Showing posts with label class10-chemistry. Show all posts
Showing posts with label class10-chemistry. Show all posts

Friday, 26 October 2012

CBSE Class 9/10 - Science - All about Names of the Chemical Elements

All about Names of the Chemical Elements

All about Names of the Chemical Elements

1. There are 115 chemical elements known today to the world. Only 90 are found in nature and the rest are artificially created.

2. A good number of elements are named after human beings and mythological figures.

Monday, 13 August 2012

CBSE Class 10 - Science - Ch14 - Sources of Energy

Sources of Energy 
(Q & A)

Q1: Fill in the blanks.
(a) Hydro power plants convert _________ energy of falling water into electricity.

(b) When wood is burnt in a limited supply of oxygen, ______ is left behind as residue.

(c) Gases like ______, _____, ______ and ______ are generated in a biogas plant.

(d) Biogas contains _____ % methane.

(e) To maintain the required speed of the turbine, wind speed should be higher than _____.

(f) To establish 1 MW generator, the wind energy farm needs about ___ hectares of land.

(g) Ocean Thermal Energy plants can operate if the temperature difference between the water at the surface and water at depths up to ______ km is _______ or more.

(h) ______ and _______ countries have number of power plants based on geothermal energy.


Saturday, 4 August 2012

CBSE Class 10 - Science - CH3 - Metals and Non-Metals (MCQs)

Check in Periodic Table
How many metals, non-metals and metalloids?
Metals and Non-Metals

1. Which of the following is the best electrical conductor?
(a) Gold
(b) Silver
(c) Copper
(d) Aluminium

Thursday, 19 July 2012

CBSE Class 10 - Science - CH2 - Acids, Bases and Salts

Acids, Bases and Salts
MCQs, NCERT Solutions, Q & A

Q1: The most commonly used indicator in laboratory is
(a) Methyl Orange
(b) Litmus
(c) Phenolphtalein
(d) Universal Indicator

Answer:  Universal Indicator

Q2: Olfactory indicators are:
(a) Clove
(b) Turmeric
(c) Soap
(d) Rose Petals

Answer: (a) Clove

Tuesday, 10 July 2012

How to learn naming Chemical Formulae?

Nomenclature of Simple Inorganic compounds.

1. A formula is a shorthand notation used to identify the composition of a molecule or compound.

2. For example chemical formula of water is H2O. It includes the symbol of each element (e.g. Hydrogen:H and Oxygen:O)  in the molecule, along with numerical subscripts to show how many atoms of each element are present.

3. Most of the inorganic compounds are binary compounds i.e. it consists of two elements. Some are ternary i.e. contain more than two elements.

Monday, 16 April 2012

Class 10 - Science - Ch1 - Chemical Reactions & Equations

Ch1 - Chemical Reactions & Equations
MCQs, Q & A, NCERT Solutions

Q1:  A chemical reaction involves in
a. Only breaking of bonds
b. Only formation of bonds
c. Both breaking and formation of bonds
d. None of these

Answer: (c)  Both breaking and formation of bonds

Q2: A balanced chemical equation always obeys
a. Law of conservation of mass
b. Law of thermal equilibrium
c. Law of conservation of energy
d. All of the above

Answer: (a) law of conservation of mass.

Friday, 3 February 2012

CBSE- Class X - Ch5 - Periodic Classification of Elements

Periodic Classification of Elements 

(Chapter Notes and CBSE exam questions and answers)

Modern Periodic Table
Vertical Columns or Groups
There are 18 groups in the periodic table.

  1. First group elements are called alkali metals.
  2. Second group elements are called alkaline earth metals. They are not as soft as Group 1.
  3. Groups three to twelve are called transition elements.
  4. Group 1, 2 and 13 - 18 are called normal elements or main group elements or representative elements.
  5. Group 16 elements are called chalcogens (except polonium).
  6. Group 17 elements are called the halogen family.
  7. Group 18 elements are called noble elements (earlier called inert gas group).
  8. The lanthanides and actinides which form part of group 3 are called inner transition elements.
Horizontal Rows or Periods
Horizontal Rows are called periods in the Periodic Table. There are seven periods or rows.

Tuesday, 13 December 2011

CBSE - Class 10 - Ch4 - Soaps and Detergents

Soaps and Detergents

Soap & Detergents (Concept Map)
Q1: Why soap does not work well with hard water containing Ca2+ or Mg2+ ions?

Answer: Because it reacts with Ca2+ or Mg2+ to forma white precipitate which is called scum and soap goes waste. Therefore soap forms no or little lather with hard water.

Saturday, 5 November 2011

Class 10 - Chapter 4- Carbon and its Compunds (Short Questions & Answers)

Class 10 - Chapter 4- Carbon and its Compounds
Methane Structure
(Short Questions & Answers)

Q1: State whether the following are true or false
       a. Both alkenes and cyclo-alkanes both can be represented by the same general formula.
       b. The general formula CnH2n is valid for any alkene with any number of multiple bonds,
       c. Acetone is the common name of propanone.
       d. Isomers always show same chemical properties.

Q2: Which is the common name for ethyne?

Q3: The complete combustion of a hydrocarbon always gives .....?

Q4: What is the term used for the compounds which have same molecular formula but
       different structures?

Sunday, 23 October 2011

Class 10 - Science - CH4 - Carbon and Its Compounds (Q & A) (#cbsenotes)(#eduvictors)

Class 10 - Carbon and Its Compounds

Class 10 - Science - CH4 - Carbon and Its Compounds (Q & A) (#cbsenotes)(#eduvictors)

Q1. What is next homologue of C3H7OH is called?

Answer: The next homologue of C3H7OH is called butanol C4H9OH.

Q2. What is the molecular formula of the alcohol which can be derived from propane?

Answer: Propane: CH3-CH2-CH3 or C3H8
Alcohol obtained from propane is C3H7OH.

Q3. What is meant by the term functional group?

Answer: An atom or a group of atoms, which makes a carbon compound reactive and decides its
properties. is called a functional group.

Q4. Give the names of the functional groups: (CBSE 2007)
          i) -CHO  (ii  -C=O

Answer: (i) Aldehydic group (ii) Ketonic group.

Q5. Give the names of the following functional groups: (CBSE 2007)
         i) —OH (ii) —COOH

Answer: (i) Alcoholic (ii) Carhoxylic.