Answer:
[tex]3.7837 \times {10}^{ - 19} j[/tex]
Explanation:
[tex]e = \frac{hc}{ \lambda} \\ where \: h \: = plancks \: constant \\ and \: c = speed \: of \: light[/tex]
Planck constant value: h = [tex]6.62606957 \times {10}^{ - 34} j \: s\: [/tex]
speed of light constant: c = [tex]299,792,458 \frac{m}{ s} [/tex]
[tex]hc = 6.62606957 \times {10}^{ - 34} j \: s\: \: \times \\ 299792458 = 1.98645 \times {10}^{ - 25} j \: m[/tex]
Divide the wavelength in nanometers by 10^9 to calculate the value in meters.
[tex] \frac{525}{ {10}^{9} } = 5.25 \times {10}^{ - 7} m[/tex]
[tex]e = \frac{hc}{ \lambda} \\ = \frac{1.98645 \times {10}^{ - 25} j \: m}{ 5.25 \times {10}^{ - 7} m} [/tex]
[tex] = 3.7837 \times {10}^{ - 19} j[/tex]
Magnesium has three isotopes: Magnesium-24 with a mass of 23.98504 amu and an abundance of 78.70%, magnesium-25 with a mass of 24.98584 amu and an abundance of 10.13%, and magnesium-26 with a mass of 25.98259 amu and an abundance of 11.17%.
Without doing the calculations, should the atomic mass of magnesium be closer to 25, 26, or 27 amu? Explain how you know.
What element has the electron configuration 1s22s22p63523p64523d4?
A.Chromium (Cr)
B.Magnesium (Mg)
C.Manganese (Mn)
D.Iron (Fe)
Explanation:
It's none of these.
Cr- 1s2 2s2 2p6 3s2 3p6 4s1 3d5
Mg- 1s2 2s2 2p6 3s2
Mn - 1s2 2s2 2p6 3s2 3p6 4s2 3d5
Fe- 1s2 2s2 2p6 3s2 3p6 4s2 3d6
I think there's a mistake in the question.
a solution was made by dissolving a salt in water. what is the correct term for the salt when dissolved in water.
a precipitate
b insoluble
c solute
d solvent
Solute
The salt being dissolved is the solute.
how many calories are required to boil 75 grams of water not in sig figs
Well, each ml of water requires one calorie to go up 1 degree Celsius, so this liter of water takes 1000 calories to go up 1 degree Celsius. (There are 1000 ml, each of which needs to have its temperature raised.)
How much heat is needed to vaporize 10.0 grams of water?
Your grandmother wants to build a small garden in her backyard.She lives near a city and doesn't have a large budget for this.Should she use an organic or inorganic fertilizer?
Answer:
So if you are buying, Inorganic is cheaper but at the cost of it's quality, organic fertilizer is better quality that's why it is more expensive, both work so if you want the cheaper option that's fine it still works
Explanation:
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A scientist is measuring the pressure that is exerted by each of the following gases in the atmosphere: carbon dioxide,
oxygen, and nitrogen. Which term most likely describes what she is measuring?
O final pressure
atmospheric pressure
O combined pressure
O partial pressure
Answer:
I'm assuming atmospheric pressure, since it says she is measuring pressure exerted my atmospheric gases
The heat of solution of KI is 20.3 kJ/mol.
This means that when one mole of KI dissolves in water the process will be
PLEASE EXPLAIN ANSWER
a. Exothermic, ΔH is positive
b. Exothermic, ΔH is negative
c. Endothermic, ΔH is negative
d. Endothermic, ΔH is positive
Since the heat of solution of KI is 20.3 kJ/mol, the answer to the question is a. Exothermic, ΔH is positive
There are two types of chemical reactions namely exothermic and endothermic reaction.
For exothermic reactions, heat is released. So, ΔH is positiveFor endothermic reactions, heat is absorbed. So, ΔH is negativeGiven the heat of solution of KI as 20.3 kJ/mol.
Since it is positive, the reaction is exothermic and ΔH is positive
Since the heat of solution of KI is 20.3 kJ/mol, the answer to the question is a. Exothermic, ΔH is positive
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a) Two ways to create a positive ion:
Positive ions are formed by atoms or molecules suffering an inelastic collision with an energetic electron in which an electron is lost from the atom or molecule (electron impact ionization). The degree of ionization of the plasma depends strongly on the electron density and energy distribution in the gas.
Which is the term for a pattern that repeats? A)metal B)metalloid C)noble gas
D)non metal/
if the reactants of a reaction have ab initial mass of 25 grams what is the mass of the product?
