Question 5 :
Rusting is a special term, given to the corrosion of which metal?

Question 8 :
A man painted his main gate made up of iron, toi) Prevent it from rusting.ii) Protect it from sun.iii) Make it look beautiful.<span>iv) Make it dust free.<br></span>

Question 9 :
The change which is permanent and can not be measured by just reversing the condition is known as:

Question 11 :
<div><span>Classify the following as physical or chemical change.</span><br/></div><div><span><br/></span></div>Metallic sodium is soft enough to be cut with a knife.<br/>

Question 14 :
Two changes are stated below:<br/>(i) A piece of magnesium gives of bright flames when burnt.<br/>(ii) A piece of iron glows red when heated strongly.<div><span>&#160; &#160; &#160;Which of these is a chemical change?</span></div>

Question 16 :
The change given below is an example of :<br/><div><span>$\text{Hydrogen + Oxygen}$ $\longrightarrow$ $\text {Water}$</span><br/></div>

Question 17 :
Match the columns:<div><br/><table class="wysiwyg-table"><tbody><tr><td></td><td>I</td><td></td><td>II</td></tr><tr><td>(a)</td><td>Physical change</td><td>(i)</td><td>Curdling of milk</td></tr><tr><td>(b)</td><td>Chemical change</td><td>(ii)</td><td>Demagnetisation of magnets</td></tr><tr><td></td><td></td><td>(iii)</td><td>Digestion of food</td></tr><tr><td></td><td></td><td>(iv)</td><td>Crystallisation of substance</td></tr><tr><td></td><td></td><td>(v)</td><td>Rusting of iron</td></tr></tbody></table></div>

Question 24 :
Which of the following BEST describes the differences between particles of solid and particles of liquid?

Question 25 :
When magnesium ribbon burns in the air, it forms white ash. The chemical name of white ash is:

Question 32 :
Which of the following is the most common solvent used for crystallization?

Question 33 :
Anaerobic bacteria digest animal waste and produce biogas(Process-A). The biogas is then burnt as fuel(Process-B). The following statements pertain to these changes. Choose the correct one.

Question 36 :
Dissolution of common salt or sugar in water is an example of:

Question 44 :
$H_{2}O_{(l)}\rightleftharpoons H_{2}O_{(g)}$<br>What type of change is represented by the equation above?

Question 46 :
Which of the following is an example of a physical change?

Question 50 :
Which of the following is a physical change?<br/>a) Hammering of a red hot iron rod to make a flat sheet.<br/>b) Formation of ice by cooling of water.<br/>c) Rising of water vapors from sea to make clouds.<br/>d) Heating of charcoal in the air to high temperature till it begins to flow.

Question 52 :
To prevent rusting, the underside of the ships is coated with:

Question 54 :
The process in which substances undergo change to produce new substances with new properties are-

Question 60 :
<div><span>Identify the chemical changes in the list:</span></div><div>(i) Ripening of fruits</div><div>(ii) Fermentation of grapes</div><div>(iii) Magnetization of iron</div>

Question 61 :
<span>Why is zinc better than tin if we want to protect a piece of iron from rusting by electroplating?</span>

Question 64 :
In a pressure-kerosene stove,<br>(i) We pump kerosene and convert it into vapours.<br>(ii) The vapours are then ignited.<br>Which of the following is true about the above statements?