Test : Atoms And Molecules- 2

 it  will be incorrect to say that  an  atom of  a compound   because, 
Every combination of atoms is a molecule. A compound is a molecule made of atoms  from different elements. All compounds are molecules , but not all molecules are compounds.

Option 2 illustrates the law of conservation of mass.

The law of conservation of mass states that in a chemical reaction, the total mass of the reactants is equal to the total mass of the products. This means that matter is neither created nor destroyed in a chemical reaction.

In option 2, 12 g of CO reacts with 32 g of O2 to form 44 g of CO2. The total mass of the reactants (12 g + 32 g = 44 g) is equal to the total mass of the product (44 g). This illustrates the law of conservation of mass.

Option 1 is an example of the law of definite proportions, which states that a given compound always contains the same elements in the same proportion by mass.

Option 3 is not a valid example of the law of conservation of mass, as heating carbon in a vacuum can lead to the release of gases such as carbon dioxide, carbon monoxide, and carbon suboxide, which can escape and change the mass of the system.

Option 4 is an example of a physical change, where the state of matter of a substance changes, but the mass of the substance remains the same. It does not illustrate the law of conservation of mass.

In 1806, Proust summarized his observations in what is now called Proust's Law. It stated that chemical compounds are formed of constant and defined ratios of elements, as determined by mass. For example, carbon dioxide is composed of one carbon atom and two oxygen atoms.

The compound Sulphur = 8%
Therefore, 8g of S is present in 100g.
(Least molecular mass means that at least one atom of Sulphur should be present in a molecule.)
Therefore, 32g of S is peasant in 100/8 x 32 = 400

Mass of one atom = Avogadro′s numberMass of one mole of atom​=12/6.02×10²³

Mass of one carbon atom = 1.994×10⁻²³g

option ( c) The mixture has properties similar to its compound is the correct answer. 

Explanation:- 

This is because in a mixture, the constituent particles are not mixed chemically.
They are mixed physically and can be separated fairly easily by physical Methods.
Thus they show the properties of components.
Example can be alloys.

N₂ is the chemical symbol for nitrogen gas.

Molar mass of sucrose = 342 g
No. of Oxygen atoms in 3.42g of (C₁₂H₂₂O₁₁) = 11 x NA
Therefore, No. of Oxygen atoms in 342g of (C₁₂H₂₂O₁₁) = 11 x Na x 3.42 / 342
= 0.11 NA
No. of oxygen atoms in 18g of H₂O = 1NA 
Therefore, Total no. of Oxygen atom in 342g of Sucrose and 18g of water 
= 0.11NA +1NA = 1.11NA = 1.11 x 6.02 x 10²³ ⇒ 6.68 * 10²³

option ( b) is the correct✔ answer. 

Explanation:- first we have to calculate, the no. of molecules  and then we will compare them. To calculate the number of molecules, we multiply no. of moles with the Avagadro's number. 

• 0.5 *( 6.022 * 10^23) 

=  3.11 * 10^ 23

• 2* ( 6.022 * 10^23) 

=  12.044 * 10^ 23

• 3.35 * 10^19

• 0.05 * ( 6.022 * 10^23) 

= 0.3011 * 10^ 23

So, we can see, 4<1<3<2   is the correct✔ answer.

Because , the symbol used for aluminum is Al,  the symbol used for carbon is C,  the symbol used for cobalt is Co.