The Greek philosopher Empedocles proposed the idea that
ALL matter was made of_____
elements.

Answers

Answer 1

Answer:

the four elements fire, air, water earth

Explanation:

Answer 2
All matter was made of Four elements

Related Questions

how many atoms in a chair

Answers

Answer:

100 trillion atoms are in one cell and  so just find how many cells are in a chair and then take 100xthe number and you get your answer

Explanation:

There are uncountable atoms which are present in a chair depending on it's size.

What is an atom?

An atom is defined as the smallest unit of matter which forms an element. Every form of matter whether solid,liquid , gas consists of atoms . Each atom has a nucleus which is composed of protons and neutrons and shells in which the electrons revolve.

The protons are positively charged and neutrons are neutral and hence the nucleus is positively charged. The electrons which revolve around the nucleus are negatively charged and hence the atom as a whole is neutral and stable due to presence of oppositely charged particles.

Atoms of the same element are similar as they have number of sub- atomic particles which on combination do not alter the chemical properties of the substances.

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PLS ANSWER!! ASAP!!! 10 POINTS!!
Why are metals in Group 1A so reactive?
A. These metals need one electron to complete their outer shell.
B. These metals need two electrons to complete their outer shell.
C. These metals have one electron in their outer shell.
D. These metals have two electrons in their outer shell.

Answers

Answer:

the answer is = a. these materials...

The metals of Group 1A are so reactive because these metals have one electron in their outer shell. Therefore, option (C) is correct.

What are the metals of Group 1A?

The elements of Group 1A of the periodic table are also called alkali metals. The seven elements of group 1 A include hydrogen(H), lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr).

These are low-melting, extremely reactive, glossy metals that oxidize when exposed to air. When dissolved in water, these metals or their oxides produce a basic solution. Because of their high reactivity, alkali metals are instead found as ionic compounds (except hydrogen).

The general electronic configuration of the alkali metals is ns¹. As they lose one electron from their valence shell they acquire the nearest noble gas configuration, therefore they are very reactive.

The alkali metals are all lustrous, soft, and extremely reactive metals at normal temperature and pressure that quickly lose their valence electrons to create cations with charge +1.

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The substances that get rid of carbamates and organophosphates are?​

Answers

Answer: Alfracon

...............................

Why does an ion have a charge
Help please:)

Answers

Answer:

An ion is charged because the number of electrons does not equal the amount of particles.

Explanation:

Can be positive (meaning more protons than electrons) and it can be negatively charged (meaning there are more electrons than protons).

Hope this helps!

Answer:

An ion has a charge because the number of electrons dont equal the amount of protons in the molecule or atom.

Explanation:

The negative or positive charge depend on wether the atom or molecule has more electrons(-) or protons(+).

What occurs to the particles in a fluid during convection ?

Answers

Answer: what are options

Explanation:

At every depth, soil composition remains the same.
O
True
O False

Answers

Answer:

false

Explanation:

Hope the answer was usefull for us

Answer:

false. there is the surface soil, which has a lot of partly decayed stuff, topsoil, which has minerals and organic material, subsoil, which is made from sand, silt, and clay that hasn't been broken down, and parent material, which is the place where not much living things live in, except for gigantic tree roots. then there is the bedrock, which is; you guessed it:rock entirely.

Explanation:

Which of the following presents the steps of the engineering process in the correct order?
1.Identify a need, make a plan know the background, do the work, test the results, evaluate and redesign
O
2. dentify a need, know the background, do the work, make a plan, evaluate and redesign, test the results
3. Know the background, identify a need, make a plan, evaluate and redesign, do the work, test the results
4.Identify a need, know the background, make a plan, do the work, test the results, evaluate and redesign

Answers

Answer:

4

Explanation:

I got it right

The engineering process in the correct order "Identify a need, know the background, make a plan, do the work, test the results, evaluate and redesign"

What is engineering process?

At an industrial level, process engineering is just the understanding as well as application of fundamental natural principles and laws that allow people to transform raw materials along with energy into products that seem to be beneficial to society.

What is redesign?

Redesign, in terms of building, is the procedure of finding a solution to such a project. this includes then writing instructions that allow such a solution to be built.

The engineering process in the correct order "Identify a need, know the background, make a plan, do the work, test the results, evaluate and redesign"

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What causes the
differences in physical characteristics like hair color among people?
1. diferent versions of genes
2. variations in DNA length
3. different numbers of chromosomes
4. variations in cell nucleus size



Answers

DNA
sorry if it’s wrong, but that answer seems reasonable

Answer:

b

Explanation:

i took the test

Explain what happens if the nucleus, of an atom, becomes unstable.

Answers

Answer:The unstable nucleus of radioactive atoms emit radiation. When this occurs, a new atom and element are formed. This process is called radioactive decay. It continues until the forces in the unstable nucleus are balanced.

