منزل 
مشروع
· (d) Carbonate and sulphide ores are usually converted into oxides during the process of extraction. Answer: (a) Platinum, gold and silver are very less reactive and do not corrode. They also possess very brilliant lustre. So, they are used in jewellery. (b) Metals such as potassium and sodium react so vigorously that they ch fire if kept in ...
HgS + O 2 → Hg + SO 2. (iv) Iron pyrite (FeS 2) is converted into ferric oxide (Fe 2 O 3) by roasting. 4FeS 2 + 11O 2 → 2Fe 2 O 3 + 8SO 2. Thus, both calcination and roasting produce oxide of the metal. However, there are a few points of difference between the two processes. Chloride ores remains unchanged by calcination or roasting.
Ans: ZnCO is converted into ZnO and CO 2 gas is produced. ZnCO 3 > ZnO + CO 2 e) ... for carbonate and hydrated oxide ores. 2. Roasting is used for sulphide ores. 3. Volatile impurities can be removed 3. Moisture organic impuritiesand other volatile impurity are removed.
Extraction of iron metal from iron oxide ore is carried out by heating with coke and flux (calcium carbonate). Flux is a slag forming substance. It converts infusible impurities into fusible (s) → Fe (s) + 32 O2 (g) is not a spontaneous process. Fe2O3 is converted to FeO at about 400°C. FeO is converted to Fe at about 800 1000°C.
· 2HgO →Heat 2Hg + O 2 * Copper from copper sulphide Cu 2 S + 3O 2 →Heat 2Cu 2 O _ 2SO 2 2Cu 2 O + Cu 2 S →Heat 6Cu + SO 2 Extracting Metals in the Middle of Activity Series : *Metals are easier to obtain from oxide ores, thus, sulphide and carbonate ores are converted into oxides.
· P 4 + 5O 2 → 2P 2 O 5 4As + 5O 2 → 2As 2 O 5. iii. Carbonate or hydroxide ores are decomposed into oxides ores. ZnCO 3 (calamine) → ZnO + CO 2 CuCO (OH) 2 (malachite) → 2CuO + CO 2 + H 2 O. iv. Water of crystallization is removed. 2Fe 2 .
The sulphide ores are converted into oxides by heating strongly in the presence of excess air which is known as roasting. The carbonate ores are changed into oxides by heating strongly in limited air which is known as calcination. The metal oxides are then reduced to the corresponding metals by using suitable reducing agents such as carbon.
· 1) It is the process by which a carbonate ore is heated strongly in the absence of air to convert into metal oxide. It is a process in which sulphide ore is heated in the presence of air to convert into metal oxide. 2) ZnCO 3 —>ZnO + CO 2: 2ZnS—>2ZnO+2 SO 2 + 3 O 2
· The sulphide ores are converted into oxides by heating strongly in the presence of excess air which is known as roasting. The carbonate ores are changed into oxides by heating strongly in limited air which is known as calcination. The metal oxides are then reduced to the corresponding metals by using suitable reducing agents such as carbon.
· Carbonate and sulphide ores are usually converted into oxides during the process of extraction. Answer: 1. Platinum, gold and silver are used to make jewellery because they are very lustrous. Also, they are very less reactive, ductile and do not corrode easily. 2.
(d) Carbonate and sulphide ores are usually converted into oxides during the process of extraction. A : (a)Platinum, gold and silver are used to make jewellery because they are inert (b) Sodium, potassium and lithium are stored under oil because when they come in contact with air they form their oxides which are explosive in nature
3) Purifiion of the ore. Question 9: Carbonates and sulphide ores are usually converted into oxide ores, why? Answer: It is easier to reduce oxide as compared to carbonate and sulphide. Question 10: Name the types of reduction processes involved in metallurgy with an example for each.
· Extraction of Crude Metal from Concentrated Ore. The process of working of the concentrated ore to extract metal depends upon the nature of the ore as well as the nature of the impurities present in t he ore.. The concentrated ore must be converted into a form which is suitable for reduction. Generally, the sulphide ores are converted to oxides before reduction because oxides .
· (d) Carbonate and sulphide ores are usually converted into oxide during the process of extraction. Ans – (a) Au, Ag, Pt are highly lustrous, malleable and ductile and least reactive metal, so they are used to make jewellery.
· So, roasting is not done for carbonate ores, moreover, calcination is more difficult than roasting. It is easier to obtain metals from their oxides (by reduction) than from carbonates or sulphides. So before reduction can be done, the ore is converted into metal oxide.
24 ساعة