Chemistry Questions

A substance that cannot be decomposed (broken down) into simpler substances by ordinary chemical means.

Examples: gold, iron, carbon, hydrogen, oxygen, nitrogen.

Material composed of only one kind of matter throughout (same atoms or same molecules).

Covalent bonds hold atoms together because the attraction between the positively charged nuclei and the negatively charged shared electrons is greater than the repulsions between the nuclei themselves.

A mixture is made from different substances that are not chemically joined.Compound:

•Two or more elements combine together chemically to form a new substance called compound.

•The different elements are chemically joined together.•Compounds are homogeneous, i.e. their properties are the same throughout

•The compound has properties different from the elements it contains.

•It can only be separated into its elements using chemical reactions. (not using physical methods)

•During the formation of a compound from its elements, a certain amount of energy in the form of heat, light, electricity is either absorbed or evolved

In chemistry, the term transition metal has three possible meanings: The IUPAC definition defines a transition metal as "an element whose atom has a partially filled d sub-shell, or which can give rise to cations with an incomplete d sub-shell".

Any of the set of metallic elements occupying a central block (Groups IVB–VIII, IB, and IIB, or 4–12) in the periodic table, e.g. iron, manganese, chromium, and copper. Chemically they show variable valency and a strong tendency to form coordination compounds, and many of their compounds are coloured.

Here in the given options, only iron (Fe) is a transition metal since Strontium is an alkaline earth, arsenic is a metalloid, hydrogen is (normally) a diatomic gas.

In the bond formation of barium with oxygen, the valency electrons from the barium transferred to the oxygen and forms an ionic bond.

Chemical Compounds with stronger intermolecular forces have higher boiling points.

The order of strengths of intermolecular forces is:

 London dispersion < dipole-dipole < H-bonding

${\text{Methane (CH}}_{\mathrm{4)}}$ — London dispersion forces

${\text{Dimethyl ether (CH}}_3{\text{OCH}}_{\mathrm{3)}}$ — dipole-dipole attractions

${\text{Methanol (CH}}_3\text{OH)}$ — hydrogen bonding

Therefore, ${\text{Methanol -}}^{}$${\text{CH}}_3\text{OH}$$\text{with H-Bonding have highest Boiling Point among the given chemical compounds.}$

Stainless steel contains 18% chromium and 82% steel