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What is the overall charge of the nucleus of an atom, and why?

An atom comprises a tiny nucleus surrounded by moving electrons. And nucleus is basically a collection of neutrons and protons where

  • Neutrons are electrically neutral
  • And Protons are positively charged

 

So, what is the overall charge of the nucleus of an atom?

A nucleus is consists of the neutrons and protons where

  • Neutrons have a neutral charge
  • And Protons have a positive charge

A neutral charge won’t cancel out the positive charge that indicates that the overall charge of a nucleus is positive.

 

And why is the overall charge of a nucleus Positive?

The neutrons present in the nucleus have a neutral charge, whereas the protons in the nucleus have a positive charge. As neutral won’t cancel out the positive charge, so the overall charge of the nucleus is positive.

 

What determines the positive charge of the nucleus?

The number of protons present in the nucleus determines the positive charge of the nucleus.

As the protons are positively charged, and a nucleus comprises protons and neutrons, so the protons present in the nucleus determine the positive charge.

Even though the nucleus contains neutrons also, they do not impact the charge as they have no charge, and therefore they do not contribute to the nucleus charge.

 

Bottom Line!

A combination of neutral particles and positively charged particles definitely forms a positively charged particle only.

Therefore, a nucleus has an overall positive charge.

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Explain what occurs when an acid reacts with an alkali in terms of ions and molecules. Also, show the equation.

When an acid reacts with an alkali, a chemical reaction happens and the formation of a new substance takes place.

Let us get acquainted with everything you need to know about the query.

  • What happens when you react acid with Alkali?

Whenever you add acid with Alkali, a chemical reaction takes place, and a new substance is formed.

If you mix the exact amounts of acid with Alkali, you will end up with a neutral solution which is also known as a neutralization reaction.

  • What exactly is it called when an acid reacts with Alkali?

An acid reaction with Alkali or, say, an acid-alkali neutralization refers to a reaction between the hydroxide and hydrogen ions forming water.

  • Whenever an acid and Alkali are mixed, what sort of reaction takes place?

Whenever the acid and Alkali are mixed, a neutralization reaction takes place, forming salt and water.

A neutralization reaction is always

Acid + Alkali ——> Salt + Water

Equation of acid reacting with Alkali

H+ + OH- —> H20

However, here the question is about ions, and there is no salt. So, the acids are H+ ions that give them the desired acidic properties, and alkalis are the OH- ions. And together, they react to form water.

Essential to Remember!

  • Alkalis in the solution are the sources of Hydroxide ions represented by OH-
  • And Acids in the solution are the sources of Hydrogen ions represented by H+.

And so the reaction is represented as

H+ (aq) + OH- (aq) → H2O (l)

 

Bottom Line!

When it comes to checking the reaction of an acid with alkalis in terms of ions and molecules, the Hydrogen ions from the acid react with the hydroxide ions from alkalis to form water.

And the reaction is represented as

H+ (aq) + OH- (aq) → H2O (l)

 

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Describe the differences between the three types of bonding

The three types of bondings are namely

  • Ionic Bonding
  • Covalent bonding
  • Metallic Bonding

Let us get acquainted with all the essential information concerning all three types of bondings.

What is ionic bonding?

Ionic bonding is the one that takes place between metals and non-metal atoms.

This type of bonding generally involves the electrons transfer from metal to non-metals developing a negatively charged non-metal ion and a positively charged metal ion.

For instance, Na+ and Cl- making NaCl.

These are more like the blood donations where a metal atom gives its electrons to a non-metal atom.

Since the electrons are negatively charged, that means the metals become more positive while the non-metals become more negative. Just like south and north on a magnet!

 

What is covalent bonding?

Covalent bonding takes place between the non-metal atoms only. Here instead of the electrons transfer taking place in the ionic bonding, this type of bonding includes the electrons sharing between the non-metal atoms.

For instance, H+ and OH- make H2O.

Covalent bonds are the ones where two atoms share their electrons. The orbitals that electrons sit in overlie between one atom and the next. This satisfies both the atoms and makes them stable.

Some of the two non-metal atoms that cannot even easily move away from each other are more like the blood brothers.

 

What is metallic bonding?

Metallic bonding is the one that is different from other types of bonding as it occurs between metal atoms only.

Here the metal atoms are arranged in a regular pattern in which the electrons in the outermost shell are delocalized and form solid metallic bonds.

