AP 10th Class Physical Science 3rd Lesson Questions and Answers Metals and Non-metals

AP State Board new syllabus AP Board Solutions Class 10 Physics 3rd Lesson Metals and Non-metals Questions and Answers.

10th Class Physical Science 3rd Lesson Metals and Non-metals Questions and Answers

10th Class Physics 3rd Lesson Questions and Answers (Exercise)

Question 1.
Which of the following pairs will give displacement reactions ?
a) NaCl solution and copper metal
b) MgCl₂ solution and aluminium metal
c) FeSO₄ solution and silver metal
d) AgNO₃ solution and copper metal
Answer:
d) AgNO₃ solution and copper metal.

Question 2.
Which of the following methods is suitable for preventing an iron frying pan from rusting ?
a) Applying grease
b) Applying paint
c) Applying a coating of zinc
d) All of the above
Answer:
d) All of the above

Question 3.
An element reacts with oxygen to give a compound with a high melting point. This compound is also soluble in water. The element is likely to be
a) calcium
b) carbon
c) silicon
d) iron.
Answer:
a) calcium

Question 4.
Food cans are coated with tin and not with zinc because
a) zinc is costlier than tin.
b) zinc has a higher melting point than tin.
c) zinc is more reactive than tin.
d) zinc is less reactive than tin.
Answer:
c) zinc is more reactive than tin.

Question 5.
You are given a hammer, a battery, a bulb, wires and a switch.
a) How could you use them to distinguish between samples of metals and non-metals?
b) Assess the usefulness of these tests in distinguishing between metals and non-metals.
Answer:
a) i) Metals can be spread into sheets with the help of hammer while non-metals give powder.
ii) When metals are connected into circuit using battery, bulb, wires and a switch current passes through the circuit and the bulb glows.

b) Hammer is a reliable method because no non-metal can be spread into sheet.

Question 6.
What are amphoteric oxides? Give two examples of amphoteric oxides.
Answer:
Such oxides with react, both with acids as well as bases, to form salts and water, are known as amphoteric oxides. For example, aluminium oxides and zinc oxides.
ZnO + 2HCl → ZnCl₂ + H₂O
ZnO + 2NaOH → Na₂ZnO₂ + H₂O

Question 7.
Name two metals which will displace hydrogen from dilute acids and two metals which will not.
Answer:

1. Metals like sodium and magnesium displace hydrogen from dilute acids (metals) above hydrogen in the activity series.
2. Metals below hydrogen in the activity series like copper and silver do not displace hydrogen from dilute acids.

Question 8.
In the electrolytic refining of a metal M, what would you take as the anode, the cathode and the electrolyte ?
Answer:
Cathode : Pure metal
Anode : Impure metal
Electrolyte : Metal Salt solution

Question 9.
Pratyush took sulphur powder on a spatula and heated it. He collected the gas evolved by inverting a test tube over it, as shown in the figure below.
a) What will be the action of gas on
i) Dry litmus paper.
ii) moist litmus paper.
b) Write a balanced chemical equation for the reaction taking place.

Answer:
a) i) Dry litmus paper – No action
ii) Moist litmus paper – becomes red.

Question 10.
State two ways to prevent the rusting of iron.
Answer:
A. Ways to prevent the rusting of iron
a) By painting
b) By galvanising

Question 11.
What type of oxides are formed when non-metals combine with oxygen ?
Answer:
Acidic oxides

Question 12.
Give reasons :
a) Platinum, gold and silver are used to make jewellery.
b) Sodium, potassium and lithium are stored under oil.
c) Aluminium is a highly reactive metal, yet it is used to make utensils for cooking.
d) Carbonate and sulphide ores are usually converted into oxides during the process of extraction.
Answer:
a) Platinum, gold and silver are non-reactive and give shining surface.
b) Sodium, potassium and lithium are very reactive and catch fire when exposed to air.
c) Aluminium forms a non-reactive layer of aluminium oxide an its surface.
d) It is easier to reduce oxides into metal.

Question 13.
You must have seen tarnished copper vessels being cleaned with lemon or tamarind juice. Explain why these sour substances are effective in cleaning the vessels.
Answer:
Copper vessels get a green deposit of basic copper carbonate. Since copper carbonate dissolves in mild acids of lemon or tamarind juice, copper vessels are cleaned.

Question 14.
Differentiate between metal and non-metal on the basis of their chemical properties.
Answer:

Metals	Non-metals
1) Metals form basic oxides, some of which form alkalis.	1) Non-metals form acidic or neutral oxides.
2) Metals replace hydrogen from acids and form salts.	2) Non-metals donot replace hydrogen from acids.
3) Metals can lose electrons easily to form positive ions.	3) Non-metals can gain electrons easily to form negative ions.
4) With chlorine, metals form chlorides which are covalent.	4) With chlorine, non metals form chlorides which are covalent.
5) With hydrogen, few metals form hydrides which are electrovalent.	5) With hydrogen, non-metals form many stable hydrides which are covalent.
6) Reactive metals can displace hydrogen from water.	6) Non-metals cannot displace hydrogen form water.

Question 15.
A man went door to door posing as a Goldsmith. He promised to bring back the glitter of old and dull gold ornaments. An unsuspecting lady gave a set of gold bangles to him, which he dipped in a particular solution. The bangles sparkled like new but their weight was reduced drastically. The lady was upset but after a futile argument the man beat a hasty retreat. Can you play the detective to find out the nature of the solution he had used ?
Answer:
Aqua regia – a mixture of concentrated hydrochloric acid and concentrated nitric acid in the ratio of 3:1, since it dissolves gold.

Question 16.
Give reasons why copper is used to make hot water tanks and not steel (an alloy of iron).
Answer:
Copper is better conductor of heat than steel, therefore it is used for making hot water tanks.

10th Class PS 2nd Lesson Questions and Answers (InText)

Question 1.
Give an example of a metal which
i) is a liquid at room temperature.
ii) can be easily cut with a knife.
iii) is the best conductor of heat.
iv) is a poor conductor of heat,
Answer:
i) Mercury
ii) Sodium
iii) Silver
iv) Lead

Question 2.
Explain the meanings of malleable and ductile.
Answer:
Malleable is the property by which metals can be beaten into sheets with hammering without returning to previous condition.
Ductile is the ability of metals to be drawn into thin wires.

Page No. 96

Question 3.
Why is sodium kept immersed in kerosene oil ?
Answer:
a) Sodium is very reactive. If kept exposed to air it catches fire.
b) If sodium is kept in water, it reacts rapidly with water.

Question 4.
Write equations for the reactions of
i) iron with steam
ii) calcium and potassium with water
Answer:

Question 5.
Samples of four metals A, B, C and D were taken and added to the following solution one by one. The results obtained have been tabulated as follows.

Metal	Iron (II) sulphate	Copper (II) sulphate	Zinc sulphate	Silver sulphate
A	No reaction	Displacement
B	Displacement		No reaction
C	No reaction	No reaction	No reaction	Displacement
D	No reaction	No reaction	No reaction	No reaction

Use the Table above to answer the following questions about metals A, B, C and D.
i) Which is the most reactive metal ?
ii) What would you observe if B is added to a solution of Copper(II) sulphate ?
iii) Arrange the metals A, B, C and D in the order of decreasing reactivity.
Answer:
i) B is most reactive metal.
ii) If B is added to a solution of copper (II) sulphate, then it would displace copper
B + CuSO₄ → Displacement
iii) The arrangement of the metals in the order of decreasing reactivity is B > A > C > D

Question 6.
Which gas is produced when dilute hydrochloric acid is added to a reactive metal? Write the chemical reaction when iron reacts with dilute H₂SO₄.
Answer:
When dilute hydrochloric acid is added to a reactive metal, hydrogen gas is evolved The reaction between iron and H₂SO₄ is
Fe(s) + H₂SO_4(dil) → FeSO_4(aq) + H_2(g)

Question 7.
What would you observe when zinc is added to a solution of iron(II) sulphate ? Write the chemical reaction that takes place.
Answer:
Zinc is more reactive than iron. Therefore, if zinc is added to a solution of iron (II) sulphate, then it would displace iron from the solution
Zn_(s) + FeSO_4(aq) → ZnSO_4(aq) + Fe_(s)

Page No. 102

Question 8.
i) Write the electron-dot structures for sodium, oxygen and magnesium.
ii) Show the formation of Na₂O and MgO by the transfer of electrons.
iii) What are the ions present in these compounds ?
Answer:

iii) In Na₂O, ions present are Na⁺ and O^-2.
In MgO, ions present are Mg⁺² and O^-2.

