Answer: The energy of a photon with a wavelength of 820 nm is [tex]2.42 \times 10^{-19} m[/tex].
Explanation:
Given : Wavelength = 820 nm
Convert nm into meter as follows.
[tex]1 nm = 10^{-9}\\So, 820 nm = 820 nm \times \frac{10^{-9} nm}{1 nm}\\= 820 \times 10^{-9} m[/tex]
The relation between energy and wavelength is as follows.
[tex]E = \frac{hc}{\lambda}[/tex]
where,
E = energy
h = Planck's constant = [tex]6.63 \times 10^{-34} kg m^{2}/s[/tex]
c = speed of light = [tex]3.0 \times 10^{8} m/s[/tex]
[tex]\lambda[/tex] = wavelength
Substitute the values into above formula as follows.
[tex]E = \frac{hc}{\lambda}\\= \frac{6.63 \times 10^{-34} kg m^{2}/s \times 3.0 \times 10^{8} m/s}{820 \times 10^{-9} m}\\= \frac{1.989 \times 10^{-25}}{820 \times 10^{-9}}\\= 2.42 \times 10^{-19} m[/tex]
Thus, we can conclude that energy of a photon with a wavelength of 820 nm is [tex]2.42 \times 10^{-19} m[/tex].
Mrs. Franklin decides to use her new aluminum pan to scramble eggs. She wants to determine how much heat energy will be needed to
heat her aluminum pan from 20 degrees celsius to 220 degrees celsius. She obtains the specific heat of aluminum from the reference
table. It lists the specific heat of aluminum as 0.90 N/kg*degrees celsius. The pan has a mass of 0.5 kg. She does the calculation
correctly. Which one of the following is her answer?
Your answer:
0.45 joules of heat energy
O 0.9 kilojoules of heat energy
O 90 kilojoules of heat energy
180 joules of heat energy
Answer:
90 kilojoules of heat energy
Explanation:
I don't really know why this is just the answer to it on my quiz so if someone else can explain.
help please
According to the data what kind of substance is gastric juice?
A.
it is a weak acid since the blue litmus paper turns red and the pH is 1.7
B.
it is a strong base since the blue litmus paper turns red and the pH is 1.7
C.
it is a strong acid since the blue litmus paper turns red and the pH is 1.7
D.
it is a weak base since the blue litmus paper turns red and the pH is 1.7
Answer:
C. it is a strong acid since the blue litmus paper turns red and the pH is 1.7Explanation:
As per table gastric juice has pH of 1.7 which is the strong acid. If you remember, 0-7 range determines acids and litmus paper confirms that by turning red.
So correct choice is C.
9) What is the density of the gold rock with a mass of 386 grams and has a volume of 20 cubic centimeters?
O 0.193 g/cc
O 193 g/cc
O 1.93 g/cc
19.3 g/cc
Answer:
density= mass/volume
hence density of gold rock
= 386/20
=19.3 g/cc
What is the molecular geometry of a molecule with 4 outer atoms and 2 lone pairs on the central atom?
Answer:
See explanation
Explanation:
The valence shell electron pair repulsion theory holds that the number of electron pairs on the outermost shell of the central atom in a molecule determines the shape of the molecule.
In accordance with this theory, the electron domain geometry of a molecule having 4 outer atoms and 2 lone pairs on the central atom is based on an octahedron. The molecular geometry of this molecule is square planar with a bond angle of 90 degrees.
Convert 500.0 mL at 740.0 mm of Hg to its new volume at 780.0 mmHg. 474.4mL
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Hiiii- Are you asking what the element of Hu is???
If so- it's Hundium.
...
If this was just a random keyboard spam of a question, then Huuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuu to you too
How many boron (B) and sulfur (S) atoms are in B253?
Answer:
2 boron and 3 sulfur
Explanation:
The subscript/ number behind and under is a subscript this tells you how many atoms there are
PLEASE HELP ME OUT. I AM REALLY LOST AND I JUST NEED THIS LAST QUESTION I WILL BE GRATEFUL AND WILL GIVE BRANLIEST!
PLEASE HELP ME OUT. I AM REALLY LOST AND I JUST NEED THIS LAST QUESTION I WILL BE GRATEFUL AND WILL GIVE BRANLIEST!
Explanation:
—COOH and —NH₂
Carboxylic Acid and Amino group
-TheUnknownScientist
How many grams of H2O is created from 60 grams of O2?
[2 H2 + O2 —> 2 H2O]
Answer:
67.5 gm H2O
Explanation:
2 H2 = 4 gm
O2 = 32 gm
2 H20 = 36 gm
so 32 gm O2 results in 36 gm H20
32/36 = 60/x x = 67.5 gm
Is NaCl solute or water ?