For instance, Metals like iron, zinc, etc.

Here the extra electrons present in the metal atoms are dropped, making the metal a positive ion.

And the extra electrons become an electrons sea that is negative, so the positive metals stick to the negative electrons while forming a large metallic lattice structure.

 

Understanding the differences between the three types of bonding

Parameters Ionic Bond Covalent Bond Metallic Bond
Occurrence It occurs during the electrons transfer It takes place when two electrons share their valence electrons. It takes place during the attraction of metal atoms/ cations and delocalized electrons
Binding Energy Here the binding energy is higher than the metallic bond. Here the binding energy is higher than the metallic bond Here the binding energy is lower than the ionic and covalent bond
Bonds Non Directional bonds Directional bonds Non-directional bonds
Conductivity It has Low Conductivity It has a Very Low Conductivity It has a higher electrical conductivity/
Molding property It is unmoldable It is unmoldable It is moldable
States It is present in only one state that is the solid state It is present in all three states including the solids, liquids, and gases It is present in only one state that is the solid state
Ductile property It is non-ductile It is non-ductile It is ductile
Melting Point It has a higher melting point It has a lower melting point It has a higher melting point
Boiling point It has a higher boiling point It has a lower boiling point It has a higher boiling point

 

Bottom Line!

The major differences between all three bonds can be summed up like

  • Ionic bonds are formed due to the electron transforming from one atom to another.
  • The electron sharing between two atoms forms covalent bonds.
  • Metallic bonds are formed between the metal atoms and valence electrons.

 

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Describe why diamond is hard and Graphite is soft?

Even though Graphite and diamond are made of carbon, the diamond is hard, whereas the Graphite is soft.

This is due to the strong covalent bond among its atoms forming a regular tetrahedron that is difficult to break.

On the contrary, the Graphite comprises of a flat hexagonal ring forming the carbon atoms layers. The several layers of carbon atoms are so far away from each other that covalent bond formation cannot even exist.

These carbon atom layers are held together by the weak van der Waals forces, allowing them to slide over each other.

And because of this layered structure of carbon atoms, Graphite is stronger than diamond.

Take a rotating graphic of graphite molecules and a diamond structure and try this to understand the reason.

 

  • For Graphite

Rotate the graphite molecule. As the Graphite is layered, and there are strong covalent bonds between the carbon atoms present in each layer, only weak forces exist between layers. This permits the carbon layers to slide over each other.

  • For Diamond

Rotate the structure of the diamond, and do not forget that each diamond atom is at the same distance from each of its neighbouring carbon atoms.

There exists a rigid bonds network within the diamond crystal. And in this rigid network, the atoms cannot even move, which is why diamonds are hard.

Bottom Line!

Diamond has a 3-dimensional strong covalent bonds network, and it is very complicated to break the extended covalent bonding. And that is why the diamond is considered the hardest substance.

On the contrary, Graphite has layered structures that are held together by weak Vander Was forces. Therefore, Graphite cleaves easily between these layers, which is why they are soft and slippery.

 

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Balance the following equation: C3H8 + O2 —-> CO2 + H2O.

C3H8 + O2 ——-> CO2 + H2O

Balancing the equation

Comparing the number of reactants atoms with the number of products atoms.

First of all, list the number of each atom for the product and reactant, both sides of the equation.

Here in this example, listing the number of reactants and products can be written as

 

On the reactants side                                                On the product side

Carbon: 3                                                                                    Carbon: 1

Hydrogen: 8                                                                             Hydrogen: 2

Oxygen: 2                                                                                   Oxygen: 3

 

Writing the resultant equation

Now, after this, the first step to balance the number of carbon atoms is by multiplying the CO2 on the product side by 3. Therefore, the new equation will be then written as

C3H8 +O2 ——–> 3CO2 + H2O

As the carbon atoms are now balanced on each side, we will move further to balance the number of Hydrogen atoms.

The Hydrogen atoms at the reactant side are eight, whereas on the product side are two only, so multiplying the hydrogen on the product side will balance the number of the hydrogen atom. It makes sense, right?

Let us see multiplying four on the product side will make what sort of difference. Writing the resultant equation,

C3H8 + O2 —–> 3CO2 + 4H2O

Now we have eight hydrogen atoms on each side, as we are left with Oxygen atoms only to balance; let us see how we can attain that.

