Elements and Compounds

No, Iron is a homogeneous mixture as long as the iron is pure

Depends on the oxidation state of iron.

Iron(II) chloride ; FeCl2 ; Ferrous chloride

Iron(III) chloride ; FeCl3 ; Ferric Chloride.

LiBr is 'lithium bromide'

The number of neutrons can vary, depending on the Atomic Mass.

For any given element the number of protons ALWAYS remains the same. The number of neutrons can vary ; this being an isotope.

So you can have lithium six ; Li-6 ' [6/3]Li

or

lithium seven ; Li-7 ; [7/3]Li

The formula are incorrect, and the charges are NOT balanced.

The redox reaction is

Cl2 + 2Br^(-) = 2Cl^(-) + Br2

Remember the aide memoire, OILRIG.

OIL ; **Ox**idation Is Loss of electrons

RIG ; **Red**uction Is Gain of electrons.

RedOx is a reaction that occurs simultaneously. One component is reduced ,and the other component is oxidaised.

Above

Chlorine gas is Reduced. It has gained electrons, to form the chloride ion

The half eq'n is Cl2(g) + 2e^(-) = 2Cl^(-)

Simultaneously and 'vice versa'

The Bromide ion has been oxidised, lost electrons , to form elemental bromine.

The half eq'n is 2Br^(-) = Br2 + 2e^(-)

Water (H2O) and carbon dioxide (CO2) are two common compounds that include oxygen.

They are both 'Common'.!!!!

Water is a compound

Air is a mixture.

Acid ; Hydrochloric Acid

Base ; Sodium hydroxide.

Here is the balanced chemical reaction.

HCl(aq) + NaOH(aq) = NaCl(aq) + H2O(l)

NO!!!

Here are the general acid reaction.

Acid + Base = Salt + Water

Acid + Alkali = Salt + Water

Acid + metal = Salt + Hydrogen

Acid + Carbonate = Salt + Water + Carbon Dioxide.

NB In none of then is oxygen produced.

NNB The salt is a chemical salt of the form (MA) of which table salt is one. 'M' being the metal cation and 'A' acid anion.

THere are several nitrogen/oxygen compounds.

Viz.,

NO2 ; Nitrogen dioxide (Oxid'n state 4)

NO ; Nitrogen monoxide (Oxid'n state 2)

N2O ; Nitrous oxide (Laughing gas). (Oxid'n state 1)

The different is in the oxidation state of nitrogen , as given alongside each.

Only WATER (H2O) .

Compounds are molecules that contain atoms of different elements.

Nitrogen (N2) , Oxygen(O2) and Hydrogen(H2) are molecules, but NOT compounds, because they only contain atoms of one element.

Oxygen (O2) is a MOLECULE of two atoms of the element oxygen. It is found in the atmosphere.

Water(H2O) is a compound. It is a combination of two atoms of hydrogen and one atom of oxygen.

NB A compound is a molecule that contains atoms of two or more different elements.

So both Water and Oxygen are molecules.

However, only water, in this case, is a compound.

Hexane is both Organic, an Hydrocarbon and an alkane.

Organic because it contains carbon. in the structure.

Hydrocarbon because it contains only atoms of the elements hydrogen and carbon.

An Alkane because it only has single bonds between carbon .

In the nomenclature (naming system) ' Hex' '6' carbons and '--ane' an alkane..

Structurally, hexane is ' CH3-CH2-CH2-CH2-CH2-CH3 '.

Yes, a compound with the chemical formula C15H30 would be a member of the alkane series. Alkanes have the general formula CnH2n+2, where n represents the number of carbon atoms in the alkane molecule. In this case, n=7, so the compound falls into the alkane series.

An ALK**Y**NES

Structurally, ' R - C///C - R'

Lithium is a natural element.

However, it is NOT found as the 'pure' metal, but as the cation ' Li^(+) '.

The synthetic elements are the Trans-Uranic elements, with atomic No. greater than '100'.

Iron, because it is a transition metal .

The other three are all Group (I) Alkali metals.

NO!!!!

Lithium is the first of the Group (I) alkali metals.

The Transitional metals. are in a block between Group (II) and Group (III).

The first periodic of Transition metals is Scandium to Copper.

YES!!!

The phrase 'Fatty Acid' has been superceded by 'Carboxylic Acid'.

Carboxylic Acid have the general formula, ' R-COOH '

In this general formula, there are two oxygen atoms.

Yes, all samples of water have the same composition of hydrogen and oxygen, with each water molecule containing two hydrogen atoms and one oxygen atom. This is consistent regardless of the source or location of the water.

The Carbonate anion has four atoms.

1 x carbon

3 x oxygen

Giving the formula ' CO3^(2-)' It does NOT exists in its own right as a substance, but in combination with a metal. e.g. CaCO3 Calcium carbonate.

As many as you like!!!!!

Different substances have a different number of hydrogen atoms in their formula.

e.g.

Water ; H2O ; 2 hydrogen atoms

Ammonia ; NH3 ; 3 hydrogen atoms.

Methane ; CH4 ; 4 hydrogen atoms.

The polymer 'polypropylene' can have millions of hydrogen atoms.

NO such substance as ' h3po4 '.

If you mean ' H3PO4 '. , then there are eight(8) atoms.

3 atoms of hydrogen

1 atom of phosphorus ( '1' is never shown in chemical formulae ).

4 atoms of oxygen .

3 + 1 + 4 = 8

NB When writing formula, single letter elemental symbols are ALWAYS a CAPITAL letter.

Hence hydrogen is 'H' ; not 'h'

phosphorus is 'P' ; not 'p'

Oxygen is 'O' , not 'o'

This is the international IUPAC standard and as shown in the Periodic Table.

It is done to avoid confusion between say ' CO' and 'Co'. which are two different substances.

Two letter elemental symbols are written as , first letter is a CAPITAL letter and the second letter is small/lower case. e.g. ' Na ' sodium '.

So ' h3po4 ' is totally incorrect and meaningless.

ONE (1)

The formula ' H3PO4 '. tells that there are ;=

3 atoms of hydrogen

1 atom of phosphorus ( '1' is never shown as a number in any substance).

4 atoms of oxygen .

The numbers are written sub-script after the given elemental symbol.

First of all H3PO4 is NOT an Element.

It is a compound, composed of three elements viz., hydrogen , phosphorus, and oxygen.

H3PO4 is phosphoric acid .