Which statement about exothermic reactions is TRUE?
A.In an exothermic reaction, energy is absorbed, bonds are broken, and the temperature decreases.
B. In an exothermic reaction, energy is released, bonds are formed, and the temperature increases.

Answer:

Around 400 B.C.E., the Greek philosopher Democritus introduced the idea of the atom as the basic building block matter.

Explanation:

Hope this helps.

Taking into account the definition of ionization energy and electronegativity, you can say that the significance of the similarity of these trends  is that while electrons are more attracted to the nucleus (electronegativity), more energy is needed to extract an electron from a neutral atom (ionization energy).

Electrons are held in atoms by their attraction to the nucleus, which means that energy is needed to remove an electron from the atom.

Ionization energy, also called ionization potential, is the necessary energy that must be supplied to a neutral, gaseous, ground-state atom to remove an electron from an atom. When an electron is removed from a neutral atom, a cation with a charge equal to +1 is formed.

The further away the electron is from the nucleus, the easier it is to remove it, that is, the less energy is needed.

In a group the atoms have the same electronic structure in the outermost shell. But when going down in the same group, the electrons find themselves in shells that are farther and farther away from the nucleus, being less and less attracted. The size of the atom increases as the number of electronic shells increases, increasing the atomic radius when descending in a group. But the electrons are farther from the nucleus, and the easier it will be to expel them. That is, its extraction from the atom is facilitated. So the ionization energy decreases when descending in a group. In other words, ionization energy is a function of atomic radius; the larger the radius, the less energy is required to remove the electron from the outermost orbital.

By increasing the atomic number of the elements of the same period, the nuclear attraction on the outermost electron increases, since the atomic radius decreases and the effective nuclear charge on it increases.

For this reason, in a period, as the atomic number increases, the ionization energy becomes greater.

The electronegativity of an element is defined as the relative ability of an atom to attract electrons from another atom to chemically bond and form a compound.

In other words, electronegativity is a measure of the attractive force that one atom exerts on the electrons of another when a chemical bond forms.

In the groups, the electronegativity decreases from top to bottom because the valence shell moves away from the nucleus and with this the attraction that the nucleus exerts on the valence electrons decreases.

In the periods, the electronegativity increases from left to right, because the number of electrons in the valence shell increases, so the attraction of other electrons increases to complete the valence shell and reach a stable state.

The significance of the similarity of these trends  is that while electrons are more attracted to the nucleus (electronegativity), more energy is needed to extract an electron from a neutral atom (ionization energy).

Then, electronegativity is related to ionization energy in the following way: an atom with a high ionization potential has a high electronegativity. On the contrary, atoms with low ionization potential have small electronegativity.

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Answer:

Anything not on the periodic table is an element non example! ... So, for a substance to be an element, all of its atoms must have the same number of protons. Examples of elements include hydrogen, lithium, nickel, and radium.

Explanation:

Non-examples of an atom refer to entities that are not considered atoms.

Molecules consist of two or more atoms chemically bonded together. They are not considered individual atoms because they contain multiple atoms connected by chemical bonds.

Ions are electrically charged particles formed when atoms gain or lose electrons. They can be positively charged (cations) or negatively charged (anions).

Subatomic particles are the constituents of atoms. They include protons, neutrons, and electrons.

Compounds are substances composed of two or more different elements chemically combined.

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Answer:

I think it's B or A. Though I believe it is more so B. I think I'm right though.

Explanation:

Answer:

I believe the answer is II and III

Explanation:

I'm not sure if III is right cause I cannot read the last word but I think it's OK.

Hope this helped :)

Explanation:

Atomic;

Numb...

SymbolN

ame

Atomic Mass...1HHydrogen1.007972HeHelium4.002603LiLithium6.941

The mass of ammonia that would be produced is 312.5 g

First, we will write a balanced chemical equation for the reaction

The balanced chemical equation for the reaction is

3H₂(g) + N₂(g) → 2NH₃(g)

This means

3 moles of hydrogen gas reacts with 1 mole of nitrogen gas to produce 2 moles of ammonia.

First, we will determine the number of moles of each reactant present

For Hydrogen (H₂)

Mass = 83.6 g

Molar mass = 2.016 g/mol

Using the formula

[tex]Number\ of\ moles = \frac{Mass}{Molar\ mass}[/tex]

Number of moles of H₂ present = [tex]\frac{83.6}{2.016}[/tex]

∴ Number of moles of H₂ present = 41.468254 moles

For Nitrogen (N₂)

Mass = 257 grams

Molar mass = 28.0134 g/mol

∴ Number of moles of N₂ present = [tex]\frac{257}{28.0134}[/tex]

Number of moles of N₂ present = 9.174181 moles

Since,

3 moles of hydrogen gas reacts with 1 mole of nitrogen gas to produce 2 moles of ammonia

Then,

27.522543 moles of hydrogen gas will react with the 9.174181 moles of nitrogen gas to produce 18.348362 moles of ammonia

∴ 18.348362 moles of ammonia will be produced during the reaction

Now, for the mass of ammonia that would be produced

From the formula

Mass = Number of moles × Molar mass

Molar mass of ammonia = 17.031 g/mol

Mass of ammonia that would be produced = 18.348362 × 17.031

Mass of ammonia that would be produced = 312.49095 g

Mass of ammonia that would be produced ≅ 312.5 g

Hence, the mass of ammonia that would be produced is 312.5 g

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Explanation:

Hydrogen is a very special element of the periodic table and doesn't belong to any family. While hydrogen sits in Group I, it is NOT an alkali metal.

