solutionsGrade 7ChemistryChapters in Simplified Middle School Chemistry - CLASS 7Exercises in Matter and its CompositionQuestion 8Q8)Give a reason why -(a) Solids have a definite volume & a definite shape.(b) Liquids have a definite volume but no definite shape.(c) Gases have no definite volume and no definite shape.Solution :(a) Solids have definite shape and definite volume because the molecules in solid are CLOSELY packed and in FIXED positions. The molecules can vibrate but do not move around which keeps the shape and volume definite.(b) Liquids have no definite shape but definite volume because the molecules in liquid are not so closely packed and they have space between them. The molecules can move around and the forces of attraction between molecules is less as compared to solids, so the liquid takes the shape of the container and volume is definite.(c) Gases do not have a definite shape or volume because the molecules in gases are very loosely packed, they have large INTERMOLECULAR spaces and hence they move around. The force of attraction between molecules is also very less, as a RESULT gases acquire any shape or any volume.