Question

tick the correct answer
1.A chemical change may involve:
a)Change in colour only b)change in temperature only c)Evolution ofgas only
d)any or all of the above

2.Which of the following is/are true when milk changes into curd?i.Its state is changed from liquid to semi-solidii.It changes colouriii.It changes tasteiv.The change cannot be reversedChoose the correct option from below:a)(i) and (ii) are correctb)(ii) and (iii) are correctc)(i), (iii), and (iv) are correctd)(i) and (iv) are correct3.Rohit’s mother made a concentrated sugar syrup by dissolving sugar in hot water. On cooling, crystals of sugar got separated. This indicates a:a)Physical change that can be reversedb)Chemical change that can be reversedc)Physical change that cannot be reversedd)Chemical change that cannot be reversed4.Which of the following is incorrect for a chemical reaction?a)Heat may be given out but never absorbedb)Sound may be producedc)A colour change may take placed)A gas may be evolved5.The rusting of ships occursbecause:a)The body of ship is always in contact with water.b)The air around the ship is humid.c)Presence of salts in sea water speed up the process of rusting.d)All of the above
Page 3of 56.Expansion on heating and contraction on cooling of metals is a:a)Chemical change that can be reversed b)Physical change that can be reversedc)Chemical change that cannot be reversedd)Physical change that cannot be reversed7.Which of the following statements is correct?a)Evaporation is a chemical changeb)Digestion of food is a chemical changec)Burning of paper is a physical changed)All of the above8.In which one of the following situations chemical reaction doesnot occur?a)Common salt is exposed to airb)Coal is burnt in airc)Sodium is placed in waterd)Iron is kept in moist air9.Glowing of an electric bulb is a ________ change.a)Physical and reversibleb)Chemicalc)Both physical and chemicald)Physicaland irreversible10.Liquefied Petroleum Gas (L.P.G) used as kitchen fuel is supplied in the liquid form in the gas cylinders. When it comes out from cylinder it comes out as a gas which bums. Which of the following statements is correct?a)The process of conversion of liquid to gas involves a chemical change.b)The process of burning gas is a chemical change.c)Both the above are correct.d)None of these11.Anaerobic bacteria digest animal waste and produce biogas (ChangeA). The biogas is then burnt as fuel (Change B). The following statements are related to these changes. Choose the correct one.a)A is a chemical change whereas B is a physical change.b)B is a chemical change whereas A is a physical change.c)Both A and B are physical changes.d)Both A and B are chemical changes.

Answer 1

Answer:

sorry i do not known this answer

Answer 2

Answer:

1.d)any or all of the above