Question

Will anyone give me some of the imp. Q. From the chapter of atoms and molecules ,structure of atom ,work and energy and gravitation
WITH ANSWERS.

Answer 1

ATOMS AND MOLECULES
• what happens in a chemical reaction ?
• What is the main difference between elements and compounds?
• why do we cover the apparatus during an experiment ?
• Name the scientists who proposed the basic principles in the laws of chemical combination? Write both of them.
• write an activity to prove law of conservative of mass
• Explain Dalton's atomic theories along with the drawbacks.
• define atoms and molecules
• what is the relation between m and nm
• Define 1u
• Earlier oxygen was taken as standard for measuring the mass of an atom and why ?
• what is atomacy
• give example of different types of atoms and compounds
• what r ions ? what r polyatomic ions ?
• define 1 mole
• differentiate between molar mass and molecular mass
• which is the Avogadro Number

STRUCTURE OF ATOM
• Explain J.J.Thomas's model of the atom. What r its drawbacks ?
• Explain Rutherford's model of an atom? What r its observations? What r its features? and what r the drawbacks?
• Explain Nel Bohr's model of an atom. Explain its stability.
• why did Rutherford took a gold foil?
• what is electronic configuration?
• what is atomic no.?
• what is meant by atomic mass of an element ?
• What is valency ?
• what r isotopes and isobars? give examples
• write isotopes of hydrogen, chlorine and carbon
• why does isotopes have same chemical properties ?
• why does isotopes have different physical properties?
• calculate the average atomic mass of chlorine atom
• write the applications of isotopes
• summarize the rules for writing of distribution of electrons in various shells

WORK AND ENERGY
• what r the conditions necessary to say that work is done ?
• what is work ? what is its unit ?
• define the SI unit of work?
• What r the types of work? define them.
• the unit of energy and work done r same. why ?
• what's the expression for work ?
• what do u mean by energy.
• how can u say that sun is the ultimate source of energy? Name some types of energies where sun is not the ultimate source.
• define kinetic energy. derive an expression for it
• what is potential energy? write its 2 types. deduce an equation for it
• what is Mechanical energy? write an expression for it.
• what do u mean by law of conservative of energy.
• what is commercial unit of energy? find its relation to Joule
• define SI unit 1watt
• define average power.
• why should we have average power?

GRAVITATION ( FROM PG NO 138 ONWARDS)
• define thrust and pressure. what r their units ?
• define 1 pascal. what is its unit ?
• what is buoyant force ? what is buoyancy?
• what happens when pressure is applied on confined fluid? Explain with an example
• name the 2 forces acting on an object immersed in a fluid
• why do some objects float in water while others sink? Explain it in 2 ways
• how can u measure the vol of any irregular shaped obj ? how will u measure its density?
• how can u measure the vol of any irregular shaped obj that can float on water or fluid?
• density is character stick property of an obj. why ?
• what is Archimedes principle ?
• how can u find the buoyant force acting on an obj?
• what is relative density? what is its formula?

SOUND ( in addition )
• what is sound energy?
• what is compression and rarefaction? show it with the help of diagram
• define transverse wave and longitudinal wave
• what is mechanical wave? give example
• how can u prove that sound needs a medium to travel
• what is crest and trough
• what is frequency? what is its unit
• what is pitch? on which character stick does it depend?
• what is amplitude? what is its unit ?
• the unit of amplitude of sound is pa or kg/m³ or N/m². why?
• what is wavelength? what is its unit? how is it represented?
• what is time period? what is its SI unit ? how is it represented?
• what is relation between time period and frequency?
• write 2 formulas for finding velocity of a wave.
• what is an echo?
• what is least distance to here an echo? explain it
• what is reverberace ? how it can be reduced?
• what is a tone?
• what is note?
• what is intensity?
• what is loudness ?
• explain the uses of multiple reflection of sound?
• write the audible range of sound for human year.
• define ultrasonic and infrasonic sound.
• what r the applications of ultrasound?
• what is echo - ranging?
• what is a SONAR ?
• draw the well labeled diagram of human ear and explain it.
• How do bats predicts sound?

HOPE IT HELPS ^_^