Explanation:

Chromium-48 decays. After 6 half-lives, what fraction of the original nuclei
would remain?

Answers

Answer:

The fraction of original nuclei remaining is 1.5625

Explanation:

at room temperature oxygen gas travels at 393.5 meters per second. How fast does oxygen travel in mile per hour ?

Answers

Answer:

Oxygen travels in 1,416,600

Explanation:

An orange falls off of a display at a store and rolls 5 meters in 2.5 seconds. What is the average speed of the orange?

Answers

The orange moves at 2M/s
5/2.5=2
2meters/second

An orange falls off of a display at a store and rolls 5 meters in 2.5 seconds the average speed of the orange will be 2 meters per second.

What is speed?

Speed if the rate of change of position of an object in a given time of interval or per unit time of interval and it is the ratio of distance traveled to the time taken and the unit will be meter per second.

The average speed of the orange will be if the orange falls off of a display at a store and rolls 5 meters in 2.5 seconds,

               Speed = distance / time

Substituting the value,

    speed =5 meters /2.5 seconds

    speed = 2 meters per second.

Therefore, the average speed of the orange will be 2 meters per second if, the orange falls off of a display at a store and rolls 5 meters in 2.5 seconds.

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Element X has two natural isotopes. The isotope with a mass of 10.012 amu (10X) has a relative abundance of 19.91%. The isotope with a mass of 11.009 ammu (11X) has a relative abundance of 80.09%. Calculate the atomic mass of this element.

Answers

Answer:

10.81

Explanation:

you can see the answer at the pic

How many electrons are there in the only energy level of helium, a noble gas? * Two Three Six Eight​

Answers

Answer:

Explanation:

Noble gases are the least reactive of all known elements. That's because with eight valence electrons, their outer energy levels are full. The only exception is helium, which has just two electrons.

how to check atomic mass?​

Answers

Answer:

There are multiple ways to check mass but I'll tell you one. Look below

Explanation:

One easy way of checking atomic mass is by adding protons and neutrons.

For example:

We have 5 protons and 4 neutrons.

5+4=9

I hope this helps (:

marine science flvs 2.03
can someone please send the answers for this!!!

Answers

Answer:

101

Explanation:

Answer:

 

Explanation:

WHOEVER ANSWERS THIS QUESTION FIRST WILL GET BRAINLIEST!!
PLEASE HURRY!!!

Select 5 elements that form ions in an isoelectronic series with the noble gas Argon. Support your claim with evidence and scientific reasoning.

Answers

Answer:

                           

Explanation:

                                 

What do we call the bond that forms when atoms share two pairs of electrons
(I have a test tomorrow and I'm doing a review right now but have no idea what the answer to this is.)

Answers

a covalent bond (also called a molecular bond)

How many neutrons make up one of these potassium atoms?

Answers

Potassium has twenty neutrons

Answer:

20

Explanation:

what is the mass of a 7.91 cm cubed piece of lead having a density of 11.34 g/cm cubed

Answers

Answer:

The answer is 89.70 g

Explanation:

The mass of a substance when given the density and volume can be found by using the formula

mass = Density × volume

From the question

density = 11.34 g/cm³

volume = 7.91 cm³

We have

mass = 11.34 × 7.91 = 89.6994

We have the final answer as

89.70 g

Hope this helps you

How many meters is a 50 yards olympic size swimming pool?

Answers

Answer:

An official Olympic Sized pool is 50 meters long by 25 meters wide.

Explanation:

Describe the relationship between an element and a compound.

Answers

Answer:

An element is a material that consist of a single type of atom . each atom type contains same number of protons . chemical bonds link elements to form more complex molecules called compound A compound consist of two or more elements held together by covalent or ionic bonds.

are you clear?

Answer question number 4

Answers

Answer: Choice A

Explanation:

A scientist is examining a mixture of nitrogen, hydrogen, and ammonia. The individual pressures that are exerted by nitrogen and hydrogen are 0.26 atm and 0.28 atm, respectively. If the total pressure is 0.90 atm, what is the partial pressure of ammonia? Use P subscript T equals P subscript 1 plus P subscript 2 plus P subscript 3 plus ellipses plus P subscript n.. 0.27 atm 0.36 atm 0.54 atm 0.90 atm

Answers

Answer:  0.36 atm

Explanation:

According to Dalton's law, the total pressure is the sum of individual pressures.

