Who first proposed the idea of the atom

Answers

Answer 1

Answer:

it's John Dalton

Explanation:

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Answer 2
John Dalton formulated the first modern description of it as the fundamental building block of chemical structures.

Related Questions

10 advantages of atomic absorption spectrometer over flame photometer​

Answers

Answer:

(1) It does not suffer from spectral interference, which occurs in flame emission spectroscopy.

(2) By atomic absorption technique, traces of one element can easily be determined in presence of high concentration of other elements.

The technique makes use of the atomic absorption spectrum of a sample in order to assess the concentration of specific analytes within it. It requires standards with known analyte content to establish the relation between the measured absorbance and the analyte concentration and relies therefore on the Beer–Lambert law.

9. Hydrogen is 99% H, 0.8% ?H, and 0.2% H. Calculate its average atomic mass.


Answers

Answer:  Technically, this cannot be answered, since none of the H atoms have a mass number assigned.  With the assumption noted delow, I calculate 1.012 as the average atomic mass.

Explanation:

My answer is based on assumed masses for the three H isotopes:

1H :   1 AMU

2H:   2 AMU   Deuterium

3H:    3AMU   Tritium

     AMU   Rel Abund.    Wt. Avg

1H 1     99.00%      0.99

2H 2       0.80%      0.016

3H 3       0.20%       0.006

              Sum   1.012

soru sor.............................................

Answers

Answer:

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

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What are the differences of a physical change and a chemical change?

Answers

Answer:

a physical change only changes the look of something whereas a chemical change occurs when one thing has a reaction and it forms a new substance.

Can someone help me pls, I do not know how to do this. i am trying to help a friend as well​

Answers

Answer:

Your answer is 5 x 10

I hope it's helps you

Answer:

[tex]thank \: you[/tex]

How does the mass of each atom compare to the average atomic mass of the element give in the periodic table?

Answers

Explanation:

One is the average weight of an element and the other is the total number of nucleons in the atom's nucleus. Atomic mass is also known as atomic weight. Atomic mass is the weighted average mass of an atom of an element based on the relative natural abundance of that element's isotopes please mark as a brainliest

Water can act as both an acid and a base in an ionization reaction to form (H) and OH ions.
What is this phenomenon called?

Answers

amphoterism. amphoteric substance is a substance/compound that can act as both acid and base

Assuming equimolar quantities of reactants, which compound will react to the greatest extent with boron trifluoride (BF3) in a Lewis acid-base reaction

Answers

BF3 is considered as lewis acid because it’s the acceptor of electron

NH3 is an example of a Lewis Base that will react extensively with BF3 to form the compound BF3NH3

To solve such this we must know the concept of acid-base reaction. Therefore, NH[tex]_3[/tex] is the compound that will react to the greatest extent with boron trifluoride (BF[tex]_3[/tex]) in a Lewis acid-base reaction.

What is chemical reaction?

Chemical reaction is a process in which two or more than two molecules collide in right orientation and energy to form a new chemical compound. The mass of the overall reaction should be conserved. There are so many types of chemical reaction reaction like combination reaction, double displacement reaction.

NH[tex]_3[/tex] is an example of a Lewis Base that will react extensively with BF[tex]_3[/tex] to form the compound NH[tex]_3[/tex] + BF[tex]_3[/tex] → [B (NH[tex]_3[/tex])F[tex]_3[/tex]].

Therefore, NH[tex]_3[/tex] is the compound that will react to the greatest extent with boron trifluoride (BF[tex]_3[/tex]) in a Lewis acid-base reaction.

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Write the molecular formula of ferric oxide and calcium hydroxide by criss-cross method ​

Answers

Ferric Oxide:-

[tex]\setlength{\unitlength}{1cm}\begin{picture}(0,0)\thicklines\put(0,3){\bf Fe}\put(0,0){\bf -3}\put(4,3){\sf O}\put(4,0){\bf -2}\put(0.2,2.9){\vector(4,-3){3.5}}\put(3.8,2.9){\vector(-4,-3){3.5}}\end{picture}[/tex]

[tex]\\ \sf\longmapsto Fe_2O_3[/tex]

Calcium Hydroxide:-

[tex]\setlength{\unitlength}{1cm}\begin{picture}(0,0)\thicklines\put(0,3){\bf Ca}\put(0,0){\bf 2}\put(4,3){\sf OH}\put(4,0){\bf -1}\put(0.2,2.9){\vector(4,-3){3.5}}\put(3.8,2.9){\vector(-4,-3){3.5}}\end{picture}[/tex]

[tex]\\ \sf\longmapsto Ca(OH)_2[/tex]

Note:-

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How does convection affect the earths atmosphere

Answers

Answer:

I think the layers of the atmosphere does temperature increase with increasing height. It is affected by convection because it heats the lower atmosphere. It is affected by conduction because the is the transfer of thermal energy. I guess

Hope this help!

