Give reason-
Ice floats on water near the melting point.
Copper is ductile and malleable but brass is not.
Latent heat of fusion of solid co2 is much less than that of silicone dioxide.
pls ans asap...have my exams tom.
Sure! I'll provide you with the reasons for each of the given statements.
1. Ice floats on water near the melting point because of its unique molecular structure. Unlike most substances, water expands as it freezes. When water molecules freeze and rearrange into a solid crystal lattice, they form an open and hexagonal structure with empty spaces. Due to this open structure, the density of ice is less than that of liquid water. As a result, ice is less dense and floats on top of the liquid water.
2. Copper is ductile and malleable because of its metallic bonding nature. Metallic bonding occurs when positive metal ions are surrounded by a "sea" of delocalized electrons. These electrons are free to move within the lattice. This arrangement allows the metal ions to easily slide past one another when a force is applied, making copper ductile (able to be drawn into wires) and malleable (able to be hammered into thin sheets). On the other hand, brass, which is an alloy made of copper and zinc, has a different crystal structure that hinders the movement of atoms when force is applied. This makes brass less ductile and malleable compared to pure copper.
3. The latent heat of fusion of solid CO2 (dry ice) is much less than that of silicon dioxide (silica or quartz). Latent heat of fusion refers to the amount of energy required to change a substance from a solid to a liquid state at its melting point, without changing its temperature. Solid CO2 has weak intermolecular forces, also known as van der Waals forces, which are relatively easier to overcome. This leads to a lower energy requirement for the phase change from solid to liquid, resulting in a lower latent heat of fusion. On the other hand, silicon dioxide has strong covalent bonds between the silicon and oxygen atoms, requiring more energy to break those bonds during fusion, leading to a higher latent heat of fusion.
Remember to review these explanations and understand the concepts before your exams. Good luck!