[tex]p_{total}=p_1+p_2+p_3[/tex]

Given :  [tex]p_{total}[/tex] = total pressure of gases = 0.90 atm

[tex]p_{N_2}[/tex]= partial pressure of nitrogen =  0.26 atm

[tex]p_{H_2}[/tex] = partial pressure of hydrogen = 0.28 atm

[tex]p_{NH_3}[/tex]= partial pressure of ammonia = ?

putting in the values we get:

[tex]0.90=0.26 +0.28+p_{NH_3}[/tex]

[tex]p_{NH_3}=0.36atm[/tex]

Thus the partial pressure of ammonia is 0.36 atm

Answer:

B) 0.36 atm

Explanation:

Which of the following is an example of how pictures of a planet's surface can provide evidence about the planet's natural resources?

Answers

Answer:

it can show how much green is left. and how climate change is going, and the cloud shows how much oxygen is left in the air.

Why are small quantities of chlorofluorocarbons so harmful to the ozone layer? a. The chlorofluorocarbons act like ultraviolet radiation causing large amount of ozone to be produced. b. The chlorine from the chlorofluorocarbons reacts with free molecules of oxygen causing a stop in ozone production. c. Free oxygen atoms can replace the chlorine in chlorine monoxide, releasing a free atom of chlorine which can then recombine with an oxygen atom in ozone, destroying more ozone. d. Chlorofluorocarbons absorb ultraviolet radiation, preventing the formation of ozone.

Answers

Answer:

Why are small quantities of chlorofluorocarbons so harmful to the ozone layer?  Free oxygen atoms can replace the chlorine in chlorine monoxide, releasing a free atom of chlorine which can then recombine with an oxygen atom in ozone, destroying more ozone.

Explanation:

The statement for small quantities of chlorofluorocarbons so harmful to the ozone layer is "Free oxygen atoms can replace the chlorine in chlorine monoxide, releasing a free atom of chlorine which can then recombine with an oxygen atom in ozone, destroying more ozone."

What is ozone layer?

The ozone layer is a thin layer of air in the Earth's atmosphere that absorbs nearly all of the sun's damaging UV radiation.

What is CFCs?

CFCs (chlorofluorocarbons) are harmless and nonflammable compounds made up of carbon, chlorine, and fluorine atoms.

The earth's protective ozone layer is destroyed by chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), and halons, which shield the earth from damaging ultraviolet (UV-B) rays released by the sun. CFCs and HCFCs also warm the earth's lower atmosphere, causing global climate change.

When some substances are exposed to high UV radiation in the stratosphere, they emit chlorine or bromine. Ozone-depleting chemicals are compounds that contribute to ozone depletion (ODS). Chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), carbon tetrachloride, and methyl chloroform are examples of ODS that produce chlorine. Halons and methyl bromide are two ODS that emit bromine.

Because there isn't much ozone in the atmosphere, what little there is is critical for protecting the Earth's surface from excessive UV light from the Sun. It turns out that it reacts with chlorine, which means that chlorine effectively eliminates ozone.

When the chlorine in CFCs combines with ultraviolet light, it releases chlorine, which then reacts with ozone, reducing the protection humans get from ultraviolet light, allowing more CFCs to release chlorine, and so on. Multiple ozone molecules will interact with one free chlorine atom, which is free because UV light has hit the CFC molecule. As a result, the damage it can cause is likely to be significantly more than you might imagine.

Hence the correct option is c.

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Type the correct answer in each box.

Which chemical symbols will complete the equation for this single displacement reaction?

2NaBr + Cl2 → 2 __ __ + __ 2

Answers

Answer:

2Naci+Br2

Explanation:

i hope it is help full

Answer:

Na//Cl//Br

Explanation:

According to Dalton’s atomic theory, what are elements and what makes one element different from another?

Answers

Dalton was a chemist who discovered the “law of multiple proportion” in chemical reaction in early nineteenth century. For example, element of tin, he observed, interacted with oxygen to produce two different masses but in proportion 1:2. (Now, this is known to correspond to the formation of tin-monoxide and tin-dioxide, with one and two atoms of oxygen, respectively.)

From such and related studies, he proposed his theory of chemical elements: (a) that all elements are composed of ‘atoms’, the hypothetical indivisible constituents of matter of the ancient Greek thinkers, like, Democritus, and (b) that the elements differ from one another due to the atoms of different masses and sizes that constitute an element.

The modern theory of chemistry says that an element consists of an atom that consists of a heavy nucleus with positively charged ‘protons’ (and most often also the neutral particles called ‘neutrons’) at its center and, an equal number of negatively charged (and much lighter) ‘electrons’, distributed around it in discrete energy shells. Further, the elements differ from one another by the number of positively charged protons in their nucleus, the so-called atomic number, Z, of an atom. Finally, molecules are formed as well as chemical reactions take place, through the exchange or transfer of the electron(s) in the outermost shells of the reacting atoms (and/or molecules).

Mr. Hackworth toasts a marshmallow over a fire. The outside of the marshmallow turns black, a new substance with new properties is created on the outside of the marshmallow, and the marshmallow gives off an odor. What type of change occured?

