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.

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.

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.

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 C_nH_2n 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?

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

Class 10 - Carbon and Its Compounds

cellulose
(credits:wpclipart)

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.