Diamond, graphite, and coal are all forms of carbon.
Diamond has a relative density of 3.5, graphite is a black and shiny material with a relative density of 2.25, and coal is a solid form of carbon that is often used as fuel.
All three of these substances contain carbon.
3. Arrange the following substances in chronological order of their first synthesis in the lab : 1. Black gold
2. Fullerene 3. Graphene
4. Kevlar Select the correct answer from the codes given below : Codes :
Kevlar is a strong and heat-resistant material created by Stephanie Kwolek at Dupont lab in the USA in 1965.
Harold Kroto, Richard E. Smalley, James R. Heath and Robert F. Curl Jr. discovered Fullerene in 1985.
Graphene, a form of carbon, was first made in 2004 by Andre Geim and Konstantin Novoselov at the University of Manchester.
In 2019, scientists at the Tata Institute of Fundamental Research (TIFR) used gold nanoparticles and changed their size and space between them to create a new material called ‘black gold‘, which can absorb light and carbon dioxide.
4. Which of the following is made up of Carbon only?
Graphite and Diamond both are allotropes of Carbon.
Pencil lead are made of Graphite mixed with a clay binder which leaves grey or black marks that can be easily erased.
9. The third allotrope of Carbon was discovered by three scientists, who were awarded the Nobel Prize for Chemistry. Find out who was not on that team–
In 1996, Robert F. Curl, Sir Herald W. Kroto, and Richard E. Smalley won the Nobel Prize in Chemistry for finding Fullerenes, an arrangement of Carbon where molecules are packed together.
This arrangement of Carbon has the molecular formula C60 and was named after the famous American architect and inventor, Richard Buckminster Fuller.
10. Which one of the following pairs is not correctly matched?
Ans. (d) Fullerene : Organic compound containing fluorine
Fullerene is a type of carbon.
Buckminsterfullerene is a spheroid molecule made of 60 carbon atoms connected with single and double bonds, forming 12 pentagons and 20 hexagons, which looks like a soccer ball.
12. Which one of the following pairs is not correctly matched?
(a) Fullerene – Organic compounds containing fluorine
(b) Dry Ice – Solid carbon dioxide
(c) Keratin – Protein found in the outer layer of human skin
(d) Mustard gas – Poisonous liquid used in chemical warfare
Salt, Sugar, Diamond, Quartz, Ice, and Graphite all come in the form of crystals, but Sulphur does not.
Sulphur is a type of chemical element that doesn’t contain metal.
20. Consider the following statements: Glass can be etched or scratched by – 1. Diamond
2. Hydrofluoric Acid 3. Aquaregia
4. Conc. Sulphuric Acid Which of these statements are correct?
Diamonds are used to scratch glass, and hydrofluoric acid is one of the strongest acids used for industrial processes, such as etching glass, cleaning metal and making electronics.
21. For the ceiling of diamonds, the unit of weight is a carat. One carat is equal to –
The carat is a unit for measuring the weight of gems and pearls, and is equal to 200 milligrams.
22. Graphene has been frequently in the news recently. What is its importance?
1. It is a two-dimensional material and has good electrical conductivity. 2. It is one of the thinnest but strongest materials tested so far. 3. It is entirely made of silicon and has high optical transparency. 4. It can be used as ‘conducting electrodes’ required for touchscreens, LCDs, and organic LEDs.
Which of the statement(s) given above is/are correct?
(a) 1 and 2
(b) 3 and 4
(c) 1, 2 and 4
(d) 1, 2, 3 and 4
Graphene is an ultra-thin Carbon molecule that has amazing qualities.
In 2004, Andre Geim and Kostya Novoselov from Manchester University discovered it.
For this discovery, they were awarded the Nobel Prize in 2010.
They extracted Graphene from a Graphite sample. Graphene has two dimensions, which makes it easier to control electricity compared to three-dimensional elements.
It is very thin, yet the strongest material tested so far.
It is also almost transparent, yet dense enough that even the smallest gas molecules can’t pass through it.
Graphene is used in computer chips, communication devices and touchscreens as conducting electrodes.
23. Which one of the following materials is strongest?
(a) German Silver
(b) Brass
(c) Steel
(d) Graphene
Graphene is incredibly thin but also very strong and is so dense that not even the smallest gas molecules can pass through it.
24. Consider the following statements and select the correct answer from the codes given below – (1) Water becomes harder due to the presence of Calcium Sulphate and it is not usable. (2) Diamond is harder than copper and iron. (3) Oxygen is the main component of air. (4) Nitrogen is used in the manufacture of vegetable ghee. Code :
Molecular orbital theory states that the bond order is calculated by subtracting the number of electrons in the antibonding orbitals from the number of electrons in the bonding orbitals and then dividing the result by two.
