CHEMISTRY HIGH SCHOOL

Please Help meHello guys,i really need your help for a few questions about the greek philosopher "Democritus"
1)revisions that were made to Democritus's model once further research was done.
2)one challenge that the scientist had to overcome.

please help me

Answers

Answer 1
Answer: Democritus was the first to propose the idea of the atom. He said the atom was just this tiny, solid sphere. However, he used no scientific evidence to support his claim, so a guy named John Dalton did some experimenting and basically backed up Democritus' claim with evidence. Then, a guy named J.J. Thompson came along and said the atom was not solid and that is consisted of tiny negatively charged particles(electrons) and he came up with the Plum Pudding model which is just a tiny sphere with a punch of random scattered dots in it. After that, Ernest Rutherford did experiments and found that the tiny sphere is made up of mostly empty space with a tiny, dense, positively charged sphere inside of it, and the negatively charged particles just randomly float around it. Neils Bohr then said that the electrons take specific, circular, evenly spaced paths. Then, finally, we come to the Quantum Mechanical Model which is the one accepted today. This model basically vetos Bohr's idea and has a nucleus inside of an electron cloud, which is where the electrons are found.

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Given the unbalanced ionic equation:3Mg + ____ Fe3+ ==> 3Mg2+ + ____ FeWhen this equation is balanced, both Fe3+ and Fe have a coefficient of(1) 1, because a total of 6 electrons is transferred(2) 2, because a total of 6 electrons is transferred(3) 1, because a total of 3 electrons is transferred(4) 2, because a total of 3 electrons is transferred
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Which of the following is a balanced chemical equation for the synthesis of NaBr from Na and Br2? A. 2Na + Br2 --> 2NaBr B. NaBr --> Na + Br2 C. 2NaBr --> 2Na + Br 2 D. 2Na + Br2 → NaBr

Answers

Answer:

A) 2Na + Br_(2) = 2NaBr

Explanation:

As the problem says that you should find the balanced chemical equation for the synthesis of NaBr from Na and Br_(2), the reactants are Na and Br_(2) and the product is NaBr, so it can be writen as:

Na + Br_(2) = NaBr

Then you shoud balance the equation, it means that you should have the same number of each element in each part of the equation, so if you put a number 2 for the NaBr and the Na, the equation will be balanced:

2Na + Br_(2) = 2NaBr
A. 2Na + Br2-->2NaBr.

Describe several uses for plastic and explain why plastic is a good choice for these properties

Answers

Plastics are used in almost all spheres of life for diverse purposes because of their beneficial properties. The uses of plastics include the following:

1. Plastics are used in the manufacturing of various items that we use in our homes such as television, phones, radio, vacuum cleaners, chairs, bowls plates, tables, etc.

2. Plastics are used in the food industry for packaging of foods.

3. Plastics are used in the transport industry for various purposes in the manufacture of cars, trains, aeroplanes, hydroplanes, ships, satellites, etc.

4. Plastics are also used in the medical and pharmaceutical industries for various purposes.

Manufacturers are able to use plastics for various purpose because of their properties, which include: resistance to corrosion, resistance to chemicals, low thermal conductivity, color variability, high strength to weight ratio, resistance to shock, durability, low toxicity, ready availability, cheap, etc.
Plastic is used in several in the worlds toys, bags and products. Its a good choice for these properties because plastic is a low cost and is very durable and flexible allowing it to ease the process of making these products.

A solution of methanol and water has a mole fraction of water of 0.312 and a total vapor pressure of 211 torr at 39.9 ∘C. The vapor pressures of pure methan ol and pure water at this temperature are 256 torr and 55.3 torr, respectively. ls the solution ideal? If not, what can you say about the relative strengths of the solute-solvent interactions compared to the solute-solute and solvent-solvent interactions?

Answers

Answer:

Weaker

Explanation:

The strategy here is to use Raoult´s law to calculate the theoretical vapor pressure for the concentrations given and compare it with the experimental value of 211 torr.

Raoult´s law tell us that for a binary solution

P total = partial pressure A + partial pressure B = Xa PºA + Xb PºB

where Xa and Xb are the mol fractions, and  PºA and PºB are the vapor pressures of pure A and pure B, respectively

For the solution in question we have

Ptotal = 0.312 x 55.3 torr + ( 1- 0.312 ) x 256 torr     ( XA + XB = 1 )

Ptotal = 193 torr

Since experimentally, the total vapor pressure is 211 and our theoretical value is smaller ( 193 torr ), we can conclude the interactions  solute-solvent are weaker compared to the solute-solute and solvent-solvent interactions.

In the chemical equation Zn + 2HCl ZnCl2 + H2, the reactants are A. zinc and hydrochloric acid.
B. zinc and hydrogen carbonate.
C. zinc chloride and hydrogen.
D. zinc chlorate and water.

Answers

In the chemical reaction: Zn + 2HCl -> ZnCl₂ + H₂, the reactants are zinc, Zn and hydrochloric acid, HCl (Option A)

How to determine the reactants in the reaction?

Chemical equations are representation of chemical reactions with symbols and formula of elements involved in the reaction.

Every chemical equation has two sides. These are:

  1. Reactants: They are located on the left hand side of the equation
  2. Products: They are located on the right hand side of the equation

With the above information, we can determine the reactants of the chemical equation. This is shown below:

  • Chemical reaction: Zn + 2HCl -> ZnCl₂ + H₂
  • Reactant =?

Reactants => They are located on the left hand side of the equation

=> Zn and HCl

Thus, the correct answer to the question is: zinc and hydrochloric acid (option A)

Learn more about reactants in reaction:

brainly.com/question/14321137

#SPJ6
The answer is A ( and the answer for the products is C )

Which of the following metal atoms would have the highest conductivity?

Answers

Conductivity is a way that an atom reacts. Therefore, when we say "highest" we mean the most reactive. Elements or atoms that are highly reactive are those that want to be stable. Therefore, the atoms that have 7 valence electrons would be highly reactive because they need 1 more electron to fill their outer energy shell to become stable. 

Answer:The atom with the largest radius and the most valence electrons.

Explanation:it just makes sense and it’s also right.

Salt water is classified as a1) compound because the proportion of its atoms is fixed
2) compound because the proportion of its atoms can vary
3) mixture because the proportion of its components is fixed
4) mixture because the proportion of its components can vary

Answers

Salt Water is classified as a:

4) mixture because the proportion of its components can vary.

Salt water is composed of salt and water.  Regardless of the amount of salt or water put together, these two still form salt water.

Answer:

4) mixture

Explanation:

The answer is 4) because salt water has 2 properties which are salt and water.  Never the less the amount of salt or water you keep adding the substance would always remain as salt water.
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