Tag: some important compounds of magnesium and calcium

Questions Related to some important compounds of magnesium and calcium

A mixture of cement, gravel, coarse sand and water is called:

  1. mortar

  2. concrete

  3. slurry

  4. hardner


Correct Option: B
Explanation:

Concrete is a building material that has high compressive strength and low tensile strength and is composed of a mixture of cement, gravel and sand (aggregates), and water.

Plaster of Paris is obtained by heating:

  1. gypsum

  2. limestone

  3. sodium carbonate

  4. calcium sulphate


Correct Option: A
Explanation:

Plaster of Paris is made by heating the mineral gypsum. When gypsum is heated to about 150°C it losses water and produces the powder of plaster of Paris.

The common ingredient required for making cement and glass is:

  1. washing soda

  2. baking soda

  3. limestone

  4. potash


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.

  1. True

  2. False


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.

  1. True

  2. False


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.

  1. True

  2. False


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?

  1. $1:2:4$

  2. $1:3:6$

  3. Both $A$ and $B$

  4. $1:1:1$


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:

  1. portland cement

  2. limestone

  3. clinkers

  4. alum


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:

  1. drum mixer

  2. rotary kiln

  3. pan-type granulator

  4. dryer


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.

  1. silicate, carbonate

  2. silicate, aluminate

  3. carbonate, oxide

  4. carbonate, aluminate


Correct Option: B
Explanation:
 Compound  Formula  Shorthand form  % by $weight$ 
 Tricalcium aluminate $Ca _3Al _2O _6$  $C _3A$  10 
 Tetracalcium   $Ca _4Al _2Fe _2O _{10}$ $C _4AF$ 
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  $CaSO _4.2H _2O$  $CSH _2$ 

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.