Why are oxides easier to reduce?
The concentrated ore must be converted into a form which is suitable for reduction. Usually the sulphide ore is converted to oxide before reduction. Oxides are easier to reduce.
What are the principles of isolation?
The isolation principle rests on defining internal and external differentiation for each subset of at least two objects. Subsets with larger external than internal differentiation form isolated groups in the sense that they are internally cohesive and externally isolated.
Why reduction of MXS is difficult?
The ΔGo vs T lines for CO show negative slope at high temperature. Hence, it can easily reduce copper oxide to copper. However, ΔGf for sulphide ores are higher than that for CS2 (which is an endothermic compound). Hence, the extraction of copper from pyrite ore is difficult.
What is isolation speciation?
Speciation involves reproductive isolation of groups within the original population and accumulation of genetic differences between the two groups. In allopatric speciation, groups become reproductively isolated and diverge due to a geographical barrier.
What are the five basic principles for infection control?
These include standard precautions (hand hygiene, PPE, injection safety, environmental cleaning, and respiratory hygiene/cough etiquette) and transmission-based precautions (contact, droplet, and airborne).
What is the mechanism of speciation?
The key to one species diverging into two or more different species is establishing a barrier to gene flow. In this way, geographic isolation may lead to reproductive isolation and the formation of new species. Allopatric speciation is thought to be the main mechanism of speciation among most groups of organisms.
What is the importance of isolation?
Isolation or cohorting of infected patients is an old concept. Its purpose is to prevent the transmission of microorganisms from infected or colonized patients to other patients, hospital visitors, and health care workers, who may subsequently transmit them to other patients or become infected or colonized themselves.
What is isolation of elements?
The extraction and isolation of metals from ores involve the following major steps: • Concentration of the ore, • Isolation of the metal from its concentrated ore, and • Purification of the metal. The entire scientific and technological process used for isolation of the metal from its ores is known as metallurgy.
What are the 5 types of isolation?
There are five isolation processes that prevent two species from interbreeding: ecological, temporal, behavioral, mechanical/chemical and geographical.
What is standard isolation?
Standard Precautions are the basic IPC precautions in health care. They are intended to minimize spread of infection associated with health care, and to avoid direct contact with patients’ blood, body fluids, secretions and, non-intact skin.
Can zinc be reduced by hydrogen?
In relation to the EAF dust sample, the results indicate that zinc can be selectively extracted through reaction with H2 at temperatures in the range between 1123 K and 1143 K (850 °C and 870 °C).
What is the principle of leaching?
Leaching is the process of extracting minerals from a solid by dissolving them in a liquid(not always a solvent). The soluble particles dissolve in to the liquid leaving back insoluble particles which may be seperated comfortably.
What are isolation mechanisms?
Isolating mechanisms are intrinsic characteristics of species that reduce or prevent successful reproduction with members of other species. Viewed genetically, they are characters that act as barriers to the exchange of genes between populations.
Is general principles and processes of isolation of elements?
The entire scientific and technological process used for isolation of the metal from its ore is known as metallurgy. The extraction and isolation of an element from its combined form involves various principles of chemistry. Still, some general principles are common to all the extraction processes of metals.
Why the zinc produced inside the furnace is a gas?
Under the conditions in the furnace zinc is a vapour (gas), whereas lead is produced as a liquid by a similar series of reactions. The zinc vapour is carried into the condenser in a stream of carbon monoxide and carbon dioxide gases (at about 1300 K) and condensed by adsorption in a spray of liquid lead.
How does isolation help speciation?
It’s a mechanism of speciation that happens when populations of a species are divided by a geographic barrier. Populations can become separated by rivers, mountains, or bodies of water. Over time, the two populations become reproductively isolated and they evolve separately.
What is difference between coke and coal?
Charcoal is a fuel that comes from the incomplete burning of wood. Coke is a fuel that is obtained from the calcination or dry distillation of mineral coal. It is composed of carbon and has a high calorific value, but it is highly polluting.
What are 3 types of isolation?
- 3 Types of Reproductive Isolation. These are “_________________________ mechanisms” that could lead to speciation.
- Geographic Isolation. _______________________________________ occurs when two populations are separated _____________________________ by geographic barrier.
- Temporal Isolation.
- Behavioral Isolation.
How is pure zinc removed from the furnace and collected?
The process starts by charging solid sinter and heated coke into the top of the blast furnace. Slag and lead collect at the bottom of the furnace and are tapped off regularly. The zinc is scrubbed from the vapour in the condenser via liquid lead. The liquid zinc is separated from the lead in the cooling circuit.
Why is reduction necessary for zinc?
Due to its very low boiling point, at such temperatures, zinc will escape with exhaust gases. Zinc Blende does not contain a very high percentage of zinc and hence it needs to be concentrated.
What are the methods of extraction of metals?
There are 3 main methods of extracting metals from their ore. They are reduction of the ore with carbon, reduction of the molten ore by electrolysis, and reduction of the ore with a more reactive metal.
How Coke is used in extraction of metals?
Answer. Answer: Answer:The role of coke in the extraction of iron from its oxides is that it reduces the iron oxide to molten iron metal. Coke also when burnt in the blast furnace, supplies the heat required for carrying out the extraction of iron from its oxide.
Why Coke is used as reducing agent?
Coke is a good reducing agent, especially at higher temperatures, because it is a non-metal and it combines with oxygen and forms its gaseous non-metallic oxides. It helps in oxidation.
Can zinc be extracted by self reduction?
Zinc cannot be extracted by self-reduction process as Zinc Sulphide and oxide cannot react.
Why is sulphide roasted before reduction?
A metal oxide is generally less stable than the metal sulfide. Thus, reduction of metal oxide is easier than the reduction of metal sulfide. Hence, a sulfide ore is first converted into it’s oxide before reduction. This process is known as roasting.
Can zinc oxide be reduced by carbon?
Zinc oxide can be reduced to zinc by using carbon monoxide , but aluminium oxide cannot be reduced by a reducing agent .
Why is zinc blende ore roasted before carbon reduction?
Answer: Extraction of Zinc : The zinc is extracted from its ore zinc blende (ZnS). The concentrated ore is then roasted in presence of excess of air at 1200 K. If roasting is carried out below this temperature, ZnS is converted into ZnSO4, which convert back to ZnS during carbon reduction of roasted ore.
Which reaction is used to increase the temperature inside the blast furnace?
The reaction between oxygen and carbon is exothermic and is responsible for increasing the temperature of the blast furnace.
What are 4 types of isolation?
According to the CDC, the three standard categories of transmission-based precautions include contact isolation, droplet isolation, and airborne isolation.
- Standard Precautions.
- Contact Isolation.
- Droplet Isolation.
- Airborne Isolation.
How is calcination different from roasting?
Roasting involves heating of ore lower than its melting point in the presence of air or oxygen. Calcination involves thermal decomposition of carbonate ores. During calcination, moisture is driven out from an ore. Roasting does not involve dehydrating an ore.