Tag: chemistry

Questions Related to chemistry

The common ingredient required for making cement and glass is:

chemistry the s-block elements (alkali and alkaline earth metals) some important compounds of calcium some important compounds of magnesium and calcium compounds of s block elements

  1. washing soda

  2. baking soda

  3. limestone

  4. potash

Show answer
Correct Option: C
Explanation:

This glass is typically made using a wet batch process where the composition is primarily limestone, soda ash and silica. 

cement is made by heating limestone (calcium carbonate) with other materials (such as clay) to $1450 ^0C$ in a kiln

Plaster of paris is obtained by heating gypsum at controlled-temperature.

chemistry the s-block elements (alkali and alkaline earth metals) some important compounds of calcium some important compounds of magnesium and calcium compounds of s block elements

  1. True

  2. False

Show answer
Correct Option: A
Explanation:

Plaster of Paris is prepared by heating gypsum to $120-180℃$.

Hence, the given statement is true that plaster of Paris is prepared by heating gypsum to controlled temperatures.

Cement is a man-made material used in building.

chemistry the s-block elements (alkali and alkaline earth metals) some important compounds of calcium some important compounds of magnesium and calcium compounds of s block elements

  1. True

  2. False

Show answer
Correct Option: A
Explanation:

Cement is manufactured through a controlled chemical combination of calcium, silicon, aluminum, iron and other ingredients. which is used in construction of building.

Limestone sand, gypsum, and coal dust are the materials required for the manufacture of cement.

chemistry the s-block elements (alkali and alkaline earth metals) some important compounds of calcium some important compounds of magnesium and calcium compounds of s block elements

  1. True

  2. False

Show answer
Correct Option: A
Explanation:

The given statement is true. Limestone, sand, gypsum and coal dust are the materials required for the manufacture of cement.

In what ratio are the mixture of cement, gravel and sand mixed to form concrete?

chemistry the s-block elements (alkali and alkaline earth metals) some important compounds of calcium some important compounds of magnesium and calcium compounds of s block elements

  1. $1:2:4$

  2. $1:3:6$

  3. Both $A$ and $B$

  4. $1:1:1$

Show answer
Correct Option: C
Explanation:

For nominal mix design, the standard ratio between cement, gravel and sand, which is as follows:

Cement          : | Gravel            : | Sand | | --- | --- | --- | --- | | M5 | 1 | 5 | 10 | | M7.5 | 1 | 4 | 8 | | M10 | 1 | 3 | 6 | | M15 | 1 | 2 | 4 | | M20 | 1 | 1 | 3 | | M25 | 1 | 1 | 2 |

Cement balls formed in its manufacturing is called:

chemistry the s-block elements (alkali and alkaline earth metals) some important compounds of calcium some important compounds of magnesium and calcium compounds of s block elements

  1. portland cement

  2. limestone

  3. clinkers

  4. alum

Show answer
Correct Option: C
Explanation:

In the manufacture of Portland cement, clinker occurs as lumps or nodules, usually 3 millimetres (0.12 in) to 25 millimetres (0.98 in) in diameter, produced by sintering (fused together without melting to the point of liquefaction) limestone and alumino-silicate materials such as clay during the cement kiln stage.

Finely powdered clay and limestone mixed with water is introduced in:

chemistry the s-block elements (alkali and alkaline earth metals) some important compounds of calcium some important compounds of magnesium and calcium compounds of s block elements

  1. drum mixer

  2. rotary kiln

  3. pan-type granulator

  4. dryer

Show answer
Correct Option: B
Explanation:

A rotary kiln is a pyroprocessing device used to raise materials to a high temperature (calcination) in a continuous process. Materials produced using rotary kilns include cement, lime.

Cement kilns are used for the pyro-processing stage of manufacture of Portland and other types of hydraulic cement, in which calcium carbonate reacts with silica-bearing minerals to form a mixture of calcium silicates.

Cement is the mixture of calcium __________ and calcium ___________, with small amount of gypsum salt.

chemistry the s-block elements (alkali and alkaline earth metals) some important compounds of calcium some important compounds of magnesium and calcium compounds of s block elements

  1. silicate, carbonate

  2. silicate, aluminate

  3. carbonate, oxide

  4. carbonate, aluminate

Show answer
Correct Option: B
Explanation:
 Compound  Formula  Shorthand form  % by $weight$ 
 Tricalcium aluminate $Ca _3Al _2O _6$  $C _3A$  10 
 Tetracalcium   $Ca _4Al _2Fe _2O _{10}$ $C _4AF$  8 
Belite or dicalcium silicate  $Ca _2SiO _5$  $C _2S$  20 
Alite or tricalcium silicate  $Ca _3SiO _4$  $C _3S$  55 
Sodium oxide  $Na _2O$  $N $
Potassium oxide  $K _2O$  $K $ upto 2 
Gypsum  $CaSO _4.2H _2O$  $CSH _2$  5 

A cement is a binder, a substance used in construction that sets and hardens and can bind other materials together. The most important types of cement are used as a component in the production of mortar in masonry, and of concrete, which is a combination of cement and an aggregate to form a strong building material.

Which of the following is/are the raw materials used to manufacture cement?

chemistry the s-block elements (alkali and alkaline earth metals) some important compounds of calcium some important compounds of magnesium and calcium compounds of s block elements

  1. Clay

  2. Limestone

  3. Calcium sulphate

  4. Slaked lime

Show answer
Correct Option: A,B
Explanation:

The most common raw rock types used in cement production are:

  1. Limestone (supplies the bulk of the lime)
  2. Clay, marl or shale (supplies the bulk of the silica, alumina and ferric oxide)
  3. Other supplementary materials such as sand, fly ash/pulverised fuel ash (PFA), or ironstone to achieve the desired bulk composition

Which of the following is used to regulate setting rate?

chemistry the s-block elements (alkali and alkaline earth metals) some important compounds of calcium some important compounds of magnesium and calcium compounds of s block elements

  1. Slaked lime

  2. Limestone

  3. Plaster of Paris

  4. Gypsum

Show answer
Correct Option: D
Explanation:

Gypsum is called the retarding agent of cement which is mainly used for regulating the setting time of cement and is an indispensable component. Without gypsum, cement clinker can condense immediately by mixing with water and release heat. The major reason is that C3A in the clinker can dissolve in water quickly to generate a kind of calcium aluminate hydrate, a clotting agent, which will destroy the normal use of cement. The retardation mechanism of gypsum is: when cement is hydrated, gypsum reacts with C3A quickly to generate calcium sulfoaluminate hydrate which deposits and forms a protection film on the cement particles to hinder the hydration of C3A and delay the setting time of cement.