What is the difference between a physical change and a chemical change? List some examples of each.
Solution 17E: Matter is generally classified according to (i) physical state (ii) By using its composition Homogeneous matter is uniform and continuous whereas heterogeneous consist of two or more phase having non-uniformity and discontinuity. Pure substance refers to the matter which has distinct set of properties that are common to all other samples to that substance. A mixture consists of two or more substance which has a wide range of properties are depending on the relative amounts of the components present in the mixture. From the question, According to question, Carbon is burnt in excess of air forms another type of substance .ie usually Carbon dioxide (CO 2 Thus, it is mentioned in the question that the gas formed by A in absence of air has almost the same properties of that gas which is formed by using Carbon in presence of excess oxygen. Therefore Gas C would be carbon dioxide (CO ). 2 Thus, carbon dioxide (CO ) is 2pure substance which contain only two different atoms. That is way Gas C is a compound. On the other hand, gas C formed when substance A is burnt in absence of air which indicated that substance A should contain at least carbon or oxygen. Therefore, A is also a compound having two different atoms. But we can not identified substance C, because nothing is mentioned in the question B.