p.18
Alloys and Their Properties
What is solder used for?
Welding electrical wires together.
p.5
Chemical Properties of Metals
What happens when metals are burnt in air?
Almost all metals combine with oxygen to form metal oxides.
p.6
Corrosion and Prevention
What is the significance of the oxide layer formed on metals?
It protects the metal from further oxidation.
p.17
Extraction of Metals from Ores
Define the term 'Gangue'.
The worthless material that surrounds or is mixed with the valuable mineral in an ore.
p.11
Ionic Compounds and Their Characteristics
Does sodium chloride (NaCl) exist as molecules?
No, it exists as aggregates of oppositely charged ions.
p.9
Reactivity Series of Metals
What can reactive metals do in relation to less reactive metals?
Reactive metals can displace less reactive metals from their compounds in solution or molten form.
p.1
Physical Properties of Metals
What happens when you cut metals like iron, copper, and aluminum?
They can be cut with a sharp knife, indicating their malleability.
p.8
Chemical Properties of Metals
What was observed regarding the rate of bubble formation in the activity?
Magnesium produced bubbles the fastest.
p.5
Chemical Properties of Metals
What is the reaction equation for copper burning in air?
2Cu + O2 → 2CuO (Copper + Oxygen → Copper(II) oxide)
p.6
Reactivity Series of Metals
Why are potassium and sodium kept immersed in kerosene oil?
To protect them and prevent accidental fires due to their vigorous reaction with oxygen.
p.6
Corrosion and Prevention
What happens to the surfaces of metals like magnesium, aluminium, and zinc at ordinary temperatures?
They are covered with a thin layer of oxide that prevents further oxidation.
p.17
Extraction of Metals from Ores
Define the term 'Ore'.
A type of rock that contains sufficient minerals with important elements including metals that can be extracted for economic gain.
p.9
Reactivity Series of Metals
What is the position of potassium in the reactivity series?
Potassium is the most reactive metal.
p.3
Classification of Elements
What is a notable exception regarding the physical state of metals at room temperature?
All metals except mercury exist as solids.
p.1
Classification of Elements
How can elements be classified?
As metals or non-metals based on their properties.
p.3
Physical Properties of Metals
Why are school bells made of metals?
Because metals are sonorous and produce sound when struck.
p.1
Chemical Properties of Metals
What should you be cautious about when handling sodium metal?
Always handle sodium metal with care due to its reactivity.
p.3
Physical Properties of Non-metals
What states of matter do non-metals exist in?
Non-metals can be solids or gases, except bromine which is a liquid.
p.13
Ionic Compounds and Their Characteristics
In which solvents are ionic compounds generally soluble?
Ionic compounds are generally soluble in water but insoluble in solvents like kerosene and petrol.
p.10
Chemical Properties of Metals
What is the reaction of iron with steam?
3Fe + 4H2O → Fe3O4 + 4H2.
p.9
Reactivity Series of Metals
Which metal is the least reactive according to the activity series?
Gold is the least reactive metal.
p.8
Chemical Properties of Metals
What happens when copper wire is placed in iron sulfate solution?
No reaction occurs; copper does not displace iron.
p.19
Alloys and Their Properties
What is an alloy?
An alloy is a homogeneous mixture of two or more metals, or a metal and a non-metal.
p.17
Corrosion and Prevention
What happens to iron nails in test tube A?
They rust due to exposure to both air and water.
p.15
Extraction of Metals from Ores
What happens during the roasting of zinc ores?
2ZnS(s) + 3O2(g) → 2ZnO(s) + 2SO2(g).
p.12
Ionic Compounds and Their Characteristics
What are the cation and anion present in MgCl2?
Cation: Magnesium (Mg²⁺); Anion: Chloride (Cl⁻).
p.9
Reactivity Series of Metals
What is the general form of a displacement reaction?
Metal A + Salt solution of B → Salt solution of A + Metal B.
p.9
Reactivity Series of Metals
What is the reactivity series?
A list of metals arranged in the order of their decreasing activities.
p.13
Ionic Compounds and Their Characteristics
How do ionic compounds conduct electricity?
Ionic compounds conduct electricity in solution or molten state due to the movement of ions; they do not conduct electricity in solid state.
p.10
Chemical Properties of Metals
What happens when calcium reacts with water?
Ca + 2H2O → Ca(OH)2 + H2.
p.9
Reactivity Series of Metals
What does the reactivity series help to understand?
It helps to understand the relative reactivities of different metals.
p.2
Physical Properties of Metals
What is the significance of malleability and ductility in metals?
They allow metals to be given different shapes according to our needs.
p.14
Classification of Elements
Which metals are commonly found in the free state?
Gold, silver, platinum, and copper.
p.19
Chemical Properties of Metals
What are amphoteric oxides?
Oxides like aluminium oxide and zinc oxide that show properties of both basic and acidic oxides.
p.15
Extraction of Metals from Ores
What is calcination?
The process of converting carbonate ores into oxides by heating strongly in limited air.
p.11
Ionic Compounds and Their Characteristics
What happens when sodium and chlorine react?
Sodium loses an electron, which is taken up by chlorine.
p.12
Physical Properties of Non-metals
What is the physical state of common ionic compounds like sodium chloride?
They are typically solid at room temperature.
p.13
Ionic Compounds and Their Characteristics
Why do ionic compounds have high melting and boiling points?
Because a considerable amount of energy is required to break the strong inter-ionic attraction.
p.10
Chemical Properties of Metals
Why is sodium kept immersed in kerosene oil?
To prevent it from reacting with moisture and oxygen in the air.
p.11
Ionic Compounds and Their Characteristics
What type of bond forms between sodium and chloride ions?
Strong electrostatic forces of attraction.
p.7
Chemical Properties of Metals
What do metals produce when they react with water?
A metal oxide and hydrogen gas.
p.12
Physical Properties of Non-metals
What are the melting and boiling points of MgCl2?
Melting point: 981 K; Boiling point: 1685 K.
p.6
Corrosion and Prevention
What happens during the anodising process?
A clean aluminium article is made the anode and electrolysed with dilute sulphuric acid to form a thicker protective oxide layer.
p.17
Corrosion and Prevention
What conditions are necessary for iron to rust?
Presence of both air and water.
p.15
Extraction of Metals from Ores
What is cinnabar and how is it processed to obtain mercury?
Cinnabar (HgS) is an ore of mercury that is heated to form mercuric oxide (HgO), which is then reduced to mercury.
p.5
Chemical Properties of Metals
What alkalis are formed when sodium oxide and potassium oxide dissolve in water?
Sodium hydroxide (NaOH) and potassium hydroxide (KOH).
p.15
Extraction of Metals from Ores
What is roasting in the context of metal extraction?
The process of converting metal sulphides into oxides by heating strongly in the presence of excess air.
p.11
Ionic Compounds and Their Characteristics
What charge does a chlorine atom acquire after gaining an electron?
A unit negative charge, forming a chloride anion (Cl⁻).
p.17
Extraction of Metals from Ores
Define the term 'Mineral'.
A naturally occurring substance that is solid and stable at room temperature, represented by a chemical formula.
p.1
Classification of Elements
What metals are suggested for the activities?
Iron, copper, aluminum, magnesium, sodium, lead, and zinc.
p.12
Ionic Compounds and Their Characteristics
What can be inferred about the nature of ionic compounds based on conductivity tests?
Ionic compounds conduct electricity when dissolved in water.
p.20
Reactivity Series of Metals
Which pair will give a displacement reaction: NaCl solution and copper metal?
No, it will not give a displacement reaction.
p.5
Chemical Properties of Metals
What happens to most metal oxides in water?
Most metal oxides are insoluble in water, but some dissolve to form alkalis.
p.6
Reactivity Series of Metals
What should be done to determine the reactivity of metals with water?
Put small pieces of metals in beakers with cold water and hot water, and observe their reactions.
p.17
Corrosion and Prevention
Why do iron nails not rust in test tube B?
Because there is no air dissolved in the boiled distilled water.
p.21
Chemical Properties of Metals
What is the action of gas evolved from heated sulphur powder on dry litmus paper?
It does not change color.
p.14
Reactivity Series of Metals
Why are many metal ores oxides?
Because oxygen is a very reactive and abundant element on Earth.
p.13
Ionic Compounds and Their Characteristics
What is the physical nature of ionic compounds?
Ionic compounds are solids, somewhat hard, and brittle due to strong forces of attraction between positive and negative ions.
p.20
Chemical Properties of Metals
How do non-metals form negatively charged ions?
By gaining electrons when reacting with metals.
p.16
Chemical Properties of Metals
What happens when manganese dioxide is heated with aluminium powder?
It produces manganese, aluminium oxide, and heat.
p.4
Physical Properties of Non-metals
What property of graphite allows it to conduct electricity?
It has a structure that allows free movement of electrons.
p.8
Chemical Properties of Metals
What is aqua regia and what can it dissolve?
A mixture of concentrated hydrochloric acid and nitric acid that can dissolve gold and platinum.
p.5
Chemical Properties of Metals
What are amphoteric oxides?
Metal oxides that react with both acids and bases to produce salts and water.
p.19
Physical Properties of Metals
What are the characteristics of metals?
Metals are lustrous, malleable, ductile, and good conductors of heat and electricity. They are solids at room temperature, except mercury which is a liquid.
p.7
Chemical Properties of Metals
What occurs during the reaction of sodium with water?
The evolved hydrogen immediately catches fire due to the violent exothermic reaction.
p.13
Reactivity Series of Metals
How does the reactivity series of metals relate to metal extraction?
The reactivity series helps in understanding how a metal is extracted from its ore, with less reactive metals often found in a free state.
p.21
Chemical Properties of Metals
Why are platinum, gold, and silver used to make jewellery?
They are non-reactive and do not tarnish easily.
p.18
Alloys and Their Properties
How does the electrical conductivity of an alloy compare to that of pure metals?
The electrical conductivity and melting point of an alloy is less than that of pure metals.
p.9
Reactivity Series of Metals
What is the basis for determining if a reaction has occurred in a displacement reaction?
If metal A displaces metal B from its solution, it is more reactive than B.
p.16
Reactivity Series of Metals
What is the purpose of displacement reactions in metallurgy?
They can displace metals of lower reactivity from their compounds.
p.16
Extraction of Metals from Ores
What is the thermit reaction used for?
To join railway tracks or cracked machine parts.
p.8
Chemical Properties of Metals
Why does hydrogen gas not evolve when a metal reacts with nitric acid?
Because nitric acid is a strong oxidizing agent that oxidizes H2 to water.
p.13
Extraction of Metals from Ores
What are ores?
Ores are minerals that contain a high percentage of a particular metal and can be profitably extracted.
p.4
Classification of Elements
How can elements be classified as metals and non-metals?
Based on their chemical properties.
p.15
Extraction of Metals from Ores
How can metals low in the activity series be extracted?
By heating their oxides alone.
p.2
Physical Properties of Metals
What do metals generally exhibit in terms of hardness?
Metals are generally hard, but hardness varies from metal to metal.
p.18
Alloys and Their Properties
What does 22 carat gold consist of?
22 parts of pure gold and 2 parts of either copper or silver.
p.3
Applications of Metals and Non-metals
Why are electric wires coated with PVC or rubber-like materials?
To provide insulation and prevent electric shocks.
p.3
Physical Properties of Metals
What happens when metals strike a hard surface?
They produce a sound and are said to be sonorous.
p.1
Physical Properties of Metals
What is metallic lustre?
The shining surface of metals in their pure state.
p.12
Ionic Compounds and Their Characteristics
What are ionic compounds formed by?
The transfer of electrons from a metal to a non-metal.
p.3
Physical Properties of Non-metals
What are some examples of non-metals?
Carbon, sulphur, iodine, oxygen, hydrogen.
p.12
Physical Properties of Non-metals
What happens when ionic compounds are heated?
They may impart color to the flame and can melt.
p.1
Applications of Metals and Non-metals
What is the significance of physical properties in categorizing elements?
Physical properties help in determining the uses of metals and non-metals.
p.9
Reactivity Series of Metals
Which metal is more reactive according to the observations in Activity 3.12, copper or iron?
Iron is more reactive than copper.
p.20
Chemical Properties of Metals
What types of oxides do non-metals form?
Acidic or neutral oxides.
p.12
Ionic Compounds and Their Characteristics
Are ionic compounds soluble in water?
Yes, many ionic compounds are soluble in water.
p.3
Physical Properties of Metals
What indicates that a metal is a good conductor of electricity?
The bulb glows when the metal is placed in an electric circuit.
p.16
Reactivity Series of Metals
Why can't metals high up in the reactivity series be reduced by carbon?
They have more affinity for oxygen than carbon.
p.20
Chemical Properties of Metals
Do non-metals displace hydrogen from dilute acids?
No, they do not displace hydrogen; they react with hydrogen to form hydrides.
p.16
Extraction of Metals from Ores
How are sodium, magnesium, and calcium obtained?
By electrolytic reduction of their molten chlorides.
p.6
Corrosion and Prevention
What is anodising?
A process of forming a thick oxide layer on aluminium to improve its resistance to corrosion.
p.3
Physical Properties of Metals
What general physical properties can be observed for metals and non-metals?
Hardness, malleability, ductility, conductivity, and sonority.
p.15
Extraction of Metals from Ores
What is the basis for separating gangue from ore?
Differences between the physical or chemical properties of the gangue and the ore.
p.20
Corrosion and Prevention
Which method is suitable for preventing an iron frying pan from rusting?
All of the above (applying grease, paint, or a coating of zinc).
p.5
Chemical Properties of Metals
How does aluminium oxide react with hydrochloric acid?
Al2O3 + 6HCl → 2AlCl3 + 3H2O.
p.8
Chemical Properties of Metals
What happens when an iron nail is placed in copper sulfate solution?
Iron displaces copper, resulting in a reaction.
p.13
Extraction of Metals from Ores
What are minerals?
Minerals are elements or compounds that occur naturally in the earth's crust.
p.4
Physical Properties of Metals
What are alkali metals known for in terms of physical properties?
They are soft and can be cut with a knife, have low densities and low melting points.
p.7
Chemical Properties of Metals
What happens to soluble metal oxides when they dissolve in water?
They form metal hydroxide.
p.13
Extraction of Metals from Ores
What is the major source of metals?
The earth's crust is the major source of metals.
p.10
Reactivity Series of Metals
What is the reason metals react to attain a stable electronic configuration?
Metals tend to lose electrons to achieve a completely filled valence shell.
p.7
Chemical Properties of Metals
How does calcium react with water compared to potassium and sodium?
Calcium's reaction is less violent and does not produce enough heat for hydrogen to catch fire.
p.10
Reactivity Series of Metals
What would you observe if metal B is added to a solution of Copper(II) sulphate?
A displacement reaction occurs, resulting in the formation of copper.
p.14
Reactivity Series of Metals
What type of ores are metals in the middle of the activity series mainly found as?
Oxides, sulphides, or carbonates.
p.7
Chemical Properties of Metals
What do metals like lead, copper, silver, and gold do in relation to water?
They do not react with water at all.
p.14
Reactivity Series of Metals
What are the three categories of metals based on reactivity?
Metals of low reactivity, medium reactivity, and high reactivity.
What is the process of electrolytic refining?
The impure metal is made the anode, and pure metal is made the cathode in an electrolyte solution.
p.20
Chemical Properties of Metals
Why are food cans coated with tin and not zinc?
Because zinc is more reactive than tin.
p.19
Corrosion and Prevention
What is corrosion?
The phenomenon where the surface of some metals, such as iron, is corroded when exposed to moist air for a long period of time.
p.21
Extraction of Metals from Ores
In the electrolytic refining of a metal M, what are the anode, cathode, and electrolyte?
Anode: impure metal M, Cathode: pure metal M, Electrolyte: a solution of metal salt.
p.7
Chemical Properties of Metals
Which metals do not react with cold or hot water?
Aluminium, iron, and zinc.
p.15
Extraction of Metals from Ores
How is zinc oxide reduced to metallic zinc?
By heating with carbon: ZnO(s) + C(s) → Zn(s) + CO(g).
p.21
Chemical Properties of Metals
Why is aluminium used to make utensils for cooking despite being highly reactive?
It forms a protective oxide layer that prevents further reaction.
p.14
Classification of Elements
What are the combined states in which copper and silver can be found?
As their sulphide or oxide ores.
p.7
Chemical Properties of Metals
What happens to magnesium when it reacts with hot water?
It forms magnesium hydroxide and hydrogen, and starts floating due to hydrogen bubbles sticking to its surface.
p.17
Corrosion and Prevention
What is rust?
A brown flaky substance formed when iron reacts with moist air.
p.2
Physical Properties of Metals
What observation can be made about metals when heated?
Metals are good conductors of heat and have high melting points.
p.6
Reactivity Series of Metals
What is the outcome of metals reacting with steam?
