Answer:
Molecules of compounds have atoms of two or more different elements. For example, water (H2O) has three atoms, two hydrogen (H) atoms and one oxygen (O) atom.
Explanation:
Two skaters stand on ice. one weights 250 N, and the other weights 500 N. They push against each other and move in opposite directions. Describe the momentum of each skater after they push away from each other.
Answer:
Because law of momentum, makes it equal
Suppose there was a release of 1 mole of Alpha emission particle and 1 mole of Beta emission particles and both particles are accelerated to 20.50 MeV. What is the total energy in kJ/nuclei? Hint: 1 MeV = 1 x 106 eV and 1 eV = 1.602 X 10-19 J and 1 kJ = 1000 J, and finally in 1 mole there are Avogadro's number of particles which is 6.02214 x 1023 particles/mole. Report your answer in scientific notation to 2 decimal places for example 1.23 x 10-4 would be entered as 1.23 E-4.
238 92 U → 4 2 He + 234 90 Th and then 234 90 Th → 0
-1e + 234 91 Pa
Explanation:
translate the following word equation in the form of balance come alive with your number is aluminium + hydrochloric acid and Aluminium chloride + nitrogen
where do we get the mass number
Explanation:
Mass number is the sum of the numbers of protons and neutrons present in the nucleus of an atom.
Round each number to four significant figures
a. 84,791
b. 256.75
C. 431,801
d. 0.00078100
Answer:
a.
84,791 » 8479
b.
256.75 » 256.8
c.
431,801 » 4318
d.
0.00078100 » 0.0007810
Explanation:
[tex].[/tex]
A photon of 498mm was emitted from a silicon atom. calculate the energy of all the atomic levels of silicon and show that the atomic levels are quantized.
A photon is an elementary particle that has zero invariant mass and travels in a vacuum with a constant velocity. It is capable of generating electromagnetic phenomena since it carries all forms of electromagnetic radiation:
X-rays Ultraviolet light Visible light Gamma rays Infrared light Radio waves Microwaves and radio wavesThe photon presents wave and corpuscular properties, this means that it behaves as a wave in certain phenomena, such as refraction in a lens; and as a particle when it interacts with matter to transfer energy. The latter is expressed as follows:
[tex]E=\frac{hc}{lambda} = hv[/tex]
E is the energy, in physics it is defined as the capacity to do work.h is Planck's constant, a physical constant that plays a role in the theory of quantum mechanics and it is a constant between the energy of a photon and the frequency of its electromagnetic wave ([tex]E = hv[/tex]) Its value is 6.63 x 10^-34 J/s.c is the speed of light, which is 3x10^8 m/s.lambda (λ) is the wavelength, the distance traveled by a periodic disturbance propagating in one cycle. v is the frequency of the wave, it is the inverse of the wavelength, the number of repetitions per unit time of any periodic event.This means that each photon has energy that is proportional to the frequency of light. In this case, the energy is quantized, which means that the energy of the photons is restricted to certain values. The energy at subatomic levels occurs in packets that refer to the photon, which are the packages of energy and each one correspond to different types of radiation.
This differs from classical waves, which can gain or lose arbitrary amounts of energy.
If we apply the equation and replace the information, we have:
[tex]E=\frac{6.63 x 10^{-34} J/s x 3 x 10^{8} m/s }{498 nm} = 3.99 x 10^{-28} J[/tex]
So 3.99 x 10^-28 J is the amount of energy of the photon of 498 nm emmited from a silicon atom.
Now we will show that the atomic levels are quantized. An atom has ground state (n=1) energy of 13.6 eV. Higher states means the atom is at an excited state. When this happens, an electron from an atom loses energy and makes a transition to a lower state. To avoid this and conserve energy, the atom emits a photon with an amount of energy that equals the difference of energy between a ground state and another state. So we can calculate the energy of the electron in different states.
[tex]E_{n} = \frac{-13.6 ev}{n^{2} }[/tex]
[tex]E_{1} = \frac{-13.6 ev}{1^{2} }=-13.6 ev[/tex]
[tex]E_{2} = \frac{-13.6 ev}{2^{2} }=-3.4 ev[/tex]
[tex]E_{3} = \frac{-13.6 ev}{3^{2} }=-1.511 ev[/tex]
N represents the principal quantum number, which is the overall energy of each orbital. This energy increases as its distance from the nucleus increases. Here we can se that the value of energy of n=1 is higher than energy of n=2, and this one is higher from the energy of n=3. This means each level has a specific energy and it is quantized according to the value of n.
