when did democritus contribute to the atomic theory

Answers

Answer 1

Answer:

Around 400 B.C.E., the Greek philosopher Democritus introduced the idea of the atom as the basic building block matter.

Explanation:

Hope this helps.


Related Questions

what is the potential energy of a 3 kg box lifted to 12.5 meters high?​

Answers

Answer:

367.5 J

Explanation:

The potential energy of a body can be found by using the formula

PE = mgh

where

m is the mass

h is the height

g is the acceleration due to gravity which is 9.8 m/s²

From the question we have

PE = 3 × 9.8 × 12.5 = 367.5

We have the final answer as

367.5 J

Hope this helps you

Which of the operations results in sublimation?​

Answers

Answer:

hrjfnd

Explanation:

hfhdhfujduejdjdjdbfudbdjdbdifhdudjdufb

Inside the box is a list of endangered animals in the Philippines. Group the animals in three ways and make a diagram of your groupings in the space below.

Answers

The middle row! Im sure this would be correct! (please mark this brainly)

What was the ratio in the formula for Iron (II)
oxide?
lete
What was the ratio in the formula for Iron (III)
oxide?
DONE

Answers

Answer:

In Iron (II) oxide, ratio is 1:1

In iron (III) oxide, ratio is 4:2

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In Iron (II) oxide, ratio is 1:1

What is the importance of iron oxide?

Iron oxides are very important components in most soils as they have major influence on chemical, physical, and microbial properties of soils. Because of their nanoparticulate size (usually 5-200 nm), iron oxides possess large specific surface area.

Generally, iron oxides are prevalent, widely used as they are inexpensive, and play an imperative role in many biological and geological processes. They are also extensively used by humans, eg, as iron ores in thermite, catalysts, durable pigments.

When iron is exposed to moisture or oxygen, oxidation occurs. During this chemical reaction, iron is converted into iron oxide. The iron oxide typically has a reddish, flaky appearance that becomes progressively worse over time.

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which method is used to separate salt form salt solution

Answers

Explanation:

As we know, salt and water have different boiling points. Hence, we can use the "evaporation" technique to separate salt from salt solution. For this, one has to simply heat the salt solution till all the water boils and evaporates, and salt is left behind.

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Compared to the atomic radius of sodium, the atomic radius of argon is smaller. This is a result of

Answers

The atomic radius of the elements decreases from sodium to argon. This is because the number of protons increases (sodium has 11, argon has 18) so the nuclear charge

The atomic radius of Argon is smaller than the atomic radius of sodium because the effective nuclear charge increases as we move left to right in a period.

What is the atomic radius?

The atomic radius can be described as the shortest distance between the center of the nucleus of the atom and the outermost shell of the atom. An atomic radius can also be defined as half the distance between two atoms of the same element bonded together.

In general, the atomic radius of an atom reduces as we move from left to right in a period on the periodic table because while moving from left to right in a period, there is an increase in the effective nuclear charge. In periods, the valence electrons enter in the same outermost shell.

The atomic radius of atom increases when we move down a group because of the addition of a new principle shell.

Sodium is present at beginning of the third period and the Argon is present at the end of the same period. Therefore, Argon experiences a more effective nuclear charge than sodium so it has a smaller atomic radius.

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Does sodium (Na) and argon (Ar) on the periodic table have similar properties? Explain in terms of location on the periodic table

Answers

Sodium (Na) and Argon (Ar) on the periodic table does not have similar properties.

PERIODIC TABLE:

Periodic table is the organized table that showcases the position of elements. The periodic table is organized into groups and periods.

Groups of the periodic table is in a vertical format labeled 1 - 7 while the period is in a horizontal format labeled 1 - 7.

Elements in the same group have the same number of valence electrons and hence, possess similar chemical properties.

Sodium (Na) belongs to group 1 while argon is a noble gas, hence, they are not in the same group of the periodic table and cannot have same properties.