Some metals may react with steam while others do not.
p.19
Reactivity Series of Metals
What is the activity series?
A list of common metals arranged in order of their decreasing reactivity.
p.19
Chemical Properties of Metals
What happens in a displacement reaction?
A more reactive metal displaces a less reactive metal from its salt solution.
p.21
Chemical Properties of Metals
What type of solution did the man use to clean the gold bangles?
A strong acid, likely hydrochloric acid, which can dissolve impurities but also gold.
p.19
Extraction of Metals from Ores
What is metallurgy?
The extraction of metals from their ores and then refining them for use.
p.15
Extraction of Metals from Ores
What is the chemical reaction for obtaining mercury from cinnabar?
2HgS(s) + 3O2(g) → 2HgO(s) + 2SO2(g) followed by 2HgO(s) → 2Hg(l) + O2(g).
p.20
Ionic Compounds and Their Characteristics
What are amphoteric oxides?
Oxides that can react with both acids and bases.
p.21
Chemical Properties of Metals
What is the action of gas evolved from heated sulphur powder on moist litmus paper?
It turns red, indicating acidity.
p.15
Extraction of Metals from Ores
What is the chemical reaction for the calcination of zinc carbonate?
ZnCO3(s) → ZnO(s) + CO2(g).
p.21
Chemical Properties of Metals
Why are sodium, potassium, and lithium stored under oil?
To prevent them from reacting with moisture and oxygen in the air.
p.18
Corrosion and Prevention
What is galvanisation?
A method of protecting steel and iron from rusting by coating them with a thin layer of zinc.
p.18
Alloys and Their Properties
What happens to iron when mixed with a small amount of carbon?
It becomes hard and strong.
p.18
Alloys and Their Properties
What is an alloy?
A homogeneous mixture of two or more metals, or a metal and a non-metal.
p.10
Reactivity Series of Metals
Which metal is the most reactive among A, B, C, and D?
Metal B (based on the displacement reactions).
p.17
Corrosion and Prevention
Why do iron nails not rust in test tube C?
Because the air is dry, preventing moisture.
p.19
Reactivity Series of Metals
Which metals can displace hydrogen from dilute acids?
Metals above hydrogen in the Activity series.
p.14
Extraction of Metals from Ores
What is the first step in the extraction of metals from ores?
Enrichment of ores by removing impurities called gangue.
p.21
Corrosion and Prevention
Why are sour substances like lemon or tamarind juice effective in cleaning tarnished copper vessels?
They contain acids that react with the tarnish (copper oxide) to remove it.
p.18
Corrosion and Prevention
How can the rusting of iron be prevented?
By painting, oiling, greasing, galvanising, chrome plating, anodising, or making alloys.
p.21
Corrosion and Prevention
What are two ways to prevent the rusting of iron?
1. Applying paint or oil. 2. Galvanization (coating with zinc).
p.21
Extraction of Metals from Ores
Why are carbonate and sulphide ores converted into oxides during extraction?
Oxides are easier to reduce to obtain the metal.
p.18
Alloys and Their Properties
What are brass and bronze examples of?
Brass is an alloy of copper and zinc, and bronze is an alloy of copper and tin.
p.18
Alloys and Their Properties
What is the significance of the iron pillar at Delhi?
It was built over 1600 years ago and is known for its rust resistance.
p.10
Reactivity Series of Metals
What would you observe when zinc is added to a solution of iron(II) sulphate?
A displacement reaction occurs, resulting in the formation of zinc sulfate and iron.
p.19
Physical Properties of Non-metals
What are the properties of non-metals?
Non-metals are neither malleable nor ductile and are bad conductors of heat and electricity, except for graphite.
p.18
Alloys and Their Properties
What is an amalgam?
An alloy where one of the metals is mercury.
p.14
Extraction of Metals from Ores
What is the purpose of removing gangue from ores?
To extract pure metal from the ore.
p.21
Classification of Elements
Differentiate between metals and non-metals based on their chemical properties.
Metals tend to lose electrons and form cations, while non-metals tend to gain electrons and form anions.
p.21
Physical Properties of Metals
Why is copper used to make hot water tanks instead of steel?
Copper has better thermal conductivity and is less prone to corrosion than steel.
p.18
Alloys and Their Properties
What is stainless steel made from?
Iron mixed with nickel and chromium.
