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Alenkasestr [34]
3 years ago
9

What determines what elements end up on the periodic table?

Chemistry
1 answer:
AfilCa [17]3 years ago
7 0
Their atomic number
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Pls I need help give away 11 points
Maru [420]

Answer:

The charge is +2

Explanation:

Protons are positive, electrons are negative. 10-8=2.

+2 :)

7 0
3 years ago
Calculate how many grams of o2(g) can be produced from heating 87.4 grams of kclo3(s).
Rufina [12.5K]
<span>34.2 grams Lookup the atomic weights of the involved elements Atomic weight potassium = 39.0983 Atomic weight Chlorine = 35.453 Atomic weight Oxygen = 15.999 Molar mass KClO3 = 39.0983 + 35.453 + 3 * 15.999 = 122.5483 g/mol Moles KClO3 = 87.4 g / 122.5483 g/mol = 0.713188188 mol The balanced equation for heating KClO3 is 2 KClO3 = 2 KCl + 3 O2 So 2 moles of KClO3 will break down into 3 moles of oxygen molecules. 0.713188188 mol / 2 * 3 = 1.069782282 mols So we're going to get 1.069782282 moles of oxygen molecules. Since each molecule has 2 atoms, the mass will be 1.069782282 * 2 * 15.999 = 34.23089345 grams Rounding the results to 3 significant figures gives 34.2 grams</span>
4 0
3 years ago
How many of the following are oxidation-reduction reactions? I. reaction of a metal with a nonmetal II. synthesis III. combustio
nadezda [96]

Answer : The oxidation-reduction reactions are:

I. reaction of a metal with a nonmetal

II. synthesis

III. combustion

Explanation :

Redox reaction or Oxidation-reduction reaction : It is defined as the reaction in which the oxidation and reduction reaction takes place simultaneously.

Oxidation reaction : It is defined as the reaction in which a substance looses its electrons. In this, oxidation state of an element increases. Or we can say that in oxidation, the loss of electrons takes place.

Reduction reaction : It is defined as the reaction in which a substance gains electrons. In this, oxidation state of an element decreases. Or we can say that in reduction, the gain of electrons takes place.

I. Reaction of a metal with a nonmetal :

When sodium react with chlorine gas then it react to give sodium chloride.

2Na+Cl_2\rightarrow 2NaCl

In this reaction, the oxidation state of sodium changes from (0) to (+1) and shows oxidation and the oxidation state of chlorine changes from (0) to (-1) and shows reduction. So, It is an oxidation-reduction reaction.

II. Synthesis reaction :

A chemical reaction where multiple substances or reactants combine to form a single product.

When hydrogen react with oxygen then it react to give water.

2H_2+O_2\rightarrow 2H_2O

In this reaction, the oxidation state of hydrogen changes from (0) to (+1) and shows oxidation and the oxidation state of oxygen changes from (0) to (-2) and shows reduction. So, It is an oxidation-reduction reaction.

III. Combustion reaction :

A chemical reaction in which a hydrocarbon reaction with the oxygen to give product as carbon dioxide and water.

When methane react with oxygen gas then it react to give carbon dioxide and water.

CH_4+2O_2\rightarrow CO_2+2H_2O

In this reaction, the carbon of methane gain oxygen and shows oxidation and the oxygen gas gain hydrogen and shows reduction. So, It is an oxidation-reduction reaction.

IV. Precipitation reaction :

It is defined as the reaction in which an insoluble salt formed when two aqueous solutions are combined.

The insoluble salt that settle down in the solution is known an precipitate.

It is a double displacement reaction. So, it is not an oxidation-reduction reaction.

V. Decomposition reaction :

A chemical reaction in which the the larger molecule decomposes to give two or more smaller molecules.

The oxidation state remains same on reactant and product side. So, it is not an oxidation-reduction reaction.

3 0
3 years ago
Which of the following is the best definition of a scientific theory? A predicted experimental outcome A mathematical model (an
Mkey [24]

Answer:

A well tested explanation of a natural phenomenon

Explanation:

A scientific theory is an explanation of a natural phenomenon which has been drawn from a well tested observation.

Theories are products of repeated scientific experiments. When a hypothesis otherwise known as a "scientific guess" survives a lot of scrutiny, we can elevate it to the status of a theory. Most theories starts off from simple observations. These observations can further spark series of experiments in such a field and a scientific guess proposed. Further testing and experimenting would now lead to a theory.

7 0
3 years ago
What is electron configuration of oxygen in its excited state​
timofeeve [1]

Answer:

1 {s}^{2} 2 {s}^{2} 2 {p}^{4}

OR

2 : 6

3 0
3 years ago
Read 2 more answers
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