what is true about chemicals?
A. Chemicals are rarely found on earth
B. Chemicals are never dangerous
C. Chemicals are in many substances in a home
D. Things containing chemicals always cost a lot of money

Answers

Answer 1

hi <3

i believe the correct option would be C

hope this helps :)


Related Questions

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

Answers

Answer:

option B is the right answer it helps in transfer of food.

Marta wants to explain how pollution is affecting the biodiversity of a local lake. Which of the following models are most appropriate options to use in her explanation? I. Graph II. 3-D model III. Simulation

Answers

Answer:

Graph models are most appropriate options to explain how pollution is affecting the biodiversity of a local lake.

Explanation:

Marta wants to explain how pollution is affecting the biodiversity of a local lake

For explanation

we have to use the graph because graph only shows the gradual level of of pollution that affect the biodiversity of a lake and water resources.

3D model and simulation is also effective but graph model is is more effective than other

To learn more about pollution refer:

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Most Ancient Greek philosophers discusses the world around them but did not do any experiments or make detailed observations

Answers

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 .

A student is investigating potential and kinetic energy by stretching a spring across a table
At which step is the potential energy in the spring the greatest

Answers

Answer: when it’s fully stretched across the table

Explanation: because when it’s stretched it has the most potential kinetic energy

If you burn a citronella candle near your picnic will it keep mosquitoes away

Answers

Answer:

Thanks!!!

Explanation:

Answer:

true

Explanation:

IF U ANSWER ILL BRAINLIST AND GIVE U 5 STAR PLUS U GET EXTRA POINTS:)) WRITE IT IN UR OWN WORDS PLS OR NO POINTS.

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.

Answers

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:

Hope it helps. if yes, plz mark me as brainliest

state two application of chemistry on each of the following:-
1.forensic
2.agriculture
3.industrial
4.millitary
5.space science​

Answers

1 - Identifying substances & analysing evidence

2 - Raw products in food and drink & environmental monitoring

3 - Safe machinery & safe chemical usage

4 - Bulletproof materials & machinery

5 - Oxygen monitoring & gravity training

Pls give me a brainliest if this helped thx

If you were converting from Milli- to Centi- units, how many decimal places would you move?

Answers

Answer:

1 decimal place

Explanation:

centi- is 10 times larger than milli- (centi- = 0.01  milli- = 0.001)

1 mili is equal to the 0.01 centi. Since all metric units differ by powers of ten, changing between them just necessitates moving the decimal point to the left or right.

What is difference between millimeter and centimeter ?

The actual ratio is 10 millimeters to 1 centimeter. Now, it is clear that centimeters are bigger than millimeters.

There is no change in volume, these measurements are the same. The main distinction is that fluid quantities are measured in milliliters, but solid quantities are measured in cubic centimeters. 1 cc is 1 mL no matter what is being measured.

The units used to measure length are centimeters and millimeters, respectively. 1 cm is equivalent to 10 mm, and 1 millimeter is equal to 0.1 centimeter.

Thus, for converting from Milli- to Centi- units 10 digit place would be move.

To learn more about  millimeter and centimeter refer the link below;

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Explain what is meant by a weak acid

Answers

Answer:

A weak acid is an acid which dissociates partially to release few hydrogen protons or ions

Explanation:

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Define measurement. why is it important in our life?​

Answers

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.

name four states of matter​

Answers

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.

Help anyone can help me do this question,I will mark brainlest.​

Answers

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

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

Answers

It’s either not testable since hypothesis need to be able to be tested or it could be not likely tho second option it has been poorly written

what happens to concrete after heating it​

Answers

Answer: the cement inside becomes dehydrated losing some of its water as vapour. The water vapour begins moving away from the source of the heat but becomes trapped inside the structure of the concrete .

Circle the two terms in each group that are related. Explain how the terms are related.
16. Celsius degree, mass, Kelvin
17. balance, second, mass
18. kilogram, liter, cubic centimeter
19. time, second, distance
20. decimeter, kilometer, Kelvin

Answers

Answer:

16) Celsius degree and Kelvin are related since they are measuring unit of temperature.

(17) Balance and Mass are related since mass can be measured with balance.

18) Liter and cubic centimeters are related since they are used to measure capacity or volume of liquid.

19) time and second are related since time is measured in second

20) decimeter and kilometer are related since they are measuring unit of distance or displacement.

Explanation:

The two terms in each group that are related are Celsius and Kelvin, balance and mass, liter and cubic centimeter, time and second, and decimeters and kilometers.