Commercially available concentrated hydrochloric acid is 37.0% w/w HCl. Its density is 1.18g/ml. Calculate the molarity of concentrated HCl?
Answer:
M = 12.0M
Explanation:
Hello there!
In this case, according to the given by-mass percent of HCl, which can be set up in terms of mass of HCl over mass of solution, we can calculate the molarity, by multiplying by the density to get the mL's of solution and further convert to liters. Moreover, the molar mass of HCl (36.46 g/mol) must be also used to calculate the moles, since molar units requires moles of solute and liters of solution as shown below:
[tex]M=\frac{37.0gHCl}{100g\ sln}*\frac{1.18g\ sln}{1mL\ sln}*\frac{1000mL\ sln}{1L \ sln}*\frac{1molHCl}{36.46gHCl}\\\\M= 12.0M[/tex]
Best regards!
Can someone explain the steps for balancing chemical equations in depth?
Answer:
Steps explained below
Explanation:
To explain balancing of chemical equations, I will make use of an example equation where Hydrogen and oxygen react to form water.
H2 + O2 = H2O
Now, the equation I've listed above is an unbalanced chemical equation. It can be balanced by the following steps;
Step 1: Identify the elements on both the left Hand side and the right hand side.
In this case;
on the left hand side, we have H and O.
On the right hand side, we have H and I also.
Step 2: Identify the number of atoms of each element on both the left and right hand sides.
On the left, H has 2 atoms and O has 2 atoms.
On the right, H has 2 atoms and O has 1 atom.
Step 3: For the equation to be balanced, the number of atoms of each element on the right and left hand side must be the same.
Thus,
O on the left hand side has 2 atoms but on the right hand side it has 1 atom. Thus, we will multiply O on the right by 2 to balance what we have on the left.
So, we now have;
H2 + O2 = 2H2O
Step 4: Check equation: We now have;
H2 + O2 = 2H2O
Our left hand side remains 2 atoms of H and 2 atoms of O. But on the right, we now have;
2 atoms O and 4 atoms of H.
Which means atoms of H is not balanced with the left side.
Step 5: rebalance equation: To rebalance, we multiply H on the left by 2 to give us 2 × 2 = 4 atoms.
Thus, we now have;
2H2 + O2 = 2H2O
Answer:
Representation of chemical reactivity by symbols follows two absolute rules:
Explanation:
1
.
Mass is conserved.
2
.
Charge is conserved.
What do we mean by this? If we start with 10 g of reactant FROM ALL SOURCES, AT MOST we can get 10 g of product; and in practice we are not even going to get that. Since mass is a fundamental property of atoms and molecules it follows that atoms and molecules are conserved in EVERY chemical reaction.
)
Because it is not balanced (why not?), we can reject it out of hand, because we know that it does not reflect reality.
)
80 g of reactant gives 80 g of product
...charge and mass are balanced here. And so this is a reasonable representation of reality.
I know I am being absolute when I say that charge and mass are conserved, but this reflects EVERY CHEMICAL REACTION, EVERY EXPERIMENT EVER PERFORMED: when a reaction is studied in detail,
garbage out has always equalled garbage in.
And how do we know that masses are conserved; that stoichiometry operates? How else but by experiment? How else but by extensive and quantitative study of particular chemical reactions?
Every chemical reaction ever performed (and as far we know, TO BE PERFORMED), displays conservation of mass. And today we have a particle view of chemical reactivity, and our ideas, developed over only some 200-300 years, insist that matter is conserved. That molecules and atoms themselves have discrete masses, which are certainly measurable, supports our notion of conservation of mass.
This idea can be extended to the representation of redox reactions, where we can invoke the electron as a charged particle that is exchanged between species in a redox process. Charge is conserved, as well as mass.
If this all seems a lot to take in, remember you will only be asked to balance equations to which you have already been introduced. Alkanes combust in air to give carbon dioxide and water, iron combines with oxygen to give rust,
If you can write a chemical equation that balances mass and charge, you have proposed a reasonable chemical pathway. See here for redox equations.
Explanation:
Science help due by 11:59 What is gravity like on other planets
compared to Earth?
Explanation:
Mercury 0.377 g
Venus 0.905 g
Earth 1 g (midlatitudes)
Moon 0 .165 7 g (average)
. If 30.0 grams of copper (II) chloride reacts with 40.0 grams of sodium nitrate, what is the limiting reactant?
Answer:
The limiting reactant is copper (II) chloride
Explanation:
here you go
What event occurs when the
tension built up along Earth's
plates is released causing one
plate to slip past another?
Answer:
An earthquake
Explanation:
6. How are these two isotopes of carbon different from each other? 12C and 14C
Answer:
Carbon-12 and carbon-14 are two isotopes of the element carbon. The difference between carbon-12 and carbon-14 is the number of neutrons in each of their atoms. ... Atoms of both isotopes of carbon contain 6 protons. Atoms of carbon-12 have 6 neutrons, while atoms of carbon-14 contain 8 neutrons.