So, a photon is an elementary particle which carries radiation and presents a wave-corpuscle duality, where particles may exhibit wave-like behavior in some experiments while appearing as particles in others. A photon is emmited when an atom loses energy, to conserve this energy and avoid a transition to a lower state. The electron energy is quantized because it is restricted to characteristic values, only taking non-continuous values. In this question, the amount of energy of the photon emmited is 3.99 x 10^-28 J. And the atomic levels are quantized according to the principal quantum number.
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A procedure calls for 4 parts reagent A to 16 parts water.What is the dilution of reagent A in water?
a) 4/16
b) 1/5
c) 1/4
d) 4/12
my guess answer iss 1/4 if incorrect sorr
1/5 is the dilution of reagent A in water.
Explanation:
The dilution factor of the diluted solution is determined by dividing the final volume of the diluted solution by the volume of the undiluted solution.[tex]D.F.=\frac{V_f}{V_i}[/tex]
Where:
D.F = Dilution factor
[tex]V_f[/tex] = Final volume of the diluted solution
[tex]V_i[/tex]= Initial volume of the undiluted solution
And the dilution is represented as 1 : D.F.Given:
4 parts of the reagent and 16 parts of water are mixed together to form a diluted solution.
To find:
The dilution of reagent A in water
Solution:
Parts of reagent A =[tex]V_i = 4[/tex]
Parts of water = 16
Final volume of solution = [tex]V _f = 4 + 16 = 20[/tex]
The dilution factor of reagent A:
[tex]D.F=\frac{20}{4}=5[/tex]
The dilution of the reagent A = [tex]1:5=\frac{1}{5}[/tex]
1/5 is the dilution of reagent A in water
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Give reason
1) The efficiency of a practical machine is less that 100%.
1) The efficiency of a machine can be increased by using lubricants in the movable parts.
Explanation:
The efficiency of a practicle machine is less than 100% because some of the applied force is wasted due to oovercoming friction.The efficiency of a machine can be increased by using lubricants in the movable parts because lubricants helps to reduce friction.I hope it helped U
stay safe stay happy
What do we call planets that are not in our solar system
I need help with this question
Answer:
ok ok ok okbokvjhkeokkd
A 1-L soda bottle contains dissolved carbon dioxide gas. Which bottle would have the highest concentration of dissolved gas?
a bottle that is sealed
a bottle that was opened 1 minute ago
a bottle that was opened 1 hour ago
a bottle that was opened 1 day ago
Mark this and return
Answer:
A bottle that is sealed would have the highest concentration.
Explanation:
When you put a gas into a container, the concentration or the amount of mol inside the bottle would be highly concentrated. If you open the bottle, the CO2 would spread outwards and leave the bottle giving more room between each molecule. The longer you open the bottle, the less concentrated the gas will be.
HELP IM TIMED!!!!!!!!!
Yellowstone National Park has an average of about 4500 bison living in it. The park covers 3472 square miles. What is the population density of bison living in Yellowstone? a. 1.3 bison/mi^2 b. 16 bison/mi^2 c. 77 bison/mi^2 d. 0.77 bison/mi^2
Answer:
A. 1.3 bison/mi^2
Explanation:
4500 bison divided by 3472 sq miles is 1.3 bison per mile squared.
where did they start water conservation in tamil nadu . short answer
Explanation:
The 2019 water crisis in Chennai has made us realize the importance of saving water more than ever. Water, as we all know, is a finite resource without which our planet would be a barren wasteland. Today with our increasing population it would be logical to say that our water consumption has also increased. And with increasing demand and lesser supply, water scarcity arises. Our ancestors who had foreseen the potential dangers of water scarcity had developed methods to conserve water that was suited for the varied terrain of the Tamil-speaking kingdoms.
Traditional Rainwater Conservation methods of Tamil Nadu
Eri
There are no perennial rivers in Tamil Nadu except the Thamirabharani River which flows through Thirunelveli district. And so, several hundred years ago a simple system was devised to utilize the rainwater to the fullest. An Eri or tank system is one of the oldest forms of water conservation systems in India. Many Eris are still in use in Tamil Nadu and play an active role in irrigation. They act as water reservoirs and flood control systems. They prevent soil erosion, recharge groundwater, and prevent wastage of runoff water during heavy rainfall.