Answer:

9

Explanation:

i think i dont know

maybe someone tell me if I'm wrong

Answer:A, Both reactivity and electronegativity decrease down a group.

Explanation: As you go down the periodic table they both will decrease

Answer:

When 6.38 moles of O2 and 9.15 moles of Al react, the ratio of aluminum to oxygen is 9.15/6.38 = 1.434. This shows that all of the oxygen is consumed before the aluminum and when the reaction ends the reactant aluminum is left. The number of moles of Al2O3 formed is approximately 4.25 moles.

___

Regarding the bonds in FesO₄, Fe and S have an ionic bond, while S and O have covalent bonds.

Elements form bonds to increase their stability. The main types of bonds are:

Regarding the bonds in FesO₄:

Regarding the bonds in FesO₄, Fe and S have an ionic bond, while S and O have covalent bonds.

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b) unsaturated

Hope this helped you- have a good day bro cya)

Answer:

0.690 liters is the volume of hydrogen gas produced if 2.00 grams of zinc is used with an excess of hydrochloric acid.

Explanation:

Zn(s)+2HCl(aq)\rightarrow ZnCl_2(aq)+H_2(g)Zn(s)+2HCl(aq)→ZnCl2(aq)+H2(g)

Mole so zinc = \frac{2.00}{65 g/mol}=0.03077 mol65g/mol2.00=0.03077mol

According to reaction, 1 mole of zinc gives 1 mole of hydrogen gas.

Then 0.03077  mole of zinc will give :

\frac{1}{1}\times 0.03077 mol=0.03077 mol11×0.03077mol=0.03077mol of hydrogen gas

Pressure of hydrogen gas ,P= 1 atm

Temperature  of of hydrogen gas ,T= 273.15 K

Volume of hydrogen gas = V = ?

Moles of hydrogen gas = 0.03077 mol

PV = nRT (Ideal gas equation )

V=\frac{nRT}{P}=\frac{0.03077 mol\times 0.0821 atm L/mol K\times 273.15 K}{1 atm}V=PnRT=1atm0.03077mol×0.0821atmL/molK×273.15K

V = 0.690 L

Answer:

It is reactive because it has to gain an electron to have a full outermost energy level.

Explanation:

Answer:

A

Explanation:

Explanation:

Atoms are at their most stable when their outermost energy level is either empty of electrons or filled with electrons. Sodium atoms have 11 electrons. Two of these are in the lowest energy level, eight are in the second energy level and then one electron is in the third energy level.

Any atom is most stable when it’s outermost energy level contains eight electrons.

An atom is defined as the smallest unit of matter which forms an element. Every form of matter whether solid,liquid , gas consists of atoms . Each atom has a nucleus which is composed of protons and neutrons and shells in which the electrons revolve.

The protons are positively charged and neutrons are neutral and hence the nucleus is positively charged. The electrons which revolve around the nucleus are negatively charged and hence the atom as a whole is neutral and stable due to presence of oppositely charged particles.

Atoms of the same element are similar as they have number of sub- atomic particles which on combination do not alter the chemical properties of the substances.

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Answer:

see explanation

Explanation:

Question

A(n) ACID is a compound that dissolves in water to produce hydrogen ions in solution. A(n) _BASE__ URhydroxide ions. Acids have a SOUR___ taste and bases have a BITTER____ taste. Both acids and bases conduct _ELECTRICITY___ and are _REACTIVE___. A pH of7 ____ is neutral. A pH of 6 is _ACIDIC__ and a pH of 14 is a BASIC__

Answer:

A push or pull is referred to as a force. Forces can cause objects to move, slow, stop, or change the direction in which they travel. The force of gravity, for example, pulls all objects toward the Earth's center. Every time two things interact, a force is exerted on each of them. When this happens, the two items no longer feel the force after the interaction ends.

Explanation:

Force is that external physical cause which changes or tends to change:

hope this helps you.

Answer:

The choice that we had decided on doing today factors our future because whatever choice we decide on doing in the present day can impact how our life will play out in the future. ... After all, it is your life, so whatever you chose to do, you have the power to decide and create what you think would be best for you

Explanation:

Answer:

That would be the necleus! I hope this helps you! :)

Explanation:

The next step in the scientific method is to analyze the data. Data analysis is the process of interpreting the meaning of the data we have collected, organized, and displayed in the form of a table or graph.

Answer: the ground

Explanation:

Answer:

La fuerza gravitacional entre el planeta y el Sol aumenta.

Explanation:

Answer:

Br6Si2

Explanation:

The chemical formula for disilicon hexabromide is Si₂Br₆.

The chemical formula of a compound is a symbolic representation of its chemical composition.

Chemical formulae gives information about the elements that constitute the molecules of a compound and also about the ratio in which the atoms of these elements combine to form such molecules.

Every constituent component in a chemical formula is identified with its chemical symbol, along with the relative number of atoms that make up each element.

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The physical quantity that is not used when determining the stoichiometry in this experiment is temperature.

Stoichiometry offers a way in which we can calculate the amount of reactants and products using mass - mole relationship. The mass of reactants, number of moles of reactant, mass of product and mass of precipitate can all be used to determine the stoichiometry.

However, the temperature of a reaction is not used to determine the stoichiometry of the reaction.

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Which physical quantity is NOT used when determining the stoichiometry in this experiment?

Answer:

Oxygen Reacts with Iron to Form Rust is the Correct Answer

Answer:

I don't know

Explanation:

pls I need a little bit answer

Answer: Methane is a gas at standard conditions.

Explanation: However, at low temperature and/or high pressures the gas becomes a liquid or a solid.

Answer: yes

Explanation: