Chapter 3. Metals and Non-metals 3.5. Corrosion You have learnt the following about corrosion in Chapter 1 –Silver articles become black after some time when exposed to air. This is because it reacts with sulphur in the air to form a coating of silver sulphide. Copper reacts with moist carbon dioxide in the air and […]
Occurrence Of Metals
Chapter 3. Metals and Non-metals 3.4. Occurrence Of Metals The earth’s crust is the major source of metals. Seawater also contains some soluble salts such as sodium chloride, magnesium chloride, etc.The elements or compounds, which occur naturally in the earth’s crust, are known as minerals. At some places, minerals contain a very high percentage of […]
How Do Metals And Non-Metals React?
Chapter 3. Metals and Non-metals 3.3. How Do Metals And Non-Metals React? In the above activities, you saw the reactions of metals with a number of reagents. Why do metals react in this manner? Let us recall what we learnt about the electronic configuration of elements in Class IX. We learnt that noble gases, which […]
Chemical Properties Of Metals
Chapter 3. Metals and Non-metals 3.2. Chemical Properties Of Metals We will learn about the chemical properties of metals in the following Sections 3.2.1 to 3.2.4. For this, collect the samples of following metals – aluminium, copper, iron, lead, magnesium, zinc and sodium. 3.2.1. What happens when Metals are burnt in Air? You have seen […]
Chapter 3. Metals and Non-metals In Class IX you have lear that elements can be classified as metals or non-metals on the basis of nt about various elements. You have seen their properties. Think of some uses of metals and non-metals in your daily life. What properties did you think of while categorising elements as […]
Chapter 2. Acids Bases and Salt – Exercises
Chapter 2. Acids Bases and Salt 2.5. Exercises – Group Actitvity A. Exercises 1. A solution turns red litmus blue, its pH is likely to be(a) 1 (b) 4 (c) 5 (d) 10 2. A solution reacts with crushed egg-shells to give a gas that turns lime-water milky. The solution contains(a) NaCl (b) HCl (c) […]
More About Salts
Chapter 2. Acids Bases and Salt 2.4. More About Salts In the previous sections we have seen the formation of salts during various reactions. Let us understand more about their preparation, properties and uses. Activity 2.13 Write the chemical formulae of the salts given below. Potassium sulphate, sodium sulphate, calcium sulphate,magnesium sulphate, copper sulphate, sodium […]
How Strong Are Acid Or Base Solutions?
Chapter 2. Acids Bases and Salt 2.3. How Strong Are Acid Or Base Solutions? We know how acid-base indicators can be used to distinguish between an acid and a base. We have also learnt in the previous section about dilution and decrease in concentration of H+ or OH– ions in solutions. Can we quantitatively find […]
What Do All Acids And All Bases Have In Common?
Chapter 2. Acids Bases and Salt 2.2. What Do All Acids And All Bases Have In Common? In Section 2.1 we have seen that all acids have similar chemical properties. What leads to this similarity in properties? We saw in Activity 2.3 that all acids generate hydrogen gas on reacting with metals, so hydrogen seems […]
Understanding The Chemical Properties Of Acids And Bases
Chapter 2. Acids Bases and Salt You have lear tastes of food are due to acids and bases, respectively, present in them. nt in your previous classes that the sour and bitterIf someone in the family is suffering from a problem of acidity after overeating, which of the following would you suggest as a remedy– […]
Chapter 1. Chemical Reactions and Equations – Exercises
Chapter 1. Chemical Reactions and Equations 1.4. Exercises and Group Activity A. Exercises 1. Which of the statements about the reaction below are incorrect? 2PbO(s) + C(s) → 2Pb(s) + CO2(g) (a) Lead is getting reduced. (b) Carbon dioxide is getting oxidised. (c) Carbon is getting oxidised. (d) Lead oxide is getting reduced. (i) (a) […]
Have You Observed The Effects Of Oxidation Reactions In Everyday Life?
Chapter 1. Chemical Reactions and Equations 1.3. Have You Observed The Effects Of Oxidation Reactions In Everyday Life? 1.3.1. Corrosion You must have observed that iron articles are shiny when new, but get coated with a reddish brown powder when left for some time. This process is commonly known as rusting of iron. Some other […]
Types Of Chemical Reactions
Chapter 1. Chemical Reactions and Equations 1.2. Types Of Chemical Reactions We have learnt in Class IX that during a chemical reaction atoms of one element do not change into those of another element. Nor do atoms disappear from the mixture or appear from elsewhere. Actually, chemical reactions involve the breaking and making of bonds […]
Chapter 1. Chemical Reactions and Equations Consider the following situations of daily life and think what happens when – milk is left at room temperature during summers. an iron tawa/pan/nail is left exposed to humid atmosphere. grapes get fermented. food is cooked. food gets digested in our body. we respire. In all the above situations, […]