3.3 kg aluminum chromate

Methane and ethane demonstrate the law of definite composition and the law of multiple proportions as these both compounds have the exact atoms but in different ratios.  

As for methane, it can be seen that every methane molecule contains 4 hydrogen atoms and 1 carbon atom. Where masses of carbon and hydrogen are in ratio - 12 g C / 4 g H -- reduce to 3g C/ 1 g H .

Ethane contains 2 carbon atoms and 6 hydrogen atom and their mass ratio will be  - 24 g C / 6 g H -- reduce to 4 g C/ 1 g H .

So both ethane and methane demonstrate the law of definite composition and the law of multiple proportions.

Law of definite composition: The elements which are present in the compound is combined in the same proportion by mass.

Law of multiple proportion: When two or more compounds are formed by the combination of two elements then the mass ratio of one element is combined with the fixed mass of the other element.

In case of methane, it consist of one carbon atoms and four hydrogen atoms implies that has definite composition. In terms of mass, in methane, carbon and hydrogen atoms are combined in a definite ratio i.e. 12 g C/ 4 g H. Thus, methane has definite composition.  

Now, carbon and hydrogen combines to give a class i.e. hydrocarbon. In this case, for every constant mass of carbon the ratio of hydrogen will always reduce to 4/3 ratio for the formation of ethane (hydrocarbon). Thus, law of multiple proportion followed.

Similarly, in case of ethane, this compound also consist of exact atoms but in different ratios.

In case of ethane, it consist of two carbon atoms and six hydrogen atoms implies that has definite composition. In terms of mass, in ethane, carbon and hydrogen atoms are combined in a definite ratio i.e. 24 g C/ 6 g H. Thus, methane has definite composition.  

Now, carbon and hydrogen combines to give a class i.e. hydrocarbon. In this case, for every constant mass of carbon the ratio of hydrogen will always reduce to a specific ratio for the formation of methane (hydrocarbon). Thus, law of multiple proportion followed.

Answer: We are able to smell it because the particles move from their high concentration to low concentration and mix with the gases present in the atmosphere and thus we are able to smell it.

Diffusion is a process in which a movement of substance takes place from a high concentration area to a low concentration area due to the random movement of the particles. Diffusion happens in gases more faster than liquids and solids because of the random movement of their particles.

Other substances exhibiting this behavior is perfume, incense sticks and cooking of food etc.

Answer is: (2) Energy is absorbed and a bond is broken.

This energy is called bond-dissociation energy.

Bond-dissociation energy is the measure of bond strength in a chemical bond.

Bond energy of bromine molecule (sigma bond) is energy needed for breaking up one molecule of bromine into two bromine atoms.

When two bromine atoms (Br) form molecule of bromine (Br₂), than energy is released and bond is formed.

there is no answer

because everyone is perfect in their own way

;)