Answer:
It remains the same
Explanation:
The law of conservation of mass states that in a chemical reaction, the total mass of reactants is equal to the total mass of products. For example, the mass of sodium plus the mass of chlorine that reacts with the sodium equals the mass of the product sodium chloride.
What is the shortest day of the year known as? A.vernal B.equinox C.winter D.solstice summer solstice E.autumnal equinox
Answer:
summer solstice
Explanation:
on june solstice the northen hemisphere leans more toward the sun giving us longer days and more strong sunlight and It's the opposite in the Southern Hemisphere where june marks the start of winter thus its the shortest day of the year
Taku mixed some water and juice crystals to make a fruit drink.
(a) The solute is
(b) The solvent is
According to the concept of solubility, thing which dissolves is solute and in which it is dissolved is solvent , hence juice crystals are solute and water is solvent.
What is solubility?Solubility is defined as the ability of a substance which is basically solute to form a solution with another substance. There is an extent to which a substance is soluble in a particular solvent. This is generally measured as the concentration of a solute present in a saturated solution.
The solubility mainly depends on the composition of solute and solvent ,its pH and presence of other dissolved substance. It is also dependent on temperature and pressure which is maintained.Concept of solubility is not valid for chemical reactions which are irreversible. The dependency of solubility on various factors is due to interactions between the particles, molecule or ions.
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The half life of iodine-131 is 8.040 days. What percentage of an iodine-131 sample will remain after 40.20 days?
The percentage of an iodine-131 sample that will remain after 40.20 days is 3.125%
We'll begin by calculating the number of half-lives that has elapsed. This can be obtained as follow:Half-life (t½) = 8.040 days.
Time (t) = 40.20 days
Number of half-lives (n) =?[tex]n = \frac{t}{t_{1/2}} \\\\n = \frac{40.20}{8.040}\\\\[/tex]
n = 5Thus, 5 half-lives has elapsed.
Finally, we shall determine the percentage of an iodine-131 sample that remains. This can be obtained as follow:Number of half-lives (n) = 5
Percentage remaining =?[tex]N = \frac{1}{2^{n} } * N_{0} \\\\N = \frac{1}{2^{5} } * N_{0} \\\\N = \frac{1}{32} * N_{0}\\\\[/tex]
Divide both side by N₀
[tex]\frac{N}{N_{0}} = \frac{1}{32} \\\\\frac{N}{N_{0}} = 0.03125\\\\[/tex]
Multiply by 100 to express in percent
[tex]\frac{N}{N_{0}} =[/tex] 0.0312 × 100
= 3.125%Therefore, the percentage of an iodine-131 sample that remains is 3.125%
NOTE:[tex]\frac{N}{N_{0}}[/tex] => Fraction remaining
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WILL MARK AS BRAINLIEST IF CORRECT
Answer:
I don't know what is the actual answer
Can stars less massive than our sun produce elements up to iron?
Answer:After the hydrogen in the star's core is exhausted, the star can fuse helium to form progressively heavier elements, carbon and oxygen and so on, until iron and nickel are formed. ... Supernova explosions result when the cores of massive stars have exhausted their fuel supplies and burned everything into iron and nickel.
An atom of beryllium can be represented as 9/4Be.
Describe the structure of the beryllium atom.
in your answer make reference to the number of subatomic
particles and where they are found in the atom
Plz answer these
Ill mark you brainliest
Answer:
I don't do chemistry
Explanation:
sorry
Hello! please help :(
Which statements about nuclear fission and nuclear fusion are true? Select the two correct answers. (1 point)
They both occur in the nucleus of an atom
They both involve two atoms fusing into one atom
They both reloase large amounts of energy
They both involve one atom splitting into two atorns
Statements that describes nuclear fission and nuclear fusion as regards this question are:
C: They both release large amounts of energy
D:They both involve one atom splitting into two atoms.
Both fission and fusion can be regarded as nuclear reactions that brings about production of energy. However they have different applications.Fission can be explained as the splitting of a heavy as well as unstable nucleus into two nuclei , but this nuclei are lighter compare to the mother nucleus.
Fusion on the other hand can be regarded as a process involving two light nuclei coming together to form one and then release vast amounts of energyFor instance, uranium will undergo fission to produce strontium and krypton nuclei
Therefore, option C, D are right.
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Answer:
C: They both release large amounts of energy
D: They both involve one atom splitting into two atoms
both magnesium rod and aluminium rod can be used as conductor of electricity. Why?
Answer:
Both Magnesium and aluminium rods are metals, hence they allow flow of charged electrons due to high drift velocity.