A
Physical, because color is a physical property.

B
Physical, because a new substance was created, smell, and color change.

C
Chemical, because a new substance was created, smell, and color change.

D
Chemical, because color is a chemical property.

Answers

Answer:

C

Explanation:

This is a chemical property because a catalyst is added(fire). Without a catalyst a marshmallow would stay a marshmallow. The sugar caramelizes(this is not physical because sugar is burning)

In this chemical formula: 3NH4 (ammonium) This chemical formula means there are 3 _____________ ___________, and 4 __________ ________ in each molecule.

Answers

Answer:

hope it helped you

Explanation:

3 atoms of nitrogen and 4 atoms of hydrogen in each molecule

The chemical formula 3NH4 means there are 3 atoms of nitrogen and 4 atoms of hydrogen in each molecule.

What are chemical reaction?

Chemical reaction is defined as a process in which one or more substances, the reactants, are converted into one or more different substances, the products.

A chemical reaction rearranges the constituent atoms of the reactants to create different substances as products.

There are five main types of reactions.

Combination reaction - A combination reaction is a reaction in which two or more substance combine to form a single new substance also known as synthesis reaction.Decomposition reaction - A decomposition reaction is a reaction in which a compounds break down into two or more simpler substance.Single replacement reaction - A single replacement reaction is a reaction in which one element replaces a similar element in a compound.Double replacement reaction - A double replacement reaction is a reaction in which the positive or negative ions of to ionic compounds exchange places from two new compound.Combustion reaction - A combustion reaction is a reaction in which a substance reacts with oxygen gas, releasing energy in the form of heat and light.

Thus, the chemical formula 3NH4 means there are 3 atoms of nitrogen and 4 atoms of hydrogen in each molecule.

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what is 1x7791789x79188037891883+8904781982994 Which object is being acted on by balanced forces?Group of answer choicesa car that moves at a constant speed in one directiona baseball that rolls to a stop in a fielda skateboard that rolls increasingly faster down a hilla snowflake that falls and lands on a roof Write the equation of the line that passes through the given points.(0,4) and (5,10) Which pairs of numbers have a greatest common factor of 9 Which line from Narrative of the Life of Frederick Douglass provides evidence that enslaved persons were treated violently?Thus, after an absence of three years and one month, I was once more permitted to return to my old home at Baltimore. The fact was, we cared but little where we went, so we went together.Upon the whole, we got along very well, so far as the jail and its keeper were concerned.My master sent me away, because there existed against me a very great prejudice in the community, and he feared I might be killed. For the AP axial projection of the first carpometacarpal joint, the central ray is placed at a _____ angle toward the forearm. 1.) An object exerts a force of 10 lb on an area of 2 square inches. What is the pressure theobject exerts on the surface? Where are you most likely to find ligaments in the body?A joints between long bonesB joints between two or more irregular bonesC joints between a long bone and a short boneD joints between muscles and bones How many different four-digit alarm codes can be formed for a house alarm ifdigits cannot be repeated? simplify show your work PLEASE HELP!!!There are 800 students who attend Park Middle School. There are 1.5 times as many boys as there are girls. Assign variables to the unknowns. 93% of a arabs belong to which ethnic group? Actually who can help with ww1 history its due in an hour Which percentage of the Middle Atlantic people work in manufacturing?25%33%50%66%PLZ HELPPP!!!!:-[ Most African farmers _____. Have given up the rural life and moved to cities to work in factories choose to grow cash crops because there are no risks involved are successful because they have plenty of land and tools struggle because their land has poor soil and receives little rain Which document guarantees individual freedoms such as peaceful assembly and a speedy trial? A.the U.S. Bill of Rights B. the Maryland Toleration Act C.the U.S. Declaration of Independence D.the Virginia Statute for Religious Freedom Write two hundred twenty-two and six thousand five hundred seventeen ten-thousandths as a decimal number. PLEASE HELP BEFORE 4 PM!!!1. 641 divided by 432. 4684 divided by 273. 6455 divided by 64 Read this excerpt from Through the Looking-Glass by Lewis Carroll.This sounded nonsense to Alice, so she said nothing, but set off at once towards the Red Queen. To her surprise, she lost sight of her in a moment, and found herself walking in at the front-door again.A little provoked, she drew back, and after looking everywhere for the queen (whom she spied out at last, a long way off), she thought she would try the plan, this time, of walking in the opposite direction.It succeeded beautifully. She had not been walking a minute before she found herself face to face with the Red Queen, and full in sight of the hill she had been so long aiming at.Why does Alice need to walk in the opposite direction to get to the Red Queen?because the Red Queen has moved to another locationbecause Alice is initially walking in the wrong directionbecause the house has changed the location of its windows and doorsbecause in this land the opposite way of doing things is often the correct way what molecule is this?