Question 9.
Why do ionic compounds have high melting points ?
Answer:
Ionic compounds have high melting points because of the strong force of attraction between the oppositely charged ions. High energy is required to break the metallic bonds between these ions.

Page No. 108

Question 10.
Define the following terms.
i) Mineral
ii) Ore
iii) Gangue
Answer:
i) Mineral: The elements and compounds which occur naturally in the earth’s crust are known as minerals.
ii) Ore : The minerals which contain a high percentage of the metal, i.e., the mineral from which a metal can be profitably extracted is called an ore.
iii) Gangue : Ores mined from the earth are usually contaminated with large amounts of impurities like sand, soil, mud etc. These impurities are called gangue.

Question 11.
Name two metals which are found in nature in the free state.
Answer:
Gold and Platinum.

Question 12.
What chemical process is used for obtaining a metal from its oxide ?
Answer:
The chemical process used for obtaining a metal from its oxide is reduction
There are mainly three different methods of reduction
i) By heating
ii) By using carbon
iii) By using aluminium, calcium, sodium etc …….. as reducing agents.

Page No. 112

Question 13.
Metallic oxides of zinc, magnesium and copper were heated with the following metals.

Metal	Zinc	Magnesium	Copper
Zinc oxide
Magnesium oxide
Copper oxide

In which cases will you find displacement reactions taking place ?
Answer:

Metal	Zinc	Magnesium	Copper
Zinc oxide	No	Yes	No
Magnesium oxide	No	No	No
Copper oxide	Yes	Yes	No

Question 14.
Which metals do not corrode easily ?
Answer:
Gold and Platinum.

Question 15.
What are alloys ?
Answer:
Alloys are a homogeneous mixture of two or more metals or a metal and a non-metal. For example, brass is an alloy of copper and zinc.

AP 10th Class Physical Science Chapter 3 Questions and Answers (Lab Activities)

Activity – 3.1 (Page. No. 80)

Question 1.
How do you observe the lustre in metals ?
Answer:

1. Take samples of iron, copper, aluminium and magnesium. Note the appearance of each sample – Surfaces appear dull.
2. Clean the surface of each sample by rubbing them with sand paper and note their appearance again – Surfaces shine. Pure metals have shining surface. This property is called metallic lustre.

Activity – 3.2 (Page. No. 80)

Question 2.
How do you check for the hardness of metals ?
Answer:

1. Take small pieces of iron, copper, aluminium and magnesium. Try to cut these metals with a sharp knife and note your observations.
2. Pieces of iron, copper, aluminium are hard and difficult to cut with a knife. How ever magnesium can be cut.
3. Hold a piece of sodium metal with a pair of tongs.
   Caution: Always handle sodium metal with care. Dry it by pressing between the folds of a filter paper.
4. Put it on a watch-glass and try to cut it with a knife.
   What do you observe ?
5. Sodium can be cut easily with a knife.

Activity – 3.3 (Page. No. 80)

Question 3.
How do you check for the malleability of metals ?
Answer:

1. Take pieces of iron, zinc, lead and copper.
   Take any one metal on a block of iron and strike it four or five times with a hammer. What do you observe ?
2. The metal gets flattend.
3. Repeat with other metals.
4. Record the change in the shape of these metals.
   Pieces of iron, zinc, lead and copper get changed into sheets when struck with a hammer.

Activity – 3.4 (Page. No. 80)

Question 4.
List the metals whose wires you have seen in daily life.
Answer:

1. Copper : Copper wires are widely used for electrical wiring in homes, buildings and electronics.
2. Aluminium : Aluminium wires are also used for electrical transmission and distribution.
3. Steel : Steel wires are commonly used in construction, fencing and as structural components.
4. Iron : Iron wires are used in various industrial applications and for making wire mesh and fencing.
5. Nickel : Nickel wires are used in heating elements.
6. Gold : Gold wires are used in jewellery making.
7. Silver : Silver wires are used in electrical contacts, circuitry and in jewellery making.

Activity – 3.5 (Page. No. 82)

Question 5.
Write an activity that shows metals are good conductors of heat.
Answer:
Aim : To show that metals are good conductors of heat and have high melting point.
Materials required : Clamp stand, burner, wax, pin, aluminium or copper wire

Procedure :

1. Take an aluminium or copper wire. Clamp this wire on a stand, as shown in Figure.
2. Fix a pin to the free end of wire using wax.
3. Heat the wire with a spirit lamp, candle or a burner near the place where it is clamped.