What are Celsius and Kelvin?

Celsius and Kelvin are the units and they are related to each other because both of them can be used to determine or to define the temperature of the environment for anything which is needed to be measured.

The balance and mass are related to the balancing of mass and kilogram with centimeter cubic are related for density and time and second is related to each other last decimeters and kilometers unit of lengths.

Therefore, two terms in each group that are related are Celsius and Kelvin, balance and mass, liter and cubic centimeter, time and second, and decimeters and kilometers.

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stute 2 lomportance of weather fore castings​

Answers

Answer:

Climatology and Weather Forecasting is important since it helps determine future climate expectations.Forecasts based on temperature and precipitation are important to agriculture, and therefore to traders within commodity markets. Temperature forecasts are used by utility companies to estimate demand over coming days.

Explanation:

Climatology and Weather Forecasting is important since it helps determine future climate expectations. Through the use of latitude, one can determine the likelihood of snow and hail reaching the surface. You can also be able to identify the thermal energy from the sun that is accessible to a region.

Define uniform and non-uniform motion.​

Answers

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 !!

In the circular flow diagram, what do firms provide to product markets?(1 point)

Answers

Answer:

Firms produce goods and services,which they sell to households in return for revenue.

Answer: Goods and Services

Explanation:

who knows india??????​

Answers

Answer:

Me India is located in Asia and its capital name is New Delhi.

Explanation:

[tex]india \\ 1)india \: is \: the \: 7 \: th \: largest \: country \\ 2)home \: to \: old \: civilizations \\ 3)father \: of \: the \: nation \: mahathma \: gandi \\ 4)country \: is \: divided \: in \: to \: 28state \\ 5)1000of \: lnguages \: 100 \: of \: cultures \: \\ so \: india \: is \: very \: much \: attractive \\ very \: much \: special \\ 1947 \: august15 \: indias \: independce \: day \\ thank \: you \: \\ jai \: hind[/tex]

what are fossil fuels?​

Answers

Hi,

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.

Hope it helps....

(by Benjemin)

which of the folowing idead about thr atom changed when new evidence was discoverd

Answers

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.

as the amount of water decreases in a glass of water you are drinking the desitny of water also decreases true or false

Answers

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

Fractions of crude oil​

Answers

Answer:

Fractions. There are several ways of classifying the useful fractions that are distilled from crude oil. One general way is by dividing into three categories: light, middle, and heavy fractions. Heavier components condense at higher temperatures and are removed at the bottom of the column.

Answer:

Fraction: No. of carbon atoms: Boiling point range oC:

Gasoline (petrol) 4 - 12                   32-160oC

Kerosine (paraffin) 11 - 15            160-250oC

Diesel oil         15 - 19               220-350oC

Residue lubricating oil heavy fuel oil bitumen C Above 350oC

Explanation:

Fractions. There are several ways of classifying the useful fractions that are distilled from crude oil. One general way is by dividing into three categories: light, middle, and heavy fractions. Heavier components condense at higher temperatures and are removed at the bottom of the column

What do the nuclei of 1H hydrogen atoms contain?

protons only

electrons and protons

electrons and neutrons

neutrons only

Answers

Answer:

"Protons only"

Explanation:

Hydrogen has one proton in its nucleus. It does have one electron rotating outside of the nucleus, BUT NOT IN THE NUCLEUS. 'A' is the correct answer.

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.​

Answers

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 waves

The 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.

Learn more about photons here: https://brainly.com/question/18101137

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.

Answers

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.

Learn more: https://brainly.com/question/8834373

Plant and Animal Cells
С
B
F
1 20 points
Which letter represents the brain of the cell?
о B
H
H
Why
E
D
G

Answers

Answer:

Nucleus is known as the brain of the cell.

correct option is B letter

Why are intensive properties useful for identifying a substance

Answers

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.

grass → rabbit → fox

Explain why energy is lost by the rabbits in the middle step of this food chain.

Answers

Answer:

The rabbit losses energy by great and waste

Explanation:

The grass loses energy by respiration and a rabbit from eating other living organisms but when the fox eats the rabbit no if not little energy is passed to the fox

As a professor Daniel must complete a research project each year in order to
stay on staff. Daniel is an engineer and has to deal with many complicated
mathematical calculations. Knowing this fact Daniel would most likely concern
himself with qualitative research,

Answers

Explanation:

Add our site sources in order to be advantage of knowledge

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