal and coke,lampblack
Answer:
its a tree becoz charcoal came from wood
Describe each highlighted bond in terms of the overlap of atomic orbitals. (If the highlighted bond is not a pi bond, select the blank option from the dropdown menu.) Compound 1: Molecular orbital type: _________ Atomic orbitals in the sigma bond: _________ Atomic orbitals in the pi bond: _________ Compound 2: Molecular orbital type: _________ Atomic orbitals in the sigma bond: _________ Atomic orbitals in the pi bond: _________
The image of the bonds are missing, so i have attached it.
Answer:
A) - Sigma bond
-Sp³ and Sp³
- None
B) - Sigma and pi bond
- Sp² of C and p of O
- p of C and P of O
Explanation:
A) For compound 1;
- the molecular orbital type is sigma bond due to the end-to-end overlapping.
- Atomic orbitals in the sigma bond will be Sp³ and Sp³
- Atomic orbitals in the pi bond would be nil because there is no pi bond.
B) For compound 2;
- the molecular orbital type is sigma and pi bond
-Atomic orbitals in the sigma bond would be Sp² of C and p of O
- The Atomic orbitals in the pi bond will be; p of C and p of O
Catie set a glass of hot water and a glass of cold water on the kitchen table and let them sit for one hour. How will the particle motion within the glasses change?A.The particles in both glasses will speed up.B.The particles in both glasses will slow down.C.The particles in the hot water will slow down, while the particles in the cold water will speed up.D.The particles in the hot water will speed up, while the particles in the cold water will slow down.
Answer:
C.The particles in the hot water will slow down, while the particles in the cold water will speed up
Explanation:
Heat causes changes in the molecules of substances when applied to them. The molecules of water, as a case study used in this question, when heated has an increased kinetic energy which causes its particles to move faster i.e. speed up. Also, when water is freezed or cold, it's particles move slower i.e. slow down due to decreased kinetic energy.
Hence, when a hot glass of water and a cold glass of water are placed on a kitchen table for 1 hour, they don't remain in their respective thermal state.
- The hot water (with an increased movement of molecules) begin to cool down, hence, its particles slows down as it gets cold or less hot.
- Likewise, the cold water (with a decreased movement of molecules) begins to get warmer, hence, it particles speedens up as it gets warmer.
Therefore, The particles in the hot water will slow down, while the particles in the cold water will speed up
The density of water at 40°C is 0.992 g/mL. What is the volume of 2.69 g of water at this temperature? V= mL
Answer:
[tex]\boxed {\tt 2.71169355 \ mL}[/tex]
Explanation:
Density can be found using the following formula:
[tex]d=\frac {m}{v}[/tex]
Rearrange the formula for v. Multiply both sides by v, then divide both sides by d.
[tex]d*v =\frac {m}{v}*v[/tex]
[tex]d*v=m[/tex]
[tex]\frac{d*v}{d}=\frac{m}{d}[/tex]
[tex]v=\frac{m}{d}[/tex]
The volume can be found by dividing the mass by the density. The mass is 2.69 grams and the density is 0.992 grams per milliliter.
[tex]m= 2.69 \ g\\d= 0.992 \ g/mL[/tex]
Substitute the values into the formula.
[tex]v=\frac{2.69 \ g}{0.992 \ g/mL}[/tex]
Divide. Note that the grams, or g, will cancel each other out.
[tex]v=\frac{2.69}{0.992 \ mL}[/tex]
[tex]v= 2.71169355 \ mL[/tex]
The volume of the water is 2.71169355 milliliters.
I am timed please help
Answer:
compound
Explanation:
MgO is an inorganic compund :) The simplest explanation is that it's not an element b/c there's two elements (Mg & O) in the substance, and it's not a mixture b/c you can't easily separate the two elements.
Answer:
magnesium when magnesium is burnt by heat it forms an compound called magnesium oxide