Describe the differences between models and scientific laws and theories. (

Answers

Answer:

Scientific laws and theories have different jobs to do. A scientific law predicts the results of certain initial conditions. ... In simplest terms, a law predicts what happens while a theory proposes why. A theory will never grow up into a law, though the development of one often triggers progress on

Explanation:

The reaction described by the equation X + Y Z
shown to have the following rate law:
R = K[X] [Y]
What is the effect on the rate if the concentration
of [X] is doubled and [Y] remains constant?

Answers

rate is doubled because Rate is proportional to the concentration of X

Determine the empirical formula of the compound formed when 1.2g of magnesium reacts with 3.55g of chlorine.Take the molar mass of magnesium and chlorine to be 24g and 35.5g respectively.

Answers

Explanation:

For Mg, (1.2 g Mg/24 g Mg) = 0.05 mol Mg.

For Cl, (3.55 g Cl/35.5 g Cl) = 0.1 mol Cl

So the ratio now is

Mg:Cl = 0.05 : 0.1 = 1:2

I got the 1:2 ratio by dividing both by the smallest number, which is 0.05 mol. Therefore, the empirical for formula of the substance is [tex]MgCl_2[/tex]

The empirical formula of the compound formed when magnesium reacts with chlorine is MgCl₂.

To determine the empirical formula of the compound formed when magnesium (Mg) reacts with chlorine (Cl), we need to find the ratio of the elements in terms of moles.

First, we calculate the number of moles of each element:

Moles of Mg = Mass of Mg / Molar mass of Mg

Moles of Mg = 1.2 g / 24 g/mol

Moles of Mg = 0.05 mol

Moles of Cl = Mass of Cl / Molar mass of Cl

Moles of Cl = 3.55 g / 35.5 g/mol

Moles of Cl = 0.1 mol

Next, we determine the simplest whole-number ratio between the moles of Mg and Cl:

Mg:Cl = 0.05 mol : 0.1 mol

To simplify the ratio, we divide both values by the smaller value (0.05 mol in this case):

Mg:Cl = 0.05 mol / 0.05 mol : 0.1 mol / 0.05 mol

Mg:Cl = 1 : 2

Therefore, the empirical formula of the compound formed when magnesium reacts with chlorine is MgCl₂.

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Things around you. All around you there is matter. The chair you are sitting on, air and
water are all matter. Almost everything that you see is matter. Anything that has mass
and takes up space is called matter.
What do we call something that has mass and takes up space?

Answers

Answer:

Hi Lovelys!!

Answers down below!!

Explanation:

There are two answer my me: Matter and Volume

Matter is anything that has mass and takes up space. Mass gives an object the property of weight and inertia (resistance to change in the motion of an object).

Volume simply refers to the space an object takes up. Depending on the physical state of an object, there are a couple ways to measure volume. If we are trying to measure the volume of a box, for instance, we would multiply the length of the box by its height and by its width.

Hope this helps!! =3

Have a wonderful day, evening, or night!! <3

How many bonds can a carbon atom form?
A. 3
O B. 4
C. 2.
O D. 1

Answers

Answer:

B)4

Explanation:

write any two effect of gravity​

Answers

The Earth's gravitational force accelerates objects when they fall. It constantly pulls, and the objects constantly speed up.

Part A
In the year 2012, an estimated amount of 31.6 billion metric tons (1 metric ton = 1000 kg) of carbon dioxide (CO2) was emitted worldwide due to fossil fuel combustion
and cement production. Express this mass of CO2 in grams without exponential notation, using an appropriate metric prefix

Answers

The mass of CO₂ in grams without exponential notation and with the appropriate metric prefix is 31.6 Eg.  

First, let's calculate the amount of mass in grams of 31.6 billion metric tons.

Knowing that 1 metric ton is equal to 1000 kg, 31.6 billion metric tons is:

[tex]m = \frac{1000 kg}{1 \: metric \: ton}*\frac{1000 g}{1 kg}*31.6 \cdot 10^{12} \: metric \: ton = 3.16 \cdot 10^{19} g[/tex]              

The metric prefix that is close to the above result is exa (E), which is equal to 10¹⁸.