Kudimaramathu
Kudimaramathu is one of the old traditional practice of stakeholders participating in the maintenance and management of irrigation systems. During earlier days, citizens of a village used to actively participate in maintaining the water bodies of their village by deepening and widening the lakes and ponds and restoring the water bodies back to their original form. The silt, rich in nutrients, collected in the process would be used by the farmers themselves in their field. A sense of collective ownership ensured the continued survival of the water bodies.
How does an atom change if all of its electrons are removed?
How does an atom change if all of its electrons are removed?
The atom’s volume increases.
The atom’s mass increases.
The atom becomes positively charged.
The atom becomes negatively charged.
Answer:
c
Explanation:
it becomes positively charged
Answer:
The atom becomes positively charged.
Explanation:
If ALL OF THE ELECTRONS are removed, then there are, no matter what, less electrons than protons in an atom. And, since the atom has less electrons than protons, it becomes positively charged.
When Hydrogen and Oxygen
form a molecule, what happens to their neutrons?
A. They share their neutrons:
B. They both lose neutrons.
C. Nothing happens to their neutrons.
I need help ASAP!!!!
The table shows the charge on three unknown subatomic particles,
Charged Particles
Particle Charge on Particle
A
Positive
B
B
No charge
С
Negative
Which particle is most likely present in the nucleus of the atom?
O Only particle A
O Only particle C
O Both particles A and B
Both particles B and C
Answer:
Both particles A and B
Explanation:
A nucleus contains both protons and neutrons .
But protons are positively charged whereas neutrons have no charge.
[tex].[/tex]
Both particles A and B are most likely present inside the nucleus of the atom. Therefore, option (c) is correct.
What is the nucleus of an atom?The nucleus of an atom contains the particles protons and neutrons. Both the solid particles in an atom are responsible for 99.9% of the mass in the nucleus.
The protons are the positively charged particles that lie inside the nucleus. Therefore, the nucleus of an atom has a positive charge on it while the negatively charged electrons rotate around the nucleus.
The neutrons do not carry any charge. So we can say that the neutrons are neutral. Therefore, the charge on the nucleus is only due to protons.
The atomic powers which are holding the protons and the neutrons inside the nucleus are also vast. The protons are prsent very close to each other inside the tiny nucleus, so the electrostatic forces of repulsion act in the nucleus.
Therefore, particles with no charge and positive charge are most present in the nucleus of the atom.
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You want to test the effect of soil acidity on plant growth. Which of the
following is an example of a controlled experiment to test this?
A. The plant type, amount of light, and amount of water are kept
constant while soil acidity is varied for plants in a greenhouse.
B. The soil acidity of plants in a garden that get light and water from
their surroundings is increased after the plants grow to a height of
100 cm.
C. The plant type, soil acidity, amount of light, and amount of water
are all varied and studied in a laboratory.
D. Soil acidity and height of plants growing in a 10 m2 yard are
measured twice in July and twice in August.
Answer:
I believe the answer to your question would be A. this is because it is controlled with a good habitat and also has good variants that are needed in a good plants growth.
Explanation:
Assertion : When the added electron goes to smaller n=3 quantum level, the electron-
electron repulsion is much less.
Reason: The added electron occupies a smaller region of space .
It is due to low volume of electron that causes large distance between two electrons.
When the added electron goes to smaller quantum level, the repulsive force between two electrons is less because the electron which is added occupies small space due to less volume so there is a large distance between two electrons that leads to less force of repulsion.
If the electron has more volume so it occupies more space and there will more repulsive force between two electrons so that's why we can say that the smaller volume of electron is the reason of less repulsive force.
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what is an homeostasis?
Answer:
it's a property of a cell, tissue and organisms that allows to maintain and regulate the stability and constancy to function properly
Give reasons. 1. There is interrelation between wildlife and vegetation 2. Various activities of the man have helped for the survival of the wildlife. 3. Establishment of national parks and wildlife conservation area help for the protection of wildlife. 4. Different animals are put under Red List. 5. Giant hornbill is critically endangered species in Nepal. Answer the following questions.
Answer:
Yes
Explanation:
How many nickels are there in $5.25?
