Script editor is where you edit your programs or your sprite's pictures.

The script editor has three main parts:

(i) Script area: Where you build scripts.
(ii) Block menu: Where you choose the category of blocks (programming statements) to use.

(iii) Block palette: Where you choose the block to use.

(i) Stage is the background appearing when we open the scratch window.

(ii) The background will most often be white. We can change the background colour as we like.

Bessemerisation:

(i) The molten matte is transferred to Bessemer converter in order to obtain blister copper.

(ii) Ferrous sulphide from matte is oxidized to ferrous oxide, which is removed as slag using silica.

\(\begin{aligned} & 2 \mathrm{FeS}+3 \mathrm{O}_2 \longrightarrow 2 \mathrm{FeO}+2 \mathrm{SO}_2 \uparrow \\ & \mathrm{FeO}+\mathrm{SiO}_2 \longrightarrow \underset{\text { (Iron silicate) }}{\mathrm{FeSiO}_3 \text { (slag) }} \end{aligned}\)

\(\begin{aligned} & 2 \mathrm{Cu}_2 \mathrm{~S}+3 \mathrm{O}_2 \longrightarrow 2 \mathrm{Cu}_2 \mathrm{O}+2 \mathrm{SO}_2 \uparrow \\ & 2 \mathrm{Cu}_2 \mathrm{O}+\mathrm{Cu}_2 \mathrm{~S} \longrightarrow \\ & 6 \mathrm{Cu}+\mathrm{SO}_2 \uparrow \\ & (\text { Blister copper }) \end{aligned}\)

When iron is exposed to moist air, it forms a layer of brown hydrated ferric oxide on its surface. This compound is known as rust and the phenomenon of formation of rust is known as rusting

\(4 \mathrm{Fe}+3 \mathrm{O}_2+\mathrm{xH}_2 \mathrm{O} \longrightarrow 2 \mathrm{Fe}_2 \mathrm{O}_3 \cdot \mathrm{xH}_2 \mathrm{O} \text { (rust) }\)

(i) Scratch is a software used to create animations cartoons and games easily.

(ii) Scratch is a Visual Programming Language.

(iii) It was developed in the Massachusetts Institute of Technology (MIT) Media Lab to make programming easier and more fun to learn.

Scratch Environment Editor :

(iv) The Scratch editor has three main parts: They are Stage, Sprite and Script editor.

(v) Stage: Stage is the background appearing when we open the scratch window. The background will most often be white. You can change the
background colour as you like.

(vi) Sprite:

◆ The characters on the background of a Scratch window are known as Sprite.

◆ Usually a cat appears as a sprite when the Scratch window is opened. The software provides facilities to make alterations in sprite.

(vii) Script editor/ Costume editor: Where you edit your programs or your sprites pictures.

The script editor has three main parts :

(i) Script area: Where you build scripts.

(ii) Block menu: Where you choose the category of blocks (programming statements) to use.

(iii) Block palette: Where you choose the block to use.

Methods of preventing corrosion :

Alloying:

(i) The metals can be alloyed to prevent from the process of corrosion

(ii) E.g: Stainless Steel

Surface Coating: It involves application of a protective coating over the metal. It is of the following types

(a) Galvanization: It is the process of coating zincon iron sheets by using electric current

(b) Electroplating: It is a method of coating one metal over another metal by passing electric current

(c) Anodizing:

(i) It is an electrochemical process.

(ii) It converts the metal surface into a decorative,durable and corrosion resistant.

(ii) Aluminium is widely used for anodizing Process

(d) Cathodic Protection:

(i) It is the method of controlling corrosion of a metal surface protected is coated with the metal which is easily corrodible.

(ii) The easily corrodible metal is called Sacrificial metal to act as anode ensuring cathodic protection.

Smelting (in a Blast Furnace):

(i) The charge consisting of roasted ore, coke and limestone in the ratio 8:4:1

(ii) Smelted in a blast furnace by introducing it through the hopper arrangement at the top.
(iii) There are three important regions in the furnace

a) The Lower Region (Combustion Zone):

(i) The temperature is at 1500°C.
(ii) Hot gases Coke burns with oxygen to form CO₂ when the charge comes in contact with a hot blast of air.

\(\mathrm{C}+\mathrm{O}_2 \xrightarrow[\Delta]{1500^{\circ} \mathrm{C}} \mathrm{CO}_2+\text { Heat }\)

It is an exothermic reaction since heat is liberated

(b) The Middle Region (Fusion Zone):

(i) The temperature prevails at 1000°C.

(ii) CO₂ is reduced to CO

\(\mathrm{CO}_2+\mathrm{C} \xrightarrow[\Delta]{1000^{\circ} \mathrm{C}} 2 \mathrm{CO}+\text { Heat }\)

Limestone decomposes to calcium oxide and CO₂

\(\mathrm{CaCO}_3 \xrightarrow[\Delta]{1000^{\circ} \mathrm{C}} \mathrm{CaO}+\mathrm{CO}_2-\text { Heat }\)

(iii) These two reactions are endothermic due to absorption of heat.

(iv) Calcium oxide combines with silica to form calcium silicate slag.

\(\mathrm{CaO}+\mathrm{SiO}_2 \longrightarrow \mathrm{CaSiO}_3\)

(c) The Upper Region (Reduction Zone):

(i) The temperature prevails at 400°C.

(ii) Carbon monoxide reduces ferric oxide to form a fairly pure spongy iron.

\(\mathrm{Fe}_2 \mathrm{O}_3+3 \mathrm{CO} \xrightarrow{400^{\circ} \mathrm{C}} 2 \mathrm{Fe}+3 \mathrm{CO}_2 \uparrow\)

The molten iron is collected at the bottom of the furnace after removing the slag.

(iii) The iron thus formed is called pig iron.
(iv) It's remelted and cast into different moulds. This iron is called cast iron.

Scratch is a software used to create animations, cartoons and games easily.

(i) LINUX

(ii) WINDOWS

An amalgam is an alloy of mercury with another metal

(i) Household utensils

(ii) Electrical cable industry

(iii) Aeroplanes and other industrial parts

On heating at 800°C, aluminium burns very brightly forming it's oxide and nitride

\(\begin{aligned} & 4 \mathrm{Al}+3 \mathrm{O}_2 \rightarrow 2 \mathrm{Al}_2 \mathrm{O}_3 \text { (Aluminium oxide) } \\ & 2 \mathrm{Al}+\mathrm{N}_2 \rightarrow 2 \mathrm{AlN} \text { (Aluminium nitride) } \end{aligned}\)