As there are 10 Oxygen atoms on the product side and only two on the reactants side. So, we need to balance that as well, and therefore, multiplying the O2 atoms with five will make 10 Oxygen atoms overall on the reactant side. Let us move further with the balancing of the equation.

Multiplying 5 with O2 on reactant side and writing the resultant equation

C3H8 + 5O2 ——–> 3CO2 + 4H2O

So, according to us, this is our balanced equation! Let us compare the number of atoms on each side.

 

On the Reactant side                                                 On the Product side 

Carbon: 3                                                                                    Carbon: 3

Hydrogen: 8                                                                             Hydrogen: 8

Oxygen: 10                                                                               Oxygen: 10

As the number of atoms on the products and reactant sides is equal, we can say that the equation is balanced.

 

Bottom Line!

C3H8 + 5O2 ——–> 3CO2 + 4H2O is the final balanced equation of the given equation.

Don’t forget to try the same method to balance your other equations.

 

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How do I know if an enthalpy change should be positive or negative?

An enthalpy change refers to the measure of heat absorbed or evolved. Let us get acquainted with everything you need to know about the Enthalpy change.

To better understand the energy change happening during a reaction, you need to understand the two parts of the universe, namely the surroundings and the system.

Surrounding refers to everything in the universe that is generally not a part of a system. The system relates to a matter’s specific position in a particular space studied during an observation or experiment.

Suppose a system loses a specific amount of energy. In that case, the same amount of energy is generally gained by the surroundings, whereas if a system gains a particular amount of energy, the same energy is supplied to by the surroundings.

  • A physical change or a chemical reaction is endothermic if the system from the surroundings absorbs the heat.

A physical change or a chemical reaction is endothermic if the system from the surroundings absorbs the heat

  • A physical change or chemical reaction is exothermic if the heat is liberated by the system into the surroundings.

A physical change or chemical reaction is exothermic if the heat is liberated by the system into the surroundings

What is Enthalpy?

Enthalpy refers to the heat changes in chemical reactions that are often measured in the laboratory under several conditions where the reacting system is open to the atmosphere. It’s a case where the system is at constant pressure.

So, we can say that the Enthalpy represented by H is the heat content of the system at a constant pressure. The changes in Enthalpy of a chemical system are routinely measured as the reactants are converted into products.

The heat released or absorbed by a reaction at constant pressure is similar to the enthalpy changes. It is given by the symbol ΔH.

 

Enthalpy Change

The enthalpy change of a reaction refers to the measure of differences in the Enthalpy of products and reactants. A system’s Enthalpy is generally identified by the energies required to break the chemical bonds and form chemical bonds.

 

A Thermochemical Equation

A thermochemical equation includes the enthalpy change of a reaction.

 

How do I know if the enthalpy change should be negative or positive?

A negative enthalpy change represents an exothermic reaction in which the energy is liberated from the reaction. In contrast, a positive enthalpy change represents an endothermic reaction in which the energy is taken in from the surroundings.

While deciding whether the change should be endothermic or exothermic and calculating the enthalpy change, you need to work on how many bonds are broken and how many bonds are formed.

The bond-breaking procedure requires energy, whereas the formation of the bond releases energy.

This applies to more than just the covalent bonds where attraction forces between the molecules are formed, which also applies to the energy release and vice versa.

In order to work out with the enthalpy change, we just add up the energies lost and gained in the reaction.

For instance, when working on the enthalpy formation of NaCl, when chlorine and sodium ions come together to generate NaCl.

NaCl is the one component of the overall reactions often known as lattice energy that we add up with several other components to identify the overall Enthalpy of formation.

 

So, should lattice enthalpy be negative and positive?

Bringing together the two oppositely charged ions, generating an ionic bond will liberate energy. It is an exothermic change where the lattice enthalpy must be negative.

 

When does the Enthalpy change positive or negative?

The enthalpy change ΔH is negative or positive is determined by

  • ΔH is negative for the exothermic reactions that evolve heat to the surroundings.
  • ΔH is positive for the endothermic reaction that absorbs heat from the surroundings.

 

Bottom Line!

The enthalpy change is negative or positive that is determined by the type of reaction. The Enthalpy is negative for exothermic reactions but is positive for endothermic reactions.

 

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