CBSE Class 11: Chemistry - CH1 - Laws of Chemical Combinations #chemistry #eduvictors

Antoine Lavoisier
credits:wikipedia

Laws of Chemical Combinations

Q1: List the laws that are collectively called Laws of Chemical combinations.

Answer:

1. Law of Conservation of Mass
2. Law of Constant Composition
3. Law of Multiple proportions
4. Law of reciprocal proportions
5. Law of Combining Volumes (Gay Lussac's law of Gaseous Volumes)
6. Avogadro Law

CBSE Class 9 - Maths - Ch6 - Lines and Angles (Set-2)

Octahedron

Lines and Angles: Q & A

Q1: Prove that two lines which are both parallel  to the same line, are parallel to each other.

Answer: 

Given: Three lines l, m, n in a plane such that l || m and m || n.

CBSE Class 9 English Communicative SA1 Sample Paper

Class 9 - English Communicative - SA1 - Paper

CBSE Class 11 - Chemistry - CH1 - Mole Concept

Q1: Define mole

Answer: A mole (or mol) is defined as the amount of substance which contains equal number of  particles (atoms / molecules / ions) as there are atoms in exactly 12.000g of carbon-12.

One mole of carbon-12 atom has a mass of exactly 12.000 grams and contains 6.02 × 10²³ atoms.

A mol is just a number like a dozen. A dozen equals to 12 eggs , a gross of Pencil equals to 144 Pencil. Similarly, mol is equal to 6.022 × 10²³(Avagadro constant). Mol is also known as chemist dozen.

CBSE Class 8 - Science - Ch4 - Metals and Non-Metals #eduvictors

Metals and Non-Metals

Class 8 - NCERT Chapter Solutions

Q1. Which of the following can be beaten into thin sheets?
(a) Zinc
(b) Phosphorus
(c) Sulphur
(d) Oxygen

Answer: (a) Zinc, as it is a metal. The rest of these are non-metals.

Q2. Which of the following statements is correct?
(a) All metals are ductile.
(b) All non-metals are ductile.
(c) Generally, metals are ductile.
(d) Some non-metals are ductile.

Answer: (c) Generally, metals are ductile.
Mercury (metal) is liquid at room temperature and cannot be drawn into wires. Therefore, it is non-ductile.

NTSE examination shifts to class 10

NCERT announced the date of NTSE examination for class 10. Earlier the examination was conducted for students of standard 8.
Stage I (State)
Last Date for Submission of Application Form                             - 31st August, 2012

Examination in Mizoram, Meghalaya, Nagaland and
Andaman and Nicobar Islands                                                       - 17th November, 2012 (Saturday)



Examination in All other States and                                               - 18th November 2012 (Sunday)
Union Territories


Stage II (National)
Examination in All States and Union Territories                           - 12th May, 2013 (Sunday)

CBSE - Class 9 - Science - CH8 - Motion (WorkSheet) #eduvictors

Class 9 - Ch8 - Motion

Fill in the blanks

1. If the position of an object does not change with time, it is said to be at _____.

2. Rest and Motion are ___________ (absolute/relative) terms

3. The study of motion without taking into account the cause of motion is called ______ (kinematics/dynamics).

4. An object is said to be at ________ (rest/motion) if it changes its position with respect to its surroundings in a given time