Question

(a)
(b)
State any one postulate of Daltons atomic theory & mention the draw
back or limitation for the same postulate.
When 15g of copper sulphate react with 15g of sodium hydroxide, 20g
of sodium sulphate along with copper hydroxide is formed. What is the
mass of copper hydroxide formed ?​

Answer 1

★Question(1) :

State any one postulate of Daltons atomic theory & mention the drawback or limitation for the same postulate.

Answer(1) :

Postulates of Dalton's atomic theory

• Matter Consists of indivisible particles called atoms

Drawback : Atom is a divisible particle which can be further broke down into particles called as electron , proton and neutron

• Atoms of same element exhibit similar properties but vary from the atoms of other elements

Drawback : Atoms of same elements show different masses and densities

━━━━━━━━━━━━━━━━━━━━━━

★Question(2) :

When 15g of copper sulphate react with 15g of sodium hydroxide, 20g of sodium sulphate along with copper hydroxide is formed. What is the mass of copper hydroxide formed ?

Concept used :

• The total mass of the reactants should be equal to the total mass of the products . This is known as ' Law of conservation of mass '

Answer(2) :

Reaction ,

${\rm{CuSO_{4}+NaOH\longrightarrow\:NaSO_{4}+ Cu(OH)_{2}}} \\ \\ \: \: (15g) \: \: \: \: \: \: \: \: (15g) \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: (20g) \: \: \: \: \: \: \: \: \: \: \: ({\rm{x}}g )\:$

Let the mass of Cu(OH)₂ formed be ' x ' g

According to Law of conservation of mass ,

Total Mass of Reactants = Total mass of products formed

This mean ,

Mass of CuSO₄ + Mass of NaOH = Mass of NaSO₄ + Mass of CuOH

$: \implies \rm \: 15 \: g + 15 \: g = 20 \: g + x \: \\ \\ : \implies \rm \: 30g = 20 \: g + x \: \\ \\ : \implies \rm \: 30 \: g - 20 \: g = x \: \\ \\ : \implies \rm \: 10 \: g = x \\ \\ : \implies \rm \: x = 10 \: g \: \bigstar$

Answer 2

Answer:

★Question(1) :

State any one postulate of Daltons atomic theory & mention the drawback or limitation for the same postulate.

Answer(1) :

Postulates of Dalton's atomic theory

Matter Consists of indivisible particles called atoms

Drawback : Atom is a divisible particle which can be further broke down into particles called as electron , proton and neutron

Atoms of same element exhibit similar properties but vary from the atoms of other elements

Drawback : Atoms of same elements show different masses and densities

━━━━━━━━━━━━━━━━━━━━━━

★Question(2) :

When 15g of copper sulphate react with 15g of sodium hydroxide, 20g of sodium sulphate along with copper hydroxide is formed. What is the mass of copper hydroxide formed ?

Concept used :

The total mass of the reactants should be equal to the total mass of the products . This is known as ' Law of conservation of mass '

Answer(2) :

Reaction ,

\begin{gathered}{\rm{CuSO_{4}+NaOH\longrightarrow\:NaSO_{4}+ Cu(OH)_{2}}} \\ \\ \: \: (15g) \: \: \: \: \: \: \: \: (15g) \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: (20g) \: \: \: \: \: \: \: \: \: \: \: ({\rm{x}}g )\: \end{gathered}

CuSO

4

+NaOH⟶NaSO

4

+Cu(OH)

2

(15g)(15g)(20g)(xg)

Let the mass of Cu(OH)₂ formed be ' x ' g

According to Law of conservation of mass ,

Total Mass of Reactants = Total mass of products formed

This mean ,

Mass of CuSO₄ + Mass of NaOH = Mass of NaSO₄ + Mass of CuOH

\begin{gathered} : \implies \rm \: 15 \: g + 15 \: g = 20 \: g + x \: \\ \\ : \implies \rm \: 30g = 20 \: g + x \: \\ \\ : \implies \rm \: 30 \: g - 20 \: g = x \: \\ \\ : \implies \rm \: 10 \: g = x \\ \\ : \implies \rm \: x = 10 \: g \: \bigstar\end{gathered}

:⟹15g+15g=20g+x

:⟹30g=20g+x

:⟹30g−20g=x

:⟹10g=x

:⟹x=10g★