Elements and Compounds

It depends on the type of plastic and the type/strength of the acid.

Many plastics such as polyethylene (PE) and polypropylene (PP) are resistant to many common acids.

Some plastics can react, weaken, dissolve, crack, or degrade when exposed to strong acids or certain chemical conditions.

for more://nsda.gov.bd/pages/files/6922db73933eb65569e0a326

Sunscreen is a **mixture**, not a pure substance. It contains different ingredients combined together to protect the skin from UV rays and improve the texture and performance of the product.

Common Ingredients in Sunscreen

• UV filters (like zinc oxide or avobenzone)

• Moisturizers

• Oils or silicones

• Preservatives

• Fragrances or soothing ingredients

• Vitamins and antioxidants

Because sunscreen is made from multiple substances mixed together, it is classified as a mixture.

the equation is correct but some time scientist say there will be byproduct of glycerin is also obtained

In simple terms it is an hydrogen atom , consisting of one proton and one electron. The electron having been ionised off, to leave a 'charged proton' (symbolised as 'H^(+) '.)

However, in aqueous solutions, this 'loose' proton attached itself to the 'lone pair' on a water molecule, to form the ion ' H3O^(+) '.

Having a sexual fantasy about a family member can be unsettling and may evoke feelings of guilt or confusion. These fantasies can arise from a variety of psychological factors, including a complex mix of emotions and desires. It's important to recognize that fantasies do not necessarily reflect one's real-life feelings or intentions. If these thoughts cause distress, it might be helpful to speak with a mental health professional for guidance.

Phosphorus is NOT in Group '3' . It is Group '5' , with nitrogen.

However, it is in Period '3' (Third Row). of the Periodic Table.

Neon(Ne) is an INERT /NOBLE gas. It does not react with anything.

It exists as monatomic atoms.

Its atomic structure is ; -

Protons. 10

Electrons ; 10

Neutrons ; 10 ( commonest isotope).

Its atomic No, is '10'.

Its Atomic Mass is ; 20. ( 10 protons + 10 neutrons = 20 nucleons).

Argon(Ar) is an INERT /NOBLE gas. It does not react with anything.

It exists as monatomic atoms.

Both gases are found in the Periodic Table, in Group(18)/Noble Gases.

Its atomic structure is ; -

Protons. 18

Electrons ; 18

Neutrons ; 22 ( commonest isotope).

Its atomic No, is '18'.

Its Atomic Mass is ; 39.9. ( 18 protons + 22 neutrons = 40( ~39.9 nucleons).

Hydrogen is the only combustible element, other elements, need an interaction with "something else" other than its self to be combustible.

Therefore Hydrogen is the only "fuel". Fuel such as gasoline have bonds to Hydrogen that bulk it up, slow it down, and generally make Hydrogen dense.

Solid CO2 is known as 'Dry Ice'.

Carbon dioxide is a COMPOUND, composed of two elements viz. Carbon and oxygen.

The composition of this compound is

1 x carbon

2 x oxygen

Hence its formula ' CO2 '.

Any two or more different atoms combined together form a COMPOUND.

e.g. Water ( H2O ) is a compound

Methane ( CH4 ) is a compound

Ammonia ( NH3 ) is a compound.

New elements that are synthesised in a lab. are usually given a name of a scientist , or the place where they are first synthesised.

Have a look in the Periodic Table, at the Trans-Uranic elements. .

e.g. Californium ; first synthesised in California (USA) or 'Fermium' after Enrico Fermi , an Italian scientist. et.se

NB Most pre-trans-uranic elements occur naturally.

The name of the substance says it all. viz. Calcium and Bromine.

There are NO other elements present.

CaBr2 .

That is :-

1 x Calcium (Ca)

2 x Bromine(Br) [ as the bromide anion (Br^(-)) ] .

Yes!!!!

MgO (Magnesium oxide ) is a base, because it is a Group 2 metallic oxide.

An Alkali is a soluble base.

So if MgO is dissolved in water it forms the alkali magnesium hydroxide.

