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Anna007 [38]
2 years ago
12

PLEASE HELP!!! Which of John Dalton's contributions are present in the modern atomic model and which were eventually disproven a

nd thus are not part of the modern model??? If you have any questions please don't ask in the answer box.
Chemistry
1 answer:
Yanka [14]2 years ago
5 0
1) All matter is made of atoms. Atoms are indivisible and indestructible.

2) All atoms of a given element are identical in mass and properties

3) Compounds are formed by a combination of two or more different kinds of atoms.

4) A chemical reaction is a rearrangement of atoms.

1 and 2 were proved wrong.
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What is the similarity between simple diffusion and facilitated diffusion?
MakcuM [25]

they are both types of passive transport which means they require no energy. They both work with the concentration gradient which means they go from a high concentration area to a low concentration area. The differences are simple diffusion just goes though the membrane of a cell while facilitated diffusion uses a protein channel

Simple diffusion: it is the process where molecules move from a area of high concentration to an are of lower concentration. There is no energy needed in simple diffusion. For example when sodium is highly concentration in a cell, it moves outside of the cell where sodium is less concentration. it takes no energy as simple diffusion is random and molecules move according to their concentration.

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4 0
3 years ago
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Question 2
natulia [17]

Explanation:

de Broglie wavelength= h/mv

v=h/m x de Broglie wavelength

v= (6.626× 10^-34)/ (2347× 1.27 × 10^-38)

v= 22.229 m/s(according to Google scientific calculator)

am sorry I don't hv a calculator at hand

3 0
3 years ago
Calculate the energy required to ionize a hydrogen atom to an excited state where the electron is initially in the n = 5 energy
SVETLANKA909090 [29]

. The energy of shells in a hydrogen atom is calculated by the formula E = -Eo/n^2 where n is any integer, and Eo = 2.179X10^-18 J. So, the energy of a ground state electron in hydrogen is:

E = -2.179X10^-18 J / 1^2 = -2.179X10^-21 kJ

Consequently, to ionize this electron would require the input of 2.179X10^-21 kJ


2. The wavelength of a photon with this energy would be:

Energy = hc/wavelength

wavelength = hc/energy

wavelength = 6.626X10^-34 Js (2.998X10^8 m/s) / 2.179X10^-18 J = 9.116X10^-8 m

Converting to nanometers gives: 91.16 nm


3. Repeat the calculation in 1, but using n=5.


4. Repeat the calculation in 2 using the energy calculated in 3.

7 0
3 years ago
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PLEASE HELP ME WITH A COUPLE OF QUESTIONS!!! Thank You :)
Brrunno [24]
Hey there!

1. A chemical reaction is, B).<span> Any time different substances combine to form a new substance, or when a substance breaks up into different substances

2.</span> Balancing chemical equations is called, C). <span>Equivalentry

3.</span><span> Sulfuric acid is made of two hydrogen atoms (H), one sulfur atom (5), and four oxygen atoms (0). What is its formula? C). </span><span>H2S04


Hope this helps!


-Much love, Makayla</span>
5 0
3 years ago
Why does the chemical reaction seen here obey the law of conservation of matter?
ss7ja [257]

Why does the chemical reaction seen here obey the law of conservation of matter?

<u><em>Answer:</em></u>

  • Because there are the same number of atoms of each element shown on both sides

<u><em>Explanation</em></u>

  • As in chemical reactions, atoms bonds are break and new bonds are formed. As new substance are formed but overall they have same elements, no new elements come from outside or go to outside. In other words , rearrangement of atoms take place but number of atoms remained same.

                            NaOH + HCl -----> NaCl + H2O

  • As in above reaction there are the same number of atoms of each element shown on both sides .
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3 years ago
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