Therefore, the mass of CO₂ in grams without exponential notation and with the appropriate metric prefix is 31.6 Eg (exa-gram).  

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draw a diagram to show what happened to the particle, when a liquid cools to a solid? ​

Answers

Hope it helps you

And do follow if you appreciate it

Which of the following is an example of a change from gravitational potential
energy to kinetic energy?

Answers

Answer:

The speed of a roller coaster increases as gravity pulls it downhill and is greatest at its lowest point. Viewed in terms of energy, the roller-coaster-Earth system's gravitational potential energy is converted to kinetic energy

Explanation:

a ball held in the air is the example of a change from gravitational potential energy to kinetic energy.

The mass of an atom of element x is equivalent to the total mass of 7 hydrogen atoms

Answers

hydrogen mass is 1, the atom with mass number 7 is Lithium

what is the density of a 5 mL sample of 1.95g of Gold

Answers

Answer:

density=mass/volume

=1.95/5 = 0.39 g(mL)-¹

convert 6.86 km into m​

Answers

Hi there!

1 km=1000m

so

6.86 km = 6.86×1000= 6860 m

have a nice day

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Consider the addition of NaCl to the ice-water mix in Part II. Which of the following statements is TRUE?

a. Salt lowers the freezing point of water by interfering with the intermolecular forces of the water molecules, allowing for more interactions between water molecules.
b. Salt lowers the freezing point of water by interfering with the intermolecular forces of the water molecules, allowing for less interactions between water molecules.
c. Salt raises the freezing point of water by interfering with the intermolecular forces of the water molecules, allowing for less interactions between water molecules
d. None of the above are correct.

Answers

b is correct

salt lowers the freezing point of water (colligative property) by lowering the interaction and intermolecular forces between water molecules

Salt lowers the freezing point of water by interfering with the intermolecular forces of the water molecules, allowing for less interactions between water molecules.

What is freezing point?

The Freezing point is the temperature of a liquid at which it changes its state from liquid to solid at atmospheric pressure.

Salt molecules block water molecules from packing together when temperature is lowered. It then prevents them from becoming ice. More water molecules leave the solid phase than the ones entering the solid phase. Freezing point depression occurs when the freezing point of the liquid is lowered by addition of solute.

Hence, option B is correct.

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Please help!!! Question 1 to 8

Answers

Answer:

1) C - 30

2) A - MgO

3) C - 3Cu + N2 + 3H2O

4) C - 100

Explanation:

Diagram 1 shows the species of carnivore animal. (tiger)

What is the use of canine teeth for the animal?

a. Tear food
b. grind food
c. cut food
d. chewing and crushing food​

Answers

Answer:

a no. because tearing the raw meat will not be easy without the use of the canine teeth

What is the safe way to dispose of an acidic solution

Answers

I'd say by Neutralization so as to make it Harmless.

Or

You Over dilute it with Water

Note: You pour the acid into water...Not water into acid as it may spill and burn your skin.

Answer: D

Explanation:

Which benzene derivative would be the least reactive in an electrophilic aromatic substitution reaction

Answers

benzene with electron withdrawing group as a substituent will be least reactive in an electrophilic aromatic substitution

example of electron withdrawing group are: NO2, carbonyls

illustrate the law of multiple proportions using the formation of SO2 and SO3 by sulphur and oxygen​

Answers

In SO2 and SO3, oxygen combines with sulphur in a fixed ratio.

The law of multiple proportion states that if two elements combine with each other to form more than one chemical compound, then the various masses of the elements which combine with a fixed mass of the other element are in simple multiple ratios.

To illustrate this law, sulphur forms two oxides, SO2 and SO3. The ratio of the oxygen that combines with a fixed mass of sulphur  in the two compounds is 2:3 in accordance to the law of multiple proportion.

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what happens when we mix stone in water observation ​

Answers

Answer:

hope it's help you dear

Explanation:

If one drops a stone into a pond, a very rapid, thin jet of water spouts upwards. ... A cavity forms behind the object during impact on the water surface. This cavity is subsequently compressed by hydrostatic pressure, which leads to the formation of the jet

Isotopes have
Question 3 options:

A)

a different number of neutrons in their nuclei.

B)

a different number of protons in their nuclei.

C)

a different number of electrons.

D)

different numbers of both protons and neutrons in their nuclei.

Answers

A. isotopes only hve different mass which is caused by additional/lesser neutron. protons and electrons number are fixed

Answer:

a different number of neutrons in their nuclei.

Explanation:

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