Which one of the following is a reversible change?
Ripening of fruits
Curdling of milk
Folding of paper
Burning of paper
Sublimation of iodine is an example of ______ change .
physical
chemical
exothermic
none of these
Which one of the following is an example of physical change in nature?
Chemical weathering
Nitrogen cycle
Erosion
Carbon cycle.
Anaerobic bacteria digest animal waste and produce biogas(Change-A). The biogas is then burnt as fuel (Change-B). The following statements pertain to these changes. Choose the correct one.
Process- A is a chemical change
Process- B is a chemical change
Both process- A and B are chemical changes
None of these process is a chemical change
Which of the following is a chemical change?
Painting wood
Burning paper
Sugar dissolving in water
Iron turning red when heated
Which one of the following is NOT a physical change?
Mixing salt and pepper
Mixing salt and water
Mixing sugar and water
Mixing sand and iron nails
Which of the following is a chemical change ?
Germination of seed
Formation of coal from the wood
All of these
In which one of the following examples heat produces no change in chemical composition?
Burning of magnesium
Decomposition of zinc carbonate
Burning of Sulphur
Magnetization of iron piece
Expansion and contraction is done by
heating
mixing
cooling
both heating and cooling
Which of the following is a physical change ?
Melting of ice
Melting of wax
Formation of steam from water
