Answer:
Relative dating is based on the positions of fossils in rock layers. Lower layers were laid down earlier, so they are assumed to contain older fossils. This gives the fossil an approximate age in years. Absolute dating is often based on the amount of carbon-14 or other radioactive element that remains in a fossil up until extinction.
Relative dating is a method of dating where the geologic events are arranged and the rocks are left behind in a sequence. They function on the basis of the stratigraphy and don't provide us with actual numeric data.
It provides us with the relative ages such as mass extinction the fossils are superimposed. It is based on the position of fossils in the layers of the rocks.Learn more about the discoveries to explain how the fossil record.
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as the amount of water decreases in a glass of water you are drinking the desitny of water also decreases true or false
Answer:
False: the density does not change. if the water became more dense, it would move onto the next state of matter, which is ice. the only thing that changes by adding more water is weight
Answer:
False
Explanation:
This is because as the volume decreases the density increases
Why is it impossible for an element to have an atomic number of 110.5? (1 point)
A_ Exactly half of the isotopes would need an atomic number of 110, and half would need an atomic number of 111, which is very unlikely.
B_ Atoms of an element all have the same whole number of protons and neutrons.
C_ Atoms with atomic numbers greater than 100 are unstable.
D_ Atoms of an element all have the same whole number of protons.
Answer:
C
Explanation:
I asked my teacher
The number of protons in an atom are always whole numbers hence it is impossible for an element to have an atomic number of 110.5. The correct answer is option D: Atoms of an element all have the same whole number of protons.
We define the atomic number as the number of protons in an atom. The number of protons in all the atoms of en element must be a whole number.
There is no half proton in the atom hence we can not have an atomic number of 110.5.
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Define measurement. why is it important in our life?
Answer:
Measurements are so often taken for granted we sometimes do not appreciate the grand importance measurements play in our lives. On a baseline level, measurements fall into the categories of weight, area, volume, length and even temperature. While we look at these various categories as stoic forms of mathematical measurements a closer examination of things we do in everyday life reveals their clear importance.
Explanation:
Measurements provide structure and remove the chaos that would result without any congruent method of understanding weight, mass, temperature, etc.
Answer:
The comparison of unknown physical quantity with the known standard quantity of the same kind is called measurement.
Measurements play an important role in daily life because they are useful to do basic tasks, such as take a child's temperature with a thermometer, make time estimations, measure out medicine and find weights, areas and volumes of different materials or substances.
Hope it helps you.Frost disappears from the window in the morning
a
Chemical Change
b
Physical Change
Answer:
the answer is b
Explanation:
Physical changes affect a substance's physical properties but do not alter its chemical structure. Types of physical changes include boiling, clouding, dissolution, freezing, freeze-drying, frost, liquefaction, melting, smoke and vaporization.
underline and identify the parts of the text on this page that use examples of how the flow of the matter through a system is driven by energy and can do the work.
The parts of the text on the page that use examples of how the flow of matter through a system is energy driven and has the capacity to do work are;
1) The flow of water down rivers passing through hydro power dams to perform the following works;
River bank particle erosionElectric power generation2) The flow of electrons that corresponds to the flow of electricity (in the reverse direction) to perform the following works;
Light bulbs turn onTelevisions are powered3) The lifting of the hammer by the cam which gains gravitational potential energy that is converted to kinetic energy as the hammer drops
The hammer is repeatedly lifted and dropped by the cam to do the following work
Hammering a metal piece into shape4) The chemical potential energy stored in bonds by virtue of the relative atomic distances which produces kinetic energy from the chemical potential energy
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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 !!
name four states of matter
Answer:
1. solid
2. liquid
3. gas
4. plasma
Explanation:
In physics, a state of matter is one of the distinct forms in which matter can exist. Four states of matter are observable in everyday life: solid, liquid, gas, and plasma.
What is the function of phloem tissue in the plant transport system?
A.it prepares food
B.it transports food
C.it transports water
D.it provides support
Answer:
option B is the right answer it helps in transfer of food.
which of the folowing idead about thr atom changed when new evidence was discoverd
Answer:
Further scientific studies showed that an atom can further be divided into subatomic particles electrons, neutrons, and protons. Thus the idea of the indivisibility of an atom changed when new evidence was discovered.
5 Why is it useful to organize the data on a graph? Explain your answer.
Answer:
Hey mate.....
Explanation:
This is ur answer....
