science cafe

  PART A                                                                                               1 MARK QUESTIONS   Q1. Which of the following gas is used in the storage of fat and oil containing foods for a long time? a)     Carbon dioxide b)     Oxygen c)     Nitrogen d)     Neon Q2.Name the gas evolved when zinc reacts with dil. HCl. Q3. Represent decomposition of ferrous sulphate with the help of balanced chemical equation. Q4. X + Y ...

Any change can be classified as physical change and chemical change. Physical changes can be easily reversed but, it is not easy to reverse a chemical change.In chemical changes, new substances are formed and it is difficult to regenerate the original substances. Chemical changes are more permanent than physical changes.Chemical reaction involves chemical changes.Chemical reactions are the processes in which new substances with new properties are formed.During a chemical reaction, atoms of one element do not change into those of another element. Only a rearrangement of atoms takes place in a chemical reaction. Magnesium ribbon burns with a dazzling white flame and changes into a white powder. This powder is magnesium oxide. It is formed due to the reaction between magnesium and oxygen present in the air. Magnesium + Oxygen =Magnesium Oxide REACTANTS AND PRODUCTS The substances which take part in a chemical reaction are called reactants.The new substances produced as a result of...