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frozen [14]
2 years ago
13

Which of these was not proposed by john dalton in 1805?

Chemistry
1 answer:
wel2 years ago
3 0

Answer:

Atoms are made of protons, neutrons and electrons.

Explanation:

The Dalton's atomic theory was an early attempt at describing the properties of atoms. It stipulated that atoms were the smallest indivisible particle of a substance. Chemical reactions occur as a result of a combination or separation of atoms. Atoms of the same element are exactly alike and differ from atoms of other elements. Atoms can neither be created nor destroyed.

As time went on, modern scientific evidence began to modify the original postulates of the Dalton's atomic theory. It was not postulated in 1805 that atoms were composed of subatomic particles; electrons, neutrons and protons. Dalton's theory held the atom to be 'indivisible'. However in 1897, JJ Thompson discovered the electron. Subsequently, the proton and neutrons were discovered. This shows that the atom in itself consisted of even smaller particles.

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Which of the following species contains manganese with the highest oxidation number?
ioda

In NaMnO₄, Mn has the highest oxidation number.

The question is incomplete, the complete question is;

Which of the following species contains manganese with the highest oxidation number?

A) Mn

B) MnF₂

C) Mn₃(PO₄)₂

D) MnCl₄

E) NaMnO₄

In order to ascertain the specie that contains manganese with the highest oxidation number, we must calculate the oxidation number of manganese in each of the species one after the other.

1) For Mn, the oxidation number of Mn is zero because the atom is uncombined.

2) For MnF₂;

Mn has an oxidation number of +2

3) For Mn₃(PO₄)₂

Mn has an oxidation number of +2

4) For MnCl₄

Mn has an oxidation number of +4

5) For NaMnO₄

Mn has an oxidation number of +7

Hence in NaMnO₄, Mn has the highest oxidation number.

Learn more: brainly.com/question/10079361

7 0
2 years ago
As part of an investigation, students combined substances in a beaker to observe chemical reactions. They performed two procedur
asambeis [7]

Answer:

D.

Explanation:

8 0
1 year ago
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Under standard conditions, a given reaction is endergonic (i.e., ΔG >0). Which of the following can render this reaction favo
sleet_krkn [62]

Answer:

Maintaining a high starting-material concentration can render this reaction favorable.

Explanation:

A reaction is <em>favorable</em> when <em>ΔG < 0</em> (<em>exergonic</em>). ΔG depends on the temperature and on the reaction of reactants and products as established in the following expression:

ΔG = ΔG° + R.T.lnQ

where,

ΔG° is the standard Gibbs free energy

R is the ideal gas constant

T is the absolute temperature

Q is the reaction quotient

To make ΔG < 0 when ΔG° > 0 we need to make the term R.T.lnQ < 0. Since T is always positive we need lnQ to be negative, what happens when Q < 1. Q < 1 implies the concentration of reactants being greater than the concentration of products, that is, maintaining a high starting-material concentration will make Q < 1.

5 0
2 years ago
In 200 g of a concentrated solution of 70.4 wt% nitric acid (r = 1.41 g/mL, FW(HNO3) = 63.01 g/mol), how many grams of water are
mars1129 [50]

Answer:

59.2 grams

Explanation:

We are given that 70.4% of the weight of the total 200 g of the concentration is made up of nitric acid, the remaining information is not required to solve the problem. Since water and nitric acid are the only components of the solution, the total weight of water is given by:

W = 200*(1-0.704)\\W=59.2\ g

There are 59.2 grams of water in this solution.

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2 years ago
How long would it take for 1.50 mol of water at 100.0 ∘c to be converted completely into steam if heat were added at a constant
Aleksandr-060686 [28]
To determine the time it takes to completely vaporize the given amount of water, we first determine the total heat that is being absorbed from the process. To do this, we need information on the latent heat of vaporization of water. This heat is being absorbed by the process of phase change without any change in the temperature of the system. For water, it is equal to 40.8 kJ / mol.

Total heat = 40.8 kJ / mol ( 1.50 mol ) = 61.2 kJ of heat is to be absorbed

Given the constant rate of 19.0 J/s supply of energy to the system, we determine the time as follows:

Time = 61.2 kJ ( 1000 J / 1 kJ ) / 19.0 J/s = 3221.05 s
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2 years ago
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