MgO(s) + H2O(l) = Mg(OH)2(aq)

NB Note the use of brackets in Mg(OH)2. This indicates that there are two hydroxide anions in the molecule. Writing as MgOH2 (No brackets) is INCORRECT, because it only indicates 1 x oxygen present , when there are actually 2 x oxygens in the molecule.

MgO + 2HCl = MgCl2 + H2O

The products are magnesium chloride and water.

When hydrochloric acid and magnesium carbonate react, they produce magnesium chloride, carbon dioxide, and water. The balanced chemical equation for this reaction is: 2HCl + MgCO3 → MgCl2 + CO2 + H2O.

CaCO3 + SiO2 ==Heat==> CaSiO3 + CO2

The products are calcium silicate and carbon dioxide.

When calcium carbonate is heated it undergoes thermal decomposition, to form calcium oxide(CaO) and carbon dioxide.

CaO is a base , because it is a metallic (Group 2) oxide. It reacts with SiO2 , which is an acidic oxide ( because it is a non-metallic (Group 4) oxide.

Remember a base plus an acid form a 'salt'. in this case CaSiO3 .

NB This is the side reaction going on in a blast furnace during iron oxide reduction. The reason for adding the 'flux' calcium carbonate (CaCO3) to remove the silicon dioxide impurity in the iron oxide.

NNB The carbon dioxide (CO2) is NOT released into the atmosphere, but undergoes reduction in excess coke (carbon) to form carbon monoxide (CO), which is the reducing agent of iron ore in the blast furnace.

Chlorine is the halogen that is in the same period as potassium. They are both in period 3 of the periodic table.

The halogens with their period no. are :-

Fluorine (2)

Chlorine (3)

Bromine (4)

Iodine (5)

Astatine (6)

Tennessine (7)

The last two are radio-active and not fully characterised. You will not find them in a school/college lab.

NB There are NO halogens in period '1'. The only elements in period '1' are hydrogen(H) and helium(He).

Under to process of electron affinity , they readily form anions.

As elements they are coloured. Yellow, green, brown, black/indigo, black.

As elements on going down the group they range from gas to liquid to solid. That is their m.p. & b.p. become higher on going down the group.

Do not conduct electricity

Poisonous.

They are all strongly electronegative

They all form 'chemical salts' with cationic metals. e.g. sodium chloride

The name 'halogen' means 'salt maker/generator' , and is from Classical Greece.

In one word 'YES'.

When the number of electrons and protons differ, it is no longer an atom, but an ION.

e.g.

Sodium atom (Na) has 11 protons, 12 neutrons and 11 electrons.

Sodium ion (Na^(+)) has 11 protons, 12 neutrons and 10 electrons.

Note the number of protons and electrons in the atom is the same at '11'.

Note also the number of protons differs from the number of electrons in the sodium ion at 11 protons and 10 electrons.

NNB When the number of neutrons differs , it is NOT a different atom/element, but an isotope of the same element.

None!!! There is no such substance as ' CaCL2 '.

There is no element with the symbol 'L'.

However, if you mean ' CaCl2 .

Then one molecule contains three atoms .

viz:

1 x Ca (Calcium)

2 x Cl( Chlorine).

The prefix '3' means three molar ratios. , or three molecules.

So in three molecules of CaCl2 there will be 3 x 3 = 9 atoms.

Archaically ; Sodium oxalate

IUPAC ; Sodium ethandiotate

Structurally, ; Na...O-(O=)C-C(=O)-O...Na

YES!!!

Any metal cation ionically combined to an acidic anion is a salt.

Sodium oxalate is the archaic name for sodium ethandioate.

Structurally,.

Na^(+) (-)O-(O=)C-C(=O)-O^(-) Na^(+)

Notice there are two sodium cations, one each at either end of the ethandioate anion.

'co' is neither a compound nor an element. Chemically it does NOT exist.

'CO' is the compound Carbon Monoxide ; a combination of carbon and oxygen.

'Co' is the element Cobalt ; found in the Periodic Table.

NB

Single letter elemental symbols are always written as a CAPITAL letter.

Double letter elemental symbols are written as ; first letter is a CAPITAL letter and the second letter is small/lower case letter.

There are NO elements/compounds with lower case letters throughout.. They DO NOT exist.

This is the international standard, and recognised world-wide.