Explanation:
haha carbon atoms go brrrrr
what happen when a piece of silver metal is added to the copper sulphate solution
Answer:
Explanation:When silver Ag metal is added to copper sulphate CuSO4 solution, no reaction takes place as silver is less reactive than that of copper and cannot displace copper from its solution. Hence, when a piece of silver metal is added to copper sulphate solution there will be no reaction.
Answer:
There will be no reaction
Explanation:
Therefore, when silver Ag metal is added to copper sulphate CuSO4 solution, no reaction takes place as silver is less reactive than that of copper and cannot displace copper from its solution. Hence, when a piece of silver metal is added to copper sulphate solution there will be no reaction.
I NEED HELP, PLEASE AND THANK YOU! <3
The doctor speaks to his patients in a soothing voice, maintains eye contact, and is aware of his body language. Which best describes what these actions will do for the patients?
allow for successful communication between diverse cultures
allow for greater chance of stereotyping patients
allow for an increase in misdiagnosis
allow for greater chances for a sentinel event
Answer:allow for greater chances for a sentinel event
Explanation:
Answer:
The last one
Explanation:
To much eye contact may cause discomfort to the patient. I mean like looking at the client is good but with out a blink breaking is weird.
if a solution has a pOH of 5.2 the pH of the solution is
Answer:
ph=5.2 solution is acidic
Lysol Power Toilet Bowl Cleaner contains 9.5% hydrochloric acid. Explain why this would be necessary to clean toilet bowls that have white or rust-coloured deposits
Answer:
The acid will absolutely remove the hard water deposits that are trapping the stains. The longer it soaks, the less you have to scrub. It works for hard water stains, limescale, and rust!
Explanation:
hope this helped you out.
HELP
In the following acid-base reaction,
NH4+ is the
H2PO4- (aq) + NH3(aq) → HPO42- (aq) + NH4+(aq)
Answer:
C
Explanation:
The NH4^+ is the conjugate acid because it is formed from the base by accepting a proton.
Browstead - Lowry definitionAn acid base reaction can be defined according to;
ArrheniusBrownstead - LowryLewisThe NH4^+ is the conjugate acid because it is formed from the base by accepting a proton as can eaily be observed in the reaction equation as shown.
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The catalytic conversion of ammonia to nitric oxide is the first step in a three-step process, which ultimately results in nitric acid. Balance the equation for the reaction. NH3(g) + O2(g) → NO(g) + H2O(g)
a. 2, 1, 2, 1
b. 3, 2, 3, 3
c. 4, 3, 2, 6
d. 4, 5, 4, 6
The balance equation for the reaction is
4NH₃(g) + 5O₂(g) —> 4NO(g) + 6H₂O(g)The coefficients are 4, 5, 4, 6
Option D. 4, 5, 4, 6 gives the correct answer to the question.
From the question given above, we obtained:
NH₃ + O₂ —> NO + H₂O
The above equation can be balance as illustrated below:
NH₃ + O₂ —> NO + H₂O
There are 2 atoms of H on the right side and 3 atoms on the left side. It can be balance by writing 4 before NH₃ and 6 before H₂O as shown below:
4NH₃ + O₂ —> NO + 6H₂O
There are 4 atoms of N on the left side and 1 atom on the right side. It can be balance by writing 4 before NO as shown below:
4NH₃ + O₂ —> 4NO + 6H₂O
There are 2 atoms of O on the left side and a total of 10 atoms on the right side. It can be balance by writing 5 before O₂ as shown below:
4NH₃(g) + 5O₂(g) —> 4NO(g) + 6H₂O(g)
Now, the equation is balanced.
The coefficients are 4, 5, 4, 6
Thus, Option D. 4, 5, 4, 6 gives the correct answer to the question.
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Select some particular plant or animal and find out how it has been improved because of the study of genetics. The following examples are given, but you may select some other topic if you like. Be sure that you have the topic and the method (written or oral) of reporting approved before you do your research. If you choose an oral report, it should be at least 3 minutes in length. If you choose a written report it should be at least 500 words in length.
Do some research into thornless varieties of plants.
What plants are available which do not have thorns?
Is thornlessness a mutation?
When and where was the possibility of growing thornless varieties of plants discovered?
How do these varieties compare with the variety that has thorns?
Consult seed catalogs, gardening books, and magazines in the library.
Do some research into the new variety of pumpkins that do not have hulls on their seeds.
Is the flavor of the new variety as good as the flavor of the older varieties, or is the new variety raised only to have seeds without hulls?
How are the seeds prepared?
Is the pumpkin seed a good source of protein?
Consult seed catalogs, gardening books, and gardening magazines.
Study the potato famine in Ireland.