Observation : On heating aluminium or copper wire, at one end, soon the heat reaches the other end, melts wax and the pin gets detached. This shows aluminium and copper are good conductors of heat. The metal wires do not melt easily.
Conclusion : Metals are good conductors of heat and have high melting point.

Activity – 3.6 (Page. No. 82)

Question 6.
Write an activity that shows metals are good conductors of electricity.
Answer:
Aim : To show that metals are good conductors of electricity.
Materials required : Battery, bulb, switch, connecting wires with clips, metals (Fe, Zn, Al, etc.,)

Procedure :

1. Set up an electric circuit as shown in Figure.
2. Place the metal to be tested in the circuit between terminals A and B as shown..
3. Observe whether bulb glows or not. Record your observations.

Observation : The bulb glows.
Conclusion : Metals are good conductors of electricity

Activity – 3.7 (Page. No. 84)

Question 7.
Write an activity to demonstrate different properties of non-metals,
Answer:

1. Collect samples of carbon (coal or graphite), sulphur and iodine.
2. Carry out the Activities to test for lustre, hardness, malleability, ductility, sonority and conduction of electricity with these non-metals and record your observations. Compile your observations regarding metals and non-metals in Table.

Activity – 3.8 (Page. No. 84)

Question 8.
Write an activity to demonstrate the nature of metal and non-metal oxides.
Answer:

1. Take a magnesium ribbon and some sulphur powder.
2. Burn the magnesium ribbon. Collect the ashes formed and dissolve them in water.
3. Test the resultant solution with both red and blue litmus paper.
4. Is the product formed on burning magnesium acidic or basic ?
   The solution of product (magnesium oxide) of burning magnesium ribbons turns red litmus blue. So magnesium oxide is basic.
5. Now burn sulphur powder. Place a test tube over the burning sulphur to collect the fumes produced.
6. Add some water to the above test tube and shake.
7. Test this solution with blue and red litmus paper.
   Is the product formed on burning sulphur acidic or basic ?
8. The burning of sulphur powder gives SO₂ which in solution turns blue litmus red.
   So SO₂ is acidic.
   Can you write equations for these reactions?
   i) 2Mg_(s) + O_2(g) → 2MgO_(s)
   ii) S_(s) + O_2(g) → SO_2(g)

Activity – 3.9 (Page. No. 86)

Question 9.
What happens when Metals are burnt in the All? Explain with an activity.
Answer:
CAUTION : It would be better if students wear eye protection.

1. Hold any of the samples taken above with a pair of tongs and try burning over a flame.
2. Repeat with the other metal samples.
3. Collect the product if formed.
4. Let the products and the metal surface cool down.
5. Now observe for…
   • Which metals burn easily ?
   • What flame colour did you observe when the metal burnt ?
   • How does the metal surface appear after burning ?
   • Arrange the metals in the decreasing order of their reactivity towards oxygen.
   • Are the products soluble in water.
6. 
7. Almost all metals combine with oxygen to form metal oxides.
8. Metal + Oxygen → Metal oxide

Activity – 3.10 (Page. No. 90)

Question 10.
What happens when metals react with water ? Explain with an activity.
Answer:

1. Collect the samples of the metals like aluminium, iron, zinc, potassium, sodium, calcium, magnesium, etc.
2. Put small pieces of the samples separately in beakers half-filled with cold water.
   Which metals reacted with cold water ? Arrange them in the increasing order of their reactivity with cold water.
3. Potassium reacted with cold water. The reactivity of metals with cold water increases in the order.
   Mg < Ca < Na < K
   Did any metal produce fire in water ?
4. Sodium and potassium catch fire on water.
   Does any metal start floating after some time.
5. Calcium starts floating after some time.
6. Put the metals that did not react with cold water in beakers half – filled with hot water.
7. For the metals that did not react with hot water, arrange the apparatus as shown in figure and observe their reaction with steam.
   
