Tag: chemistry

Questions Related to chemistry

Which type of solid is graphite?

chemistry solid state classification of crystalline solids classification of solids introduction to solids

  1. Ionic

  2. Molecular

  3. Metallic

  4. Covalent

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Correct Option: D
Explanation:

Graphite is covalent solid. Strong covalent bonds are present in between  C atoms in graphite. Another example of a covalent solid is diamond 

In a cubic structure of diamond which is made from X and Y, where X atoms are at the corners of the cube and Y at the face centres of the cube. The molecular formula of the compound is
chemistry solid state classification of crystalline solids classification of solids introduction to solids

  1. $X _2Y$

  2. $X _3Y$

  3. $XY _2$

  4. $XY _3$

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Correct Option: D

What is a metallic bonding?

chemistry solid state classification of crystalline solids classification of solids introduction to solids

  1. The chemical bonding that takes place from the attraction of metal atoms and the surrounding sea of electrons.

  2. The chemical bonding that takes place from the attraction of metal atoms and the other elements.

  3. The chemical bonding that takes place between metal atoms when they share electrons.

  4. The chemical bonding between electrons.

  5. The chemical bonding that takes place between metal atoms when they transfer electrons.

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Correct Option: E
Explanation:

Metallic bonding: The chemical bonding that takes place from the attraction of metal atoms and the surrounding sea of electrons.
Metallic bonding is the force of attraction between valence electrons and metal ions. It is the sharing of many detached electrons between many positive ions, where the electrons act as a "glue" giving the substance a definite structure. It is unlike covalent or ionic bonding

The electrons and the positive ions in the metal have a strong attractive force between them. Therefore, metals often have high melting or boiling points. The principle is similar to that of ionic bonds.


Hence, the correct option is $\text{E}$

Silicon carbide is a giant molecule having:

chemistry solid state classification of crystalline solids classification of solids introduction to solids

  1. covalent bond

  2. ionic bond

  3. molecular bond

  4. van der waal bond

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Correct Option: A
Explanation:
Electronegativity of silicon $= 1.9$
Electronegativity of carbon $= 2.55$
Electronegativity difference $= 2.55 - 1.9 = 0.65$ (Low) (less than $1.6$)
Hence the bond between $Si$ and $C$ in silicon carbon $(SiC)$ in covalent.

Which of the following have a triclinic system?

chemistry solid state classification of crystalline solids classification of solids introduction to solids

  1. ${K _2}C{r _2}{O _7}$

  2. $N{a _3}Al{F _6}$

  3. $NaCl$

  4. Quartz

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Correct Option: A
Explanation:

Crystal structures of various systems are:

$K _2Cr _2O _7$ - Triclinic

$NaAlF _6$ - Monoclinic

$NaCl$ - Cubic unitcell (Face centered)

Quartz – Triagonal 

According to Dalton's atomic theory, the smallest particle in which matter can exist is called :

chemistry particle nature, basic units history of atomic model atomic theory of dalton daltons atomic theory

  1. an atom.

  2. an ion.

  3. an electron.

  4. a molecule.

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Correct Option: A
Explanation:

DALTON'S ATOMIC THEORY :

1. Matter is made up of very small undivisible particle called atoms.

2. All the atoms of a given element is identical in all respect i.e. mass, shape, size, etc.

3. Atoms cannot be created nor destroyed by any chemical process.

4. Atoms of different elements are different in nature.

The atom is indivisible was proposed by :

chemistry particle nature, basic units history of atomic model atomic theory of dalton daltons atomic theory

  1. Rutherford

  2. Dalton

  3. Bohr

  4. Einstein

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Correct Option: B
Explanation:

John Dalton considered that " all matter is composed of small particle called the atom."
According to Dalton: 
-Atom is the smallest indivisible part of matter which takes part in the chemical reaction.
-Atom is neither created nor be destroyed.

The valence electrons of an element are responsible for :

chemistry particle nature, basic units history of atomic model atomic theory of dalton daltons atomic theory

  1. physical properties of an element

  2. chemical properties of an element

  3. Both A and B

  4. None of the above

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Correct Option: B
Explanation:

Valence electrons are electrons in the outermost shell and they are responsible for determining the number of bond formation and an atoms charge.This give the atom its chemical properties.

The atomic theory of matter was proposed by :

chemistry particle nature, basic units history of atomic model atomic theory of dalton daltons atomic theory

  1. John Kennedy

  2. Lavoisier

  3. Proust

  4. John Dalton

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Correct Option: D
Explanation:

The atomic theory of matter was proposed by John Dalton.

John Dalton (1766-1844) developed the first useful atomic theory of matter.

Dalton viewed chemical change as :

chemistry particle nature, basic units history of atomic model atomic theory of dalton daltons atomic theory

  1. a transfer of electrons

  2. a transfer of protons

  3. a rearrangement of atoms

  4. a change of atoms from one type into another

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Correct Option: C
Explanation:

Dalton Atomic theory postulates-

1.  All matter is made up of atoms
2. All atoms of a given element are identical in mass and properties
3. Compounds are formed by combining two or more different kind of atoms.
4. A chemical reaction is a rearrangement of atoms.