Explanation:
• An electric conductor is material which allows flow of electric current.
[tex].[/tex]
The Magnesium (Z = 12) is an alkaline earth metal and the Aluminium (Z = 13) is a metal in the Boron Group. One characteristic of the metals is that they have facility to lose electrons, wich means facility to conduct electricity.
Moreover, the metals are ductile, so it is easy to turn them into wires. For example, the light poles has wires made by copper because the copper is another metal, so its have the same properties as indicated above.
I hope I've helped. =D
Enjoy your studies! \o/
QUICK QUESTION: On the Bohr model, how come potassium has 19 electrons in its valence shell if potassium has a K+? Isn’t it suppose to have 18 electrons? I thought that if an ion has a positive charge, the atom has lost electrons. Pls help me
I WILL GIVE BRAINLIEST TO THE BEST ANSWER
Answer: K only has 1 valence electron. It will leave with only a little effort, leaving behind a positively charged K^+1 atom.
Explanation: A neutral potassium atom has 19 total electrons. But only 1 of them is in potassium's valence shell. Valence shell means the outermost s and p orbitals. Potasium's electron configuration is 1s^2 2s^2 2p^6 3s^2 3p^6 4s^1. The 4s orbital is the only orbital in the 4th energy level. So it has a valency of 1. This means this electron will be the most likely to leave, since it is the lone electron in the oyutermost energy level (4). When that electron leaves, the charge on the atom go up by 1. The atom now has a full valence shell of 3s^2 3p^6, the same as argon, Ar.
I need help with these questions.
Answer:
descritive advective also know as qualitative
12. Using the two equations E = hv and c= lv, derive an
equation expressing E in terms of h, c, and \.
[tex]\\ \sf\longmapsto c=\lambda v[/tex]
[tex]\\ \sf\longmapsto v=\dfrac{c}{\lambda}[/tex]
Now
[tex]\\ \sf\longmapsto E=hv[/tex]
Put value of v found before
[tex]\\ \sf\longmapsto E=\dfrac{hc}{\lambda}[/tex]
Knowing how electrons behave in metallic materials, describe why metals make great conductors of heat
Answer:
Below
Explanation:
Metallic compounds are excellent conductors of heat due to the fact that their electrons, instead of orbiting their respective atoms, form a sea of electrons around the positively charged nuclei of the interacting metal ions. These electrons are able to move freely around and bond, allowing them to conduct heat well.
Hope this helps! :)
what can you do to see what season another planet experiences?
Answer:
Observe the other planet throughout the year. Look at the environment when the season changes to see what changes in the environment.
Answer:
Every planet in the solar system has seasons. Extraterrestrial seasons are hardly noticeable on some planets (Venus), mindbogglingly extreme on others (Uranus) and in some cases simply impossible to define (Mercury).
describe the composition and structure of the compound fluoride
Answer: sodium (Na +) cation and fluoride (F -) anion
Explanation:
Formula and structure: The chemical formula of sodium fluoride is NaF and its molar mass is 41.99 g/mol. It is a simple ionic compound, made of the sodium (Na +) cation and fluoride (F -) anion. The solid salt exists as cubic crystals similar to the crystal structure of sodium chloride (NaCl).
Qué tipo de energía tiene un sacapuntas
Answer:
creo q es electrico
Explanation:
What are the 4 properties of hydrogen bonds?
Answer:
Solubility, Volatility, Viscosity and Surface Tension.
Hydrochloric acid reacts with sodium hydroxide according to the equation:
NaOH + HCl 2 NaCl + H2O
25 cm of NaOH was neutralized by 26 25 cm of 0 1 mol/dm HCI
a
Calculate how many moles of HCI was neutralized
b
Calculate how many moles of NaOH was neutralized.
Calculate the concentration of the NaOH used
Answer:
Explanation:
Hydrochloric acid reacts with sodium hydroxide according to the equation:
NaOH + HCl ------> NaCl + H2O
25 cm of NaOH was neutralized by 26. 25 cm^3 of a 0.1 M solution of HCl.
Calculate how many moles of HCI was neutralized
if 1 liter of the HCl has 0.1 moles, 100 ml has 0.01 moles
so 26.25 ml has 0.01 X26.25/100 moles or 0.002625 moles
b
Calculate how many moles of NaOH was neutralized. the reaction is 1:1
so 0.002625 moles of NaOH were reacted.
Calculate the concentration of the NaOH used
25 ml of NaOH were used so the concentration was
(0.002625/25) x 10^3=0.000101X1000 =0.105 MOLES/LITER