all physical changes are reversible and only chemical changes are irreversible do you agree give reasons and examples - science - changes around us
all physical changes are reversible and only chemical changes
are irreversible do you agree?give reasons and examples
hi,
all physical changes are not
reversible cutting of tree is an irreversible physical change
all chemical changes are not
necessarily irreversible

the reaction between hydrogen and oxygen to form water is an
example reversible chemical reaction the reaction can be
represented as:
h2 + 1/2 o2→ h2o
we’re being asked which of the following conditions occurs when a chemical change happens to a piece of wood let’s first define a physical change and a chemical change.physical change → there is a change in a matter as it goes from one physical state to another.chemical change → atoms rearrange themselves to create a new substance. now, let’s take a look at each condition:[readmore]a. is splitsplitting wood is only reducing its size. physical changeb. is paintedpainting wood is only placing paint on top of it and not really affecting the composition of the wood.  physical changec. decaysdecaying changes the integrity of the wood itself and transforms it into things like soil. chemical changed. is cutcutting wood is only reducing its size. physical changea chemical change occurs when a piece of wood c. decays. recycling is nothing but rehabilitating the use of old and used items by redoing. e.g., plastics. melt again and cast and reuse.
similary waste and thrown of materials such as tins and cans also can be recycled by reproducing useful materials from them.
drain water is treated and recycled for use. oil from drains of industries are stored and reclailmed and used after mixing up chemcials to get back the qualities required.
in all the cases, either for lesser important uses or for the same use itself can be had, depending upon the qualilty of recycled product. thus waste othewise thrown out can be recycled, by duly segregating them for a particular recycling use, known as waste management. e.g. plastics. papers, steel and ferrous items. non-ferrous metals, acids, rubber etc. segregated for recycling.
vr pure substances are made up of same type of particles or atoms. all the elements and compounds are pure substances because they contain the same kinds of particles. examples: hydrogen, carbon dioxide The physical and chemical properties of elements depend on the number of valence electrons. Elements present in the same group have the same number of valence electrons. Therefore, elements present in the same group have similar physical and chemical properties. chemistry 1010 study guide classify the following properties as intensive or extensive: intensive- doesn’t change (boiling point, temp, color, density, hardness) extensive- changes in size/ amount (volume, mass length scientific method terms experiment: a well-controlled procedure used to obtain data in order to describe a phenomenon. law: a statement that describes natural phenomenon by summarizing collected facts. observation: a statement describing a natural phenomenon that we sense. scientific fact: a statement that is explained by reproducible experimental data hypothesis: guesses that is not verified yet. mass and weight mass is a measurement of the quantity of matter in an object, whereas weigh is a measurement of the force of gravity on the matter of an object; ther 1. according to kinetic theory of ideal gases, molecules of a gas are in incessant random motion, colliding against each other and with the walls of the container. all these collisions are perfectly elastic collision.2. in perfectly elastic collision, total kinetic energy of gas is conserved.3. here, we have a mixture of oxygen and hydrogen gas. thereforek.e of oxygen + k.e of hydrogen=constant4. so, if kinetic energy of oxygen molecules increases, then kinetic energy of hydrogen molecules decreases or vice-versa so that, sum of both kinetic energies remains constant.5. therefore, both option (c) and (d) are correct. trueexplanation: physical balance is very sensitive and used in labs for measuring. it is similar to beam balance. it can measure small differences in mass up to milligram. 1. introduction: rough surface in contact i. surface of engineering materials: generals  surfaces have chemical properties, which are different from bulk virgin material. o most metallic surfaces in air have oxide layers, which change the chemical and mechanical properties of the surfaces.  surfaces have mechanical properties, which are different from bulk material. o machining or sliding contact makes strain hardened (or work hardened) layer and highly deformed layer, whose strength are different from bulk.  real engineering surfaces are rough. mirror like smooth surface afm image a1. (i) we can only fail if we give up or stop trying.(ii) we need to accept our faults and take it as a learning because no one is perfect.(iii) failures are the experiences that we get to ensure that they are not repeated ahead.(iv) only when you participate and give a try you come to know the positives and negatives about it.(v) it's not about how many times you have failed but after that how many times you stood up is what really matters. a2. the example of refrain (repetition) from the extract is-you may be the person i am looking for.refrain is identified easily as these lines are repeated in the poem & usually towards the end. a3. ideal persons are the ones who are always demanded by people. majority of people have their role model in life whom they follow or want to become like them. though we know that no one is perfect in this world but ideal person has a best quality in them that is positive approach towards life. a4. and consider everyone like their brothers. its relatively price inelastic because, its almost a necessity, and by definition, necessities are said to be price inelastic.