   Which metal did not react even with steam ?
8. Metals like copper, silver and gold did not react even with steam.
   Arrange the metals in the decreasing order of reactivity with water.
9. Metals such as lead, copper, silver and gold do not react with water at all the overall . reactivity of metals with water decreases in the order.
   K > Na > Ca > Mg > A/ > Zn > Fe

Activity – 3.11 (Page. No. 92)

Question 11.
What happens when Metals react with water ? Explain with an activity.
Answer:

1. Collect all the metal samples except sodium and potassium again. If the samples are tarnished, rub them clean with sand paper.
2. Put the samples separately in test tubes containing dilute hydrochloric acid.
3. Suspend thermometers in the test tubes, so that their bulbs are dipped in the acid.
   Observe the rate of formation of bubbles carefully.
4. The rate of formation of bubbles is fastest in case of magnesium.
   Which metals reacted vigorously with dilute hydrochloric acid ?
5. Metals like Mg, Al, Zn and Fe react vigorously with dilute hydrochloric acid.
   With which metal did you record the highest temperature ?
6. Mg
   Arrange the metals in the decreasing order of reactivity with dilute acids.
7. The reactivity of metals Mg, Zn, Al and Fe with dilute hydrochloric acid decreases in the order Mg > Al > Zn > Fe.

Activity – 3.12 (Page. No. 92)

Question 12.
How do Metals react with Solutions of other Metal Salts ? Explain with an activity.
Answer:
Aim : To show that iron is more reactive than copper.
Materials required : Copper sulphate solution, Iron sulphate solution, Copper wire, Iron nail, Test tubes, Test tube stand, Cork, Thread.
Procedure :

1. Take a clean wire of copper and an iron nail.
2. Put the copper wire in a solution of iron sulphate and the iron nail in a solution of copper sulphate, taken in test tubes (figure).
   
3. Record your observations after 20 minutes.
4. The reaction accurs in the test tube in which iron nail is placed in a solution of copper sulphate.

Observation : The blue colour of copper sulphate solution starts fading.
Conclusion : Fe_(s) + CuSO_4(aq) → Cu_(s) + FeSO_4(aq)
Iron is more reactive than copper. This is displacement reaction.

Activity – 3.13 (Page. No. 100)

Question 13.
What are the properties of ionic compounds ? Explain with an activity.
Answer:

1. Take samples of sodium chloride, potassium iodide, barium chloride, or any other salt.
2. Take a small amount of a sample on a metal spatula and heat directly on the flame.
3. Repeat with other samples.
4. Observe the following.
   • Did the samples impart any colour to the flame ?
   • Do these compounds melt ?
5. Try to dissolve the samples in water, petrol and kerosene.
6. Make a circuit as shown in Figure and insert the electrodes into a solution of one salt.
   
7. Observe the following.
   • Are they soluble ?
   • In which solution bulb will glow ?
8. Test the other salt samples too in this manner.

Inference about the nature of these compounds :
a) Physical nature :
1) Ionic compounds are solids and are somewhat hard because of the strong force of attraction between the positive and negative ions.
2) These compounds are generally brittle and break into pieces when pressure is applied.

b) Melting and Boiling points :
3) Ionic compounds have high melting and boiling points.

c) Solubility :
4) Electrovalent compounds are generally soluble in water and insoluble in solvents such as kerosene, petrol, etc.

d) Conduction of Electricity :
5) The conduction of electricity through a solution involves the movement of charged particles.

Activity – 3.14 (Page. No. 110)

Question 14.
What condition is required to form rust on iron? Explain with an activity.
(OR)
Prove that rusting of iron takes place in the presence of air and moisture only.
Answer:
Aim : To show that air and water are necessary for rusting to take place.
Materials required : Three boiling tubes, iron nails, cork, anhydrous calcium chloride, oil.

Procedure :

1. Take three test tubes and place clean iron nails in each of them.
2. Label these test tubes A, B and C. Pour some water in test tube A and cork it.
3. Pour boiled distilled water in the test tube B, add about 1 ml of oil and cork it. The oil will float on water and prevent the air from dissolving in the water.
4. Put some anhydrous calcium chloride in test tube C and cork it. Anhydrous calcium chloride will absorb the moisture, if any, from the air. Leave these test tubes for a few days and then observe.

Observation : Iron nail get rusted in test tube A because both air and water are present in it. Iron nails do not get rusted in B because there is water but no air. In C, rusting will not take place because there is neither air nor water.
Conclusion : Iron gets rusted in the presence of air and water.