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which of the following is a physical property of the salt crystals shown here?
A.they are gas
B.they cannot burn
c.they are a liquid
D. they are clear white

Answers

yelyddlusheypupdldphdpdupdosigsogsg

Answer:

As the explanation i think the answer is D

Explanation:

Transparent and colourless in crystalline form – rather like ice. Crystallises in the isometric system, usually in the form of cubes. Soluble in water (35.6g/100g at 0°C and 39.2g/100g at 100°). Slightly soluble in alcohol, but insoluble in concentrated hydrochloric acid.Physical properties: Sodium chloride is a white crystalline solid with a density of 2.16 g/mL, and a melting point of 801 °C. It is also available as aqueous solutions of different concentrations, called saline solutions. Chemical properties: Sodium chloride is readily soluble in water and other polar solvents.

write short notes on the following:1. Analytical chemist 2. Chemical engineer 3. Healthcare scientists 4. Forensic scientist 5. Research scientist 6. Toxicologists 7. Pharmaceutical chemist 8. Nuclear chemist 9. Industrial chemist.​

Answers

Analytical chemistry studies and uses instruments and methods used to separate, identify, and quantify matter. In practice, separation, identification or quantification may constitute the entire analysis or be combined with another method. Separation isolates analytesChemical engineers use chemistry and engineering to turn raw materials into usable products, such as medicine, petrochemicals, and plastics on a large-scale, industrial setting. They are also involved in waste management and research. ... They may be involved in designing and constructing plants as a project engineer.A healthcare scientist or medical scientist is a scientist working in any of a number of health related disciplines. Healthcare scientists may work directly for health service providers, or in academia or industry. Forensic science, also known as criminalistics, is the application of science to criminal and civil laws, mainly—on the criminal side—during criminal investigation, as governed by the legal standards of admissible evidence and criminal procedure. Research scientists are responsible for designing, undertaking and analysing information from controlled laboratory-based investigations, experiments and trials. You could work for government laboratories, environmental organisations, specialist research organisations or universities.Toxicology is a scientific discipline, overlapping with biology, chemistry, pharmacology, and medicine, that involves the study of the adverse effects of chemical substances on living organisms and the practice of diagnosing and treating exposures to toxins and toxicants. A medicinal or pharmaceutical chemist researches and creates chemical compounds for use as drugs. By applying chemical research techniques to isolate natural healing agents or develop artificial ones, these chemists play a vital role in the pharmaceutical industry.Nuclear chemists conduct basic, applied, or theoretical research. They often work in laboratories and may be responsible for operating, maintaining, and repairing state-of-the-art instrumentation.Some industrial chemists work to improve product efficiency or to create better building materials, plastics, textiles, or petroleum products. They may help to set new industry standards, improve production techniques, and increase the effectiveness of various chemical processes.

What is the molality of a solution containing 10.0 G of NA2 S04 and 1000.0 G of water

Answers

Explanation:

1 literThe total of water is equal to 1000.0 g of water

we need to find the molality of a solution containing 10.0 g of dissolved in  Na₂S0₄1000.0 g of water

1. For that find the molar mass

Na:  2 x 22.99= 45.98

S:  32.07

O:  4 x 16= 64

The total molar mass is 142.05

We have to find the number of moles, y

To find the number of moles divide 10.0g by 142.05 g/mol.

So the number of moles is 0.0704 moles.

For the molarity, you need the number of moles divided by the volume. So, 0.0704 mol/1 L.

The molarity would end up being 0.0704 M

The molality of a solution containing 10.0 g of Na2SO4 dissolved in 1000.0 g of water is  0.0704 Mliter

How do anion formation and valence electrons relate?

Answers

Answer:

Atoms gain valence electrons to form anions.

Explanation:

mass=35g, density=5g/cm3. what is the volume?

Answers

Answer:

7 cm^3

Explanation:

Density = Mass/Volume

5 = 35/x

multiply both sides by x to get

5x = 35

then divide by 5

so x = 7 cm^3


The figure above shows two closed containers. Each contains the same volume of acetone in equilibrium with its
Yanar at the same temperature. The vapor pressure of the acetone is

Answers

The vapor pressure of a liquid and the prevailing atmospheric pressure,

determines the boiling point temperature.

The vapor pressure of the acetone is the same in both containers because

the temperature is the same.

Reasons:

The vapor pressure of a liquid is the pressure at which the number of

molecules entering the gaseous phase are in (dynamic) equilibrium with

the number of molecules entering the liquid phase.

The factors that affect vapor pressure are;

The type of molecules that make up the liquid or solidThe temperature of the liquid or solid

Changing the surface area changes the instantaneous concentration of

molecules of vapor above the liquid, however, an equilibrium vapor

pressure is reached with time as more molecules enter or exits the liquid

(or solid) due being over or under saturated.

Therefore, the surface area of the liquid has no effect on a liquid's vapor

pressure therefore;

The vapor pressure in both containers will be the same because the temperature is the same.