Answer:
105
Explanation:
1 nickel = 5 cents
5.25 dollars x 100 cents
= 525 cents
525 cents / 5 cents
= 105 nickels
A statement that describes what scientists expect to happen every time under a given set of conditions is call a scientific
Answer:
law
Explanation:
it is called a scientific law
Define uniform and non-uniform motion.
Answer:
When a body covers equal distances in a straight line, equal intervals of time are called uniform motion
When a body covers unequal distance in equal intervals of time in a straight line is called non-uniform
Answer:
Uniform motion- is motion in which the
velocity does not change.
Non-uniform motion-occurs when the velocity of an object is not
constant : the object speeds up or slows down during its motion, or changes direction.
Hope it will help you !!
white vitriol molecular formula
and green vitriol molecular formula??
Answer:
Green vitriol- FeSO4·7H2O
white vitriol- ZnSO₄
A sunscreen preparation contains 2.70 % by mass benzyl salicylate. If a tube contains 6.0 oz of sunscreen, how many kilograms of benzyl salicylate are needed to manufacture 340 tubes of sunscreen?
We know that the sunscreen preparation contains a 2.7% by mass of Benzyl Salicylate. From this, we will find that they need 1.559 kg of Benzyl Salicylate to make 340 tubes of sunscreen.
The initial data means that if the total mass of sunscreen is M, then the mass of Benzyl Salicylate will be 2.7% of M, or:
(2.7%/100%)*M = 0.027*M
Now, we know that a tube contains 6.0 oz of sunscreen.
Then M = 6.0oz
A tube contains:
0.027*6.0oz = 0.162 oz.
Then in 340 tubes, we will need 340 times 0.162 oz of Benzyl Salicylate, this is:
340* 0.162 oz = 55.08oz
And we want this quantity in kg.
Knowing that:
1oz = 0.028kg
Then 55.08oz is 55.08 times 0.028kg:
55.08*0.028kg = 1.559 kg
So they will need 1.559 kg of Benzyl Salicylate to make 340 tubes of sunscreen.
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4.4 x 10^-9
What’s this in standard form or scientific notation
Answer:
How to Convert a Number to Standard Form
Move the decimal point in your number until there is only one non-zero digit to the left of the decimal point. ...
Count how many places you moved the decimal point. ...
Write your scientific notation number as a x 10b and read it as "a times 10 to the power of b."
Explanation:
Los elementos que forman aniones con carga -1 y una capa externa estable de ocho electrones pertenecen al grupo de los:
Los elementos que forman aniones con carga -1 y una capa externa estable de ocho electrones pertenecen al grupo de los: halógenos.
Para alcanzar la estabilidad, los átomos siguen la regla del octeto: ganan, pierden o comparten electrones para tener 8 electrones en su capa externa (capa de valencia).
Los elementos del Grupo 17 de la Tabla Periódica, conocidos como halógenos, tienen 7 electrones en su capa de valencia. Así, tienden a ganar 1 electrón para completar su octeto. Como los electrones tienen carga negativa, al ganar 1 electrón los aniones quedan con una carga de -1.
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What was alchemy?
A. A part of chemistry that experimented only with metals
B. An area of research that investigated all areas of science using
chemistry
C. An early form of chemistry based on experiments and evidence to
test ideas
D. An attempt to turn cheap metals into gold and develop potions using superstitious practices
Answer:
D
Explanation:
its a very old study and philosophy of how to change basic substances such as metals into other substances
The metal zirconium becomes superconducting at temperatures below 3.4000K.
Calculate the temperature at which zirconium becomes superconducting in degrees Celsius. Be sure your answer has the correct number of significant digits.
Answer:
-269.75 degrees Celsius
Explanation:
If I have 4.9 moles of gas at a pressure of 2.0 atm and a temperature of 56 Celsius, what is the volume of the cantainer that the gas is
in? (R=0.0821 L*atm/mol*K)
Answer: 132 liters. or 130 liters with 2 sig figs.
Explanation: Use the ideal gas law: PV = nRT
We want V, so rewrite and plug in data:
Temperture must be in Kelvin (add 273.15 to
V = (nRT)/P
V = (4.9 moles)*(0.0821 L*atm/molK)*(328.2K)/(1atm)
V = 132 liters (3 sig figs). 130 liters with 2 sig figs