Charts, tables, and graphs help communicators organize that data in a way that helps their audiences understand the story the data tells and, hopefully, interpret it correctly.
Hope it helps!
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In the circular flow diagram, what do firms provide to product markets?(1 point)
Answer:
Firms produce goods and services,which they sell to households in return for revenue.
Answer: Goods and Services
Explanation:
What does it mean to be in the path of totality?(1 point)
You are on part of Earth that can see a total lunar eclipse.
You are on part of Earth that can see a partial lunar eclipse.
You are on part of Earth that is in the umbra of the moon’s shadow.
You are on part of Earth that is in the penumbra of the moon’s shadow.
To be in the path of totality means that
You are on part of Earth that is in the umbra of the moon’s shadow.The path of totality is the track the Moon's umbral shadow leaves across the surface of the Earth. Its width measures up to 200 miles and its length measures up to 10,000 miles.
When the moon covers the earth's surface, a total solar eclipse has occurred.
An individual who is on the path of totality can observe the occurrence of a total solar eclipse within a short while.
Summarily, a person who is on the path of totality can see a total lunar eclipse.
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Why does America use miles but everyone else kilometers?
Answer:
So why hasn't it changed? The biggest reasons the U.S. hasn't adopted the metric system are simply time and money. When the Industrial Revolution began in the country, expensive manufacturing plants became a main source of American jobs and consumer products.
state two application of chemistry on each of the following:-
1.forensic
2.agriculture
3.industrial
4.millitary
5.space science
Help anyone can help me do this question,I will mark brainlest.
Explanation:
NA2SO3
Combination of these three elements forms following compounds.
And the compound that's going to be formed,depends on the ratio of available oxygen and sulphur.
Depends on the ratio of sulfur to oxygen...
sodium sulfate, Na2SO4
sodium sulfite, Na2SO3
sodium thiosulfate, Na2S2O3
ionic bond is present in between SO3 -2 and Na+2
structure of SO3 -2 [take - sign as delta - which here indicates,partial formal charge of oxygen] (image below)
Here,The oxygen is more electronegative.So,2 oxygen atoms drag one Electron from sulphur atom,leaving behind the formal charge of -1 on two oxygen atoms.
The third oxygen forms covalent bond by sharing 2 electrons. (Actually this ion has resonance structure)
This sulphite ion combines with two sodium ions to form two ionic bonds.This happens when sodium, being an alkali metal dontes it's valence electron to oxygen.
SO2
In Sulphur dioxide, Sulphur is bonded to 2 oxygen atoms. Oxygen is more electronegative than Sulphur and thus, shows a fixed valency of 2. As a result each oxygen forms two bonds with the Sulphur atom making its valency 4.
NAHSO4
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Questions & Answers
CBSE
Chemistry
Grade 11
Oxidation State or Oxidation Number
Question
Answers
Related Questions
The oxidation state of sulphur in NaHSO4 ?
A) 0
B) + 2
C) −2
D) + 4
E) + 6
Answer
VerifiedVerified
72.9K+ Views
Hint: The oxidation state is defined as the charge on the atom. The sum of the oxidation state of an atom in a molecule is equal to the charge on the molecule. The neutral molecules charge less species. It has zero charges.
Complete Solution :
- The oxidation number of an atom is defined as the charge on an atom that appears on the atom on forming an ionic bond. An atom which has higher electronegativity has a negative oxidation state and more electropositive elements have positive oxidation state.
- We are interested in determining the oxidation state of an atom in a molecule. We know that the net charge on a neutral atom or molecule is always equal to zero. Let’s determine the oxidation state of S in the NaHSO4 .
- The oxidation number of alkali metal that is a sodium atom is equal to +1 . Similarly the hydrogen has an +1 oxidation state. Oxygen is an electronegative element. It has an −2 oxidation state. The oxidation states are as listed below:
Element Oxidation state
Na +1
H +1
O −2
We know that the sum of the oxidation state of an atom in a neutral molecule is equal to zero. Then we have,
0 = O.S. of Na + O.S. of H + O.S. of S + 4(O.S. of O)
Let’s substitute the values of oxidation state .we have,
0 = 1 + 1 + O.S. of S + 4(−2)⇒O.S. of S= 8−2 = +6
Therefore the oxidation state of sulphur in NaHSO4 is equal to +6 . So, the correct answer is “Option E”.
H2S
Valency of sulphur is 2 in H2S
2.
What is the density of a 625 g cube of metal with a volume of 89 mL?