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how many bonding and non bonding domains are on the central atom in NH2-​

Answers

1bonding and 3non-bonding

(Refer to the attachment for structure

What forms a weak acid?
(Hint: Carbonation)

A) carbon dioxide/iron

B) carbon dioxide/water

C) carbon dioxide/materials

D) Oxygen/rust

Answers

I think its A). Carbon dioxide/iron
Weak acids form when there isn’t enough polarity between the hydrogen atom and the other atom in the bond to allow for easy removal of the hydrogen ion. Another factor that affects the strength of a acid is the size of the atom bonded to hydrogen


A car moves with a velocity of 15 m/s west for 3 seconds. Then, the
car moves with a velocity of 15 m/s east for 1 second. What is the
total displacement of the car?

Answers

Answer:

450 metre

Explanation:

VELOCITY = DISPLACEMENT /TIME TAKEN. THEREFORE THE DISPLACEMENT = 450 M.

Explanation:

What element has the electron configuration 1s22s22p63523p64523d4?
A.Chromium (Cr)
B.Magnesium (Mg)
C.Manganese (Mn)
D.Iron (Fe)

Answers

Answer:

B.Magnesium(Mg)

Explanation:

maybe

What volume of hydrogen gas forms if 10.0 g of Zn reacts at STP?

Answers

Answer:

0.690 liters is the volume of hydrogen gas produced if 2.00 grams of zinc is used with an excess of hydrochloric acid.

Explanation:

Zn(s)+2HCl(aq)\rightarrow ZnCl_2(aq)+H_2(g)Zn(s)+2HCl(aq)→ZnCl2(aq)+H2(g)

Mole so zinc = \frac{2.00}{65 g/mol}=0.03077 mol65g/mol2.00=0.03077mol

According to reaction, 1 mole of zinc gives 1 mole of hydrogen gas.

Then 0.03077  mole of zinc will give :

\frac{1}{1}\times 0.03077 mol=0.03077 mol11×0.03077mol=0.03077mol of hydrogen gas

Pressure of hydrogen gas ,P= 1 atm

Temperature  of of hydrogen gas ,T= 273.15 K

Volume of hydrogen gas = V = ?

Moles of hydrogen gas = 0.03077 mol

PV = nRT (Ideal gas equation )

V=\frac{nRT}{P}=\frac{0.03077 mol\times 0.0821 atm L/mol K\times 273.15 K}{1 atm}V=PnRT=1atm0.03077mol×0.0821atmL/molK×273.15K

V = 0.690 L

This image shows electronegativities of elements on the periodic table. Based on this information, which element is most likely to form a strong ionic bond and take on electrons?

(1 point)

helium (He)

cesium (Cs)

fluorine (F)

hydrogen (H)

Answers

Answer:

The answer is C. Fluorine.

why does it smell like burning when i turn my heat on?

Answers

Answer:

your lightbulb is mot likely burnt out

Explanation:

suppose that hypothetical element Jovian occurs as three isotopes with mass numbers 44, 46, and 48 respectively. If, in nature, Jovian occurs as Jovian-44 approximately 22.4% of the time, and as Jovian-46 approximately 44.0% of the time, what is the best value to use as the atomic mass of Jovian?

Answers

Answer:

46.2 amu

Explanation:

The average atomic mass of an element can be determined using the percentage abundance and mass of its isotopes. The average atomic mass of the hypothetical element Jovian is 46.2 amu.

What is average atomic mass?

Most of the elements have two or more isotopes in nature with different percentage abundance and mass. The average atomic mass of the element is then calculated using the formula written below:

Average atomic mass = % abundance /100 × mass of isotope 1  +  % abundance /100 × mass of isotope 2 + .....

Given the mass % abundance of Jovian -44 = 22.4 %

Jovian- 46 = 44 %

Jovian -48 = (100 - (44 + 22.4)) = 33.6 %

Average atomic mass of Jovian  =  ( 22.4 /100 × 44 ) +  ( 44 /100 × 46) +  ( 33.6  /100 × 48 ) = 46.2 amu

Therefore, the average atomic mass of the hypothetical element is 46.2 amu.

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Although a scientific theory is well supported and widely accepted, what might cause it to change? HELPPP
a new evidence
b scientific law
c indivial claim
D a scientific model

Answers

although a scientific theories will support and wildly excepted, what might cause of the change?

the answer would be A, New Evidence.

Answer:

d

Explanation:

How many Atoms are in H2COCH? Need asap pleassseee!

Answers

There is a total of 12, wish you luckkkkkkkk

Someone pls help me I will make you brain

Answers

Answer:

lll and ll

Explanation:

What volume (in L) of 1.10 M FeCl₃ would be required to obtain 0.700 moles of Cl⁻ ions?

