Question

why is CO2 a gas at room temperature,while SiO2is a solid??? please answer fast and thank you.

Answer 1

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CO2 exists as a discrete single molecule as O=C=O. and due to only van der waal's interactions the intermolecular forces are not strong enough, allowing the molecules move about freely, hence it exists as a gas.

SiO2 however actuall exists as a polymeric network as O-Si-O-Si......., here each Si atom is bonded to O atom by a single bond and also to 2 other O atoms making it strongly bonded. Due to this the intermolecular forces are tremendously high and molecules cannot move about freely, Hence SiO2 is a solid.

Answer 2

Answer:

The reason why carbon dioxide is a gas and silicon dioxide is a solid is because their chemical structures are different. Carbon dioxide is a linear structure with two double bonds between carbon and oxygen. It is a small molecule and non-polar with only weak bonds between the molecules.