CLASS ASSIGNMENT 6
Alloys Corrosion, Rusting of iron and its prevention
1. Name the alloy formed by copper and zinc.
2. A utensil made of brass was kept in a kitchen. After some days, the utensils lost its lustre due to the formation of a
greenish layer on it. What could be the cause for this?
3. Which chemical element is alloyed with copper to make bronze?
4. What are the constituents of an alloy called "nickel steel"?
5. In the feed and dairy industry, a strong alloy is used for making equipments. The same alloy Is also used in making
utensils. Name the alloy and give its composition.
6. An alloy solder is used in the electronic industry to join different electronic components. What are the constituents of
solder?
7. A light and strong alloy is required for making the bodies of aircrafts. What should be its constituents?
8. Which two major constituents form the alloy duralumin?
9. What is an amalgam? Name two commonly used amalgams.
10. Pure gold is a most malleable and ductile metal. Gold used in jewellery is harder. Give reason.
11. What is the percentage of pure gold in 22 carats gold?
12. What is corrosion? What are the factors that affect the rate of corrosion? How can corrosion be prevented?
13. What is galvanisation? Which of the two galvanisation or tinning is advantageousS?
14. What happen when iron is kept exposed to humid atmosphere? Explain the process by writing chemical equation5
15. What is meant by tinning? What is the advantage of tinning.
16. Give reason for the following: Blue colour of copper sulphate solution is destroyed when iron filings are added to it.
Write the chemical equation for the reaction.
17. From the equation for the reaction Fe(s)+ Cus0,(aq)> FeSo,(ag) + Cu(s) predict which of the elements (copper or
iron) would occur higher in the reactivity series?
18. What is the metal displacement reaction ? Give one example,
19. What are the essental conditions for rusting to take place?
20. Stainless steel is made from iron by alloying it, Name the alloying metals and their proportion with respect to iron.
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Answers
Answer:
1. Brass
2.The green coating is of copper hydroxide and copper carbonate. Brass is an "alloy" of copper and zinc metal in a certain proportion. ... This process is called corrosion which is one of the types of oxidation reaction in which metal oxidized to hydroxide, oxides or carbonates.
3.Tin
4.nickel–iron alloy
5.Aluminum and its alloy
It is used to prepare lining of milk cans and milk pails. This metal does not taint the milk, it is a soft metal. Durability is reduced because the metal is impure.
6. Alloys commonly used for electrical soldering are 60/40 Sn-Pb, which melts at 188 °C (370 °F), and 63/37 Sn-Pb used principally in electrical/electronic work. This mixture is a eutectic alloy of these metals, which: has the lowest melting point (183 °C or 361 °F) of all the tin-lead alloys.
7. The alloy is duralumin and its constituents are aluminium and copper with traces of manganese and magnesium.
8.In addition to aluminium, the main materials in duralumin are copper, manganese and magnesium.
9.it is a mixture of mercury and another metal, used especially to fill holes in teeth.
gold and silver mining since it amalgamates
10.Gold is the most malleable and ductile of all known metals. A single ounce of gold can be beaten into a sheet measuring roughly 5 meters on a side. Thin sheets of gold, known as gold leaf, are primarily used in arts and crafts for gilding.
11. 22-karat gold is 91.6% gold
12.Corrosion is a natural process that converts a refined metal into a more chemically stable form such as oxide, hydroxide, or sulfide. There are several factors influencing the rate of corrosion including diffusion, temperature, conductivity, type of ions, pH value and electrochemical potential.Metal Type. One simple way to prevent corrosion is to use a corrosion resistant metal such as aluminum or stainless steel. ...
Protective Coatings. The application of a paint coating is a cost-effective way of preventing corrosion. ...
Environmental Measures. ...
Sacrificial Coatings. ...
Corrosion Inhibitors. ...
Design Modification.
13. The advantage of galvanising iron by tin plated iron is it prevents it from rusting.
Explanation:
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