GATE Questions

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The law of conservation of mass states that in any closed system the mass of the system is neither created nor destroyed over time i.e, the mass cannot be changed overtime.

Hence, the given statement is true.

In 2006, pluto devoted to a draft planet.

We know that most of the metals are goof conductors of electricity and heat. Metals are very strong but they are malleable i.e, they can be bent into a shape. These are shiny when they are cut or polished. 

Hence, metals are malleable, conductors and luster. All the above are properties of the metals.

Cricket World cup Year wise winners list from its starting year.

Year  -  Winner score

1975  -  West Indies 

1979  -  West Indies 

1983  -  India 

1987  -  Australia 

1992  -  Pakistan 

1996  -  Sri Lanka 

1999  -  Australia 

2003  -  Australia 

2007  -  Australia 

2011  -  India 

2015  -  Australia 

Australia won most number of titles i.e, 5 times Cricket World Cup title.

Polarity :: 

The polarity of a molecule defines its other physical properties such as melting point, boiling point, surface tension, vapor pressure etc... Simply, polarity occurs when the electron distribution in a molecule is asymmetric. This results in a net dipole moment in the molecule. One end of the molecule is charged negative while the other gets a positive charge.

The polarization of a molecule greatly depends on the shape of the molecule. A diatomic molecule like HF mentioned above has no issue of shape. The net dipole moment is only due to the uneven distribution of electrons between the two atoms. However, when there are more than two atoms involved in making a bond, there are many complexities.

The water molecule is of bent shape. Therefore, when the two pair of electrons shared by oxygen with two hydrogen atoms is pulled towards oxygen, the net dipole moment results in the direction of the oxygen atom. There is no other force to cancel out the resultant dipole moment. Hence, the water molecule is highly polar.

Ammonia molecule is of a pyramid shape and the electronegative N atom pulls the electrons towards itself. The three N-H bonds are not in the same plane; hence the dipole moments created do not get canceled out. This makes ammonia a polar molecule.

However, the dipole moments sometimes get canceled due to the shape of the molecules, making the molecule non-polar. Carbon dioxide is such a molecule.

Any properties that are dependent on the amount of matter are called as extensive properties of matter.

Examples are :: Mass, Volume, Density (M/V),...