Answer:
density = 7.02 g/mL
Explanation:
density is mass over volume, just divide
d = 625 g/89 mL = 7.02 g/mL
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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PLS HELP MATCH CONVERSIONS!!!!!
1 km/1000 m
7.5 m to km
3.875 g to mg
1000 m/1 km
1 g/1000 mg
50 mL to L
7.5 L into mL
1000 mL/1L
750 km to m
1 g/1000 mg
0.3 mg
1 L/1000 mL
Sugar Dissolving
a
Chemical Change
b
Physical Change
Chemical change cuz you are adding another substance to your water which changes the molecular structure of the water.
Can pure water exist as a liquid at 110° C ? Why or why not?
According to forces of attraction and as boiling point is 100°C pure water cannot exist as a liquid at 110° C.
What are forces of attraction?Forces of attraction is a force by which atoms in a molecule combine. it is basically an attractive force in nature. It can act between an ion and an atom as well.It varies for different states of matter that is solids, liquids and gases.
The forces of attraction are maximum in solids as the molecules present in solid are tightly held while it is minimum in gases as the molecules are far apart . The forces of attraction in liquids is intermediate of solids and gases.
The physical properties such as melting point, boiling point, density are all dependent on forces of attraction which exists in the substances.
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Which of the following describes a disconfirmed hypothesis?
it has been proven true
it has been poorly written and needs to be reformed
it has been proven false
it is not testable
Most Ancient Greek philosophers discusses the world around them but did not do any experiments or make detailed observations
Answer:
Because to them it was just a little bit of fiction. so they don't really think it's necessary to do experiments or make detailed observation
Explanation:
it's just like how we presently today discuss about robot talking to us like humans but it's not yet come to pass .
Explain what is meant by a weak acid
Answer:
A weak acid is an acid which dissociates partially to release few hydrogen protons or ions
Explanation:
[tex].[/tex]
If you burn a citronella candle near your picnic will it keep mosquitoes away
Answer:
Thanks!!!
Explanation:
Answer:
true
Explanation:
what are fossil fuels?
A fossil fuel is a natural substance formed from the buried remains of ancient organisms that can be used as a source of energy. Fossil fuels formed over millions of years as heat and pressure from layers of sediment changed the decayed organic remains into materials such as coal and petroleum.
How are they made?Fossils fuels are usually made of fossilized plant and animal remains from millions of years ago. The creation of fossil fuels—either oil, natural gas, or coal—from these fossils is determined by the type of fossil, the amount of heat, and the amount of pressure which they bore.
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The burning of a magnesium ribbon is an example of a reaction producing a metal oxide.
a) What reactants are required to production of a metal oxide?
b) Write a general equation for the production of a metal oxide.
Answer:
a) When the magnesium metal burns it reacts with oxygen found in the air to form Magnesium Oxide. A compound is a material in which atoms of different elements are bonded to one another. Oxygen and magnesium combine in a chemical reaction to form this compound. After it burns, it forms a white powder of the magnesium oxide.
b) Metals react with oxygen in the air to produce metal oxides. For example, magnesium reacts with oxygen to produce magnesium oxide when it is heated in air: magnesium + oxygen → magnesium oxide 2Mg + O2 → 2MgO
Explanation:
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Why are intensive properties useful for identifying a substance
Answer:
Intensive properties can be used to help identify a sample because these characteristics do not depend on the amount of sample, nor do they change according to conditions.
HOTS
A container made of same metal when exposed to
humid climate develops green coating.
Identify the metal. Give reason for both a & b.
How many moles of magnesium bromide are formed when 3.0 moles of magnesium reacts with 2.0 moles of bromine?
Mg+Br2 -> MgBr2
Answer:
Explanation:
Hello there, I think this is a limiting agent question.
When 3 moles of Mg is reacted with 2 moles of Br2, because of ratio, we just need 1.5 moles of Br2, so Mg is a limiting agent.
So 3 moles of Mg will make 3 moles of MgBr
Answer:
Use the given functions to set up and simplify
Mg+Br2→MgBr⋅2.
3=
2=
Mg+Br2→gBr⋅2=r2B+gM→MgBr⋅2
Explanation:
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The bond formed between two nonmetal atoms is called a(n) bond. This type of bond arises from the net attraction between the of each atom and the electrons of the other, and results in electrons being between the two atoms. Listen to the complete question
Answer: Covalent
Explanation: By definition, covalent bonds are those in which the shared electrons are shared greater than 50% of the time between two atoms.