Answers

0.636 liters of the 1.10 M FeCl₃ solution to obtain 0.700 moles of Cl⁻ ions.

Thus, Volume (L)=  moles/ concentration.  0.700 moles of Cl⁻ ions and the concentration of the FeCl₃ solution is 1.10 M, you can plug in these values to calculate the volume.

Volume (L) = 0.700/ 1.10 M,

Volume (L)=  1.10M/ 0.700moles

Volume (L) = 0.700/ 1.10 ≈ 0.636 L

Therefore, approximately 0.636 liters of the 1.10 M FeCl₃ solution to obtain 0.700 moles of Cl⁻ ions.

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HELP PLEASE I HAVE A TEST TODAY AND I DON'T UNDERSTAND ANY OF THIS...
265 kilojoules of energy are added to 150g of ice at 0 degrees C how many grams of water would boil away

Answers

Answer:

About 67 grams or 67.39 grams

Explanation:

First you would have to remember a few things:

 enthalpy to melt ice is called enthalpy of fusion.  this value is 6.02kJ/mol

  of ice  

 it takes 4.18 joules to raise 1 gram of liquid water 1 degree C

 water boils at 100 degrees C and water melts above 0 degrees C

 1 kilojoules is 1000 joules

  water's enthalpy of vaporization (steam) is 40.68 kJ/mol

  a mole of water is 18.02 grams

  we also have to assume the ice is at 0 degrees C

Step 1

Now start with your ice.  The enthalpy of fusion for ice is calculated with this formula:

q = n x ΔH    q= energy, n = moles of water, ΔH=enthalpy of fusion

Calculate how many moles of ice you have:

150g x (1 mol / 18.02 g) = 8.32 moles

Put that into the equation:

q = 8.32 mol x 6.02 = 50.09 kJ of energy to melt 150g of ice

Step 2

To raise 1 gram of water to the boiling point, it would take 4.18 joules times 100 (degrees C)  or 418 joules.

So if it takes 418 joules for just 1 gram of water, it would take 150 times that amount to raise 150g to 100 degrees C.  418 x 150 = 62,700 joules or 62.7 kilojoules.

So far you have already used 50.09 kJ to melt the ice and another 62.7 kJ to bring the water to boiling.  That's a total of 112.79 kJ.

Step 3

The final step is to see how much energy is left to vaporize the water.

Subtract the energy you used so far from what you were told you have.

265 kJ - 112.79 kJ = 152.21 kJ

Again q = mol x ΔH (vaporization)

You know you only have 152.21 kJ left so find out how many moles that will vaporize.

152.21 kJ = mol x 40.68  or   mol = 152.21 / 40.68  = 3.74 moles

This tells you that you have vaporized 3.74 moles with the energy you have left.

Convert that back to grams.

3.74 mol   x  ( 18.02 g / 1 mol ) = 67.39 grams

(b) A student states, "When the alcohol sample was at a temperature of 500 K, all the particles
were moving faster than any of the particles were moving at 400 K." Do you agree or disagree
with this student's statement? Justify your answer.
B
I
Submit
514
alel
(c) Using boxes like the ones below, draw three particle diagrams representing the sample of
alcohol cooling in this experiment. The diagrams should represent the sample at 3 minutes, 12
minutes, and 17 minutes.
Sign out
09:50

Answers

The kinetic energy of particles depends on temperature. As temperature increases, the kinetic energy of particles increases.

Temperature is defined as a measure of the average kinetic energy of the molecules of a substance. The higher the temperature of a substance the greater its kinetic energy.

From the foregoing, when the temperature is increased from 400K to 500K, greater kinetic energy is imparted to the molecules of the substance hence they move faster according to the kinetic theory of matter.

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During the process of peer review, a scientific study must have:
Group of answer choices (( its not precision//validity ))

repetition

precision

accuracy

validity

Answers

Answer:

Accuracy

I guess

Cause then it makes sense

Hope this helps

Is it possible to have an electromagnetic wave with a wavelength (a) of 104.68 m and an energy of 3.25 x 10-27 J? Show your work.

Answers

2. You work for an environmental company as an environmental toxicologist and have been hired to determine the contaminant present in a local resident’s pool. Create a flow chart outlining how you would detect the possible presence of Fe2+ and/or Sr2+

Which equation is balanced?

A) A

B) B

C) C

D) D

Answers

Answer:

All of them are equal cause they both have the same sign

Explanation:

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