Study how the use of some modern types of potatoes can help to overcome such famines.
Give some examples of potatoes which are hardy against disease.
Study the careful breeding experiments that resulted in disease resistant potatoes.
What makes them hardier and more disease resistant?
What makes them hardier and more disease resistant?
Do some research to find out about the new breeds of cattle that provide much better beef than the older breeds.
Consult a genetics book from the library to determine the names of such cattle.
what makes these breeds better? Are they cared for the same way? Do they have any drawbacks in terms of cost of breeding and raising?
You may want to investigate some of the diseases which are inherited.
Consult a genetics textbook from the library.
You may also need to look up some of these in a medical textbook or the Journal of Heredity.
Who is more likely to inherit them? Why?
How do I balance
H2O ⇾ H2 + O2
How many moles of H2 are in a flask with a volume of 2500 mL at a pressure of 30.0 kPa and a temperature of 27oC?
Answer:
0.0300 moles of H₂
Explanation:
The original equation is PV = nRT. We need to change this to show moles (n).
n = [tex]\frac{PV}{RT}[/tex]
It's important to convert your values to match the constant (r) in terms of units.
30.0 kPa = 0.296 atm
2500 mL = 2.50 L
27 °C = 300 K
Now, plug those values in to solve:
n = [tex]\frac{(0.296)(2.50)}{(0.0821)(300)}[/tex] - for the sake of keeping the problem clean, I didn't include the units but you should just to make sure everything cancels out :)
Finally, you are left with n = 0.0300 moles of H₂
Which subatomic particle orbits the nucleus?
O the electron
o the neutron
O the proton
it’s electron btw
Answer: Subatomic particle which orbits the nucleus is electron.
Explanation:
Every atom contains three sub-atomic particles. These are protons, neutrons and electrons.
Protons contain a positive charge, neutrons have no charge and electrons have a negative charge.
Both protons and neutrons reside inside the nucleus of the atom whereas electrons reside outside the nucleus of atom and revolve around the nucleus.
Therefore, it is concluded that subatomic particle which orbits the nucleus is electron.
2. How many moles of hydrogen are produced from the reaction of 3.86 moles of zinc with an excess of
hydrochloric acid?
Answer:
as per given balanced equation one mole Zn produces 1mole Hydrogen
when reacted with excess acid.
So 3 moles Zn will give 3moles Hydrogen
Explanation:
According to the balanced chemical equation, one mole of Zn produces one mole of hydrogen . Therefore, 3.86 moles of Zn metal will produce 3.86 moles of hydrogen gas.
What is mole ratio ?Mole ratio refers to the ratio of the number of moles of one substance in a chemical reaction to the number of moles of another substance in the same reaction.
It is derived from the balanced chemical equation for the reaction, which indicates the relative amounts of each substance involved in the reaction.
Mole ratio is important in stoichiometry, which is the study of the quantitative relationships between reactants and products in a chemical reaction.
The given chemical reaction is written as follows:
Zn + 2 HCl ⇒ ZnCl₂ + H₂
According to the balanced chemical equation, one mole of Zn produces one mole of hydrogen . Therefore, 3.86 moles of Zn metal will produce 3.86 moles of hydrogen gas.
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Calcium carbonate + hydrochloric acid forms copper ___ + water + carbon dioxide
What does it form copper what please help me
Answer:
The answer copper carbonate
Calculate magnetic moment of a divalent ion in aqueous solution, if the electronic configuration is [Ar] 3d5 .
Answer:
5.47 B.M
Explanation:
✓We were given electronic configuration of argon as [Ar] 3d5.
✓This is a divalent ion. It has atomic number of 25.
✓magnetic moment can be calculated using below expresion
√[n(n+2)] .....................eqn(1)
✓ It has 5 unpaired electrons. Then n= 5
✓ [n(n+2)]
✓ substitute the ( n= 5) into eqn(1)
Then magnetic moment= [n(n+2)]
= [ 5(5+2) ]
= 5.47BM
In an exothermic the change in enthalpy is usually
Positive, because the potential energy of the reactants is higher than the potential energy of the products
Neutral, because the potential energy of the products and reactants cancel each other out.
Negative, because the potential energy of the reactants is higher than the potential energy of the products
Positive, because the potential energy of the reactants is lower than the potential energy of the products
Answer:
Negative, because the potential energy of the reactants is higher than the potential energy of the products
Explanation:
Exothermic reaction is a reaction in which heat is released to surrounding. This is due to the fact that the heat content of the reactant is higher than the heat content of product thus producing a negative enthalpy change (ΔH) i.e
Enthalpy change = Heat of product – Heat of reactant
ΔH = Hp – Hr = negative
Considering the options given in the question above, the correct answer is:
Negative, because the potential energy of the reactants is higher than the potential energy of the products