How many moles of atoms are present in 9.0 g of aluminum?

How can you prove that red oxide of copper is not an element ?

What physical meaning is attributed to the square of the absolute value of wave function \(|\psi |^{ 2 }\)?

Write the number designation of a group that has 2 electrons beyond a noble gas configuration.

What is a spontaneous change? Give one example.

Name a substance which can oxidise H₂O₂.

Why do the C- C bonds rather than C - H bonds break during cracking of alkanes?

List gases which are reponsible for green house effect.

Explain why is there a phenomenal decrease in ionisation enthalpy from carbon to silicon?

In the estimation of sulphur by carius method 0.468 of an organic sulphur compound afforded 0.668 g of barium sulphate. Find the percentage of sulphur in the given compound.

Rotation around carbon-carbon single bond of ethane is not completely free. Justify the statement.

What is the use of recycled waste?

Consider structure I to VII and answer the following questions (i) and (ii).
I. \({ CH }_{ 3 }-{ CH }_{ 2 }-{ CH }_{ 2 }-{ CH }_{ 2 }-{ OH }\) 
II.
\({ CH }_{ 3 }-{ CH }_{ 2 }-{ CH }-{ CH }_{ 3 }\\ \quad \quad \quad \quad \quad \quad \quad |\\ \quad \quad \quad \quad \quad \quad \quad { OH }\)  
III.
\({ \quad \quad \quad \quad CH }_{ 3 }\\ \quad \quad \quad \quad |\\ { { CH }_{ 3 } }-{ C }-{ CH }_{ 3 }\\ \quad \quad \quad \quad |\\ \quad \quad \quad \quad { OH }\) 
IV.
\({ CH }_{ 3 }-{ CH }-{ CH_{ 2 } }-{ OH }\\ \quad \quad \quad \quad |\\ \quad \quad \quad \quad { CH }_{ 3 }\) 
V. \({ CH }_{ 2 }-{ CH }_{ 2 }-{ O }-{ CH }_{ 2 }-{ CH }_{ 3 }\)
VI.
\({ CH }_{ 2 }-{ O }-{ CH }_{ 2 }-{ CH }_{ 2 }-{ CH }_{ 3 }\) 
VII.
\({ CH }_{ 3 }-{ O }-{ CH }-{ CH }_{ 3 }\\ \quad \quad \quad \quad \quad \quad |\\ \quad \quad \quad \quad \quad \quad { CH }_{ 3 }\) 
Identify the pairs of compounds that represent chain isomerism.

An alkane has a molecule mass of 72. Give all the possible structural isomers along with their IUPAC names.

What are pesticides and herbicides? Explain giving examples.

What are the harmful effects of photochemical smog and how can they be controlled?

A compound made up of two elements A and B has A = 70%, B = 30%. Their relative number of moles in the compound are 1.25 and 1.88. Calculate molecular formula of the compound, if its molecular mass is found to be 160.

An alloy of iron (53.6%), nickel (45.8%) and manganese (0.6%) has a density of 8.17 g cm^-3. Calculate the number of Ni atoms present in the alloy of dimensions 10.0 cm x 20.0 cm x 15.0 cm.

Justify the given statement with suitable examples "the properties of the elements are a periodic function of their atomic number".

Discuss the shape of the following molecules using the VSEPR model: BeCl₂, BCl₃, SiCl₄, AsF₅, H₂S, PH₃

Apart from tetrahedral geometry, another possible geometry for CH₄ is square planar with the four H atoms at the corners of the square and the C atom at its centre. Explain why CH₄ is not square planar ?

Justify that the following reaction are redox reaction
\(4BCl_{ 3 }(g)+3LiAl{ H }_{ 4 }(s)\longrightarrow 2{ B }_{ 2 }{ H }_{ 6 }(g)+3LiCl(s)+3AlC{ l }_{ 3 }(s)\)

Complete the following chemical reactions and classify the above into (a) hydrolysis,(b) redox and (c) hydration reactions.
\(PbS(s)+{ 4 }H_{ 2 }{ O }_{ 2 }(aq)\rightarrow \)

Why cannot sodium and potassium ne prepared by the electrolysis of their aqueous solutions ?

Arrange the following set of compounds in order of their decreasing relative reactivity with an electrophile, E+.
(i) Chlorobenzene, 2, 4-dinitrochlorobenzene, p-nitrochlorobenzene
(ii) Toluene,  \(p-{ H }_{ 3 }C-{ C }_{ 6 }{ H }_{ 4 }-{ NO }_{ 2 },\)
\(p-{ O }_{ 2 }N-{ C }_{ 6 }{ H }_{ 4 }-{ NO }_{ 2 }\)
Also explain ur answer.

Discuss the preparation of alkanes by Wurtz reaction. What is the limitation of the reaction?