Saturday, 14 April 2018

8 Simple and easy ways of effective use of technology in the classroom


1. Create A Simple Class Website: You can create a class website using simple and ready-to-use hosts like Google Classroom or http://www.edmodo.com.
You can also  create your own website using these free providers.
1.     Wix - http://www.wix.com/
2.     Wordpress – http://www.wordpress.com
3.     Weebly - http://www.weebly.com/
2. Online Quizzes and Exit Cards: You can easily create free online quizzes and exit tickets using the following sites:
1.      Kahoot - https://getkahoot.com/
2.     Socrative - http://www.socrative.com/
3.     Plickers – http://www.plickers.com
3. Online Field Trips: A new effort provided by technology  in  the field of education is the online field trip where you can visit anything from the International Space Station to the White House and even the Hershey’s Chocolate Factory for free. The trip comes to your classroom through a program like Skype Education - https://education.skype.com/ or Google’s Connected Classrooms - https://connectedclassrooms.withgoogle.com/. All you need is an Internet connection. For more information on online field trips please check out: http://www.eschoolnews.com/2013/04/07/ten-of-the-best-virtual-field-trips/
4. Flip Your Classroom: Try out the flipped classroom. Record your lessons using your computer, lesson (PowerPoint, Word, PDF, etc.) and some free software. Once it’s ready to go, upload it to YouTube (unlisted if you only want your students seeing it). This is a great way to free-up learning time in the classroom. If you don’t want to create your own videos there are plenty of people online who have already created them and these can be accessed for free via http://www.youtube.com. Click here to learn more about flipping your classroom - http://www.teachwithfergy.com/the-flipped-classroom-how-to-flip-your-class-and-increase-student-success/
5. Genius Hour: Have you heard of Genius Hour? It’s so easy to understand and use. Kids love it. It is  easy to implement and it gets your kids to do something they are passionate about. Click here to learn more about using Genius Hour your classroom - http://www.teachwithfergy.com/genius-hour-have-you-tried-it-yet/
How can your STUDENTS get involved right away?
6. Create virtual masterpieces: Get your students to show their creative side and technological skills by producing a virtual masterpiece such as a Prezi, a website, an app or an infographic. Genius Hour works very well here as well (see point #5).
• Prezi - https://prezi.com/
• For more information on infographics visit - http://www.creativebloq.com/infographic/tools-2131971
7. Simulations: Let your kids interact and become more engaged using a variety of free online simulations and applications. Don’t have iPads in your classroom? No problem. Simulations and videos can be accessed free of charge and provide a learning experience that students wouldn’t be able to tap into during a normal school day. This can be due to monetary or safety issues (some demonstrations can be very expensive and/or dangerous).
 Check out https://phet.colorado.edu/ (100% free) .This site allows students to get hands-on with the content and bring learning to life. The simulations also offer full walkthroughs and guided activities, which can be accessed for free and come with an answer key.
8. Podcasts:
Have your kids make a podcast as their project submission or make it an ongoing, semester-long assignment. It’s a lot easier than you may think and opens up a lot of unique and useful possibilities. Check out http://www.educationworld.com/a_tech/tech/tech252.shtml to get started

Friday, 13 April 2018

WORKSHEET:CHEMISTRY PRACTICAL

TOPIC : MOLARITY

Fill in the gap with suitable word/symbol/phrase

Q No
Question
Answer
1
The number of moles of the solute present per ………………of solution is called molarity.
………….
2
The number of moles of the solute present per ………………of solution is called molality.
………….
3
The unit of molarity is ………………….
………….
4
The unit of molality is ………………….
………….
5
The mass of the solute (WB) divided by its molecular mass (MB) gives the ………………of the solute.

………….
6
The number of moles of a solute (n) x molecular mass of the solute (MB) = …………………of the solute

………….
7
1mL=…………….L
………….
8
1L= ………deciL
………….
9
1mL=……..cm3
………….
10
1000cm3 =…….L
………….
11
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………….
12
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………….
13
If 500 mL of a 5M solution is diluted to 1500 mL, the molarity of the diluted solution will be………………

………….
14
If the concentration of glucose (C6H12O6) in blood is 0.9 g L–1, then its molarity shall be………

………….
15
The molality of the solution containing 18.25 g of HCl gas in 500 g of water?
………….
16
Sulphuric acid reacts with sodium hydroxide as follows:
H2SO4 + 2NaOH → Na2SO4 + 2H2O
When 1L of 0.1M sulphuric acid solution is allowed to react with 1L of 0.1M sodium hydroxide solution, the amount of sodium sulphate formed and its molarity in the solution obtained is………………….&…………………………



………….
………….
17
Which of the following solutions have the same concentration?
(i) 20 g of NaOH in 200 mL of solution
(ii) 0.5 mol of KCl in 200 mL of solution
(iii) 40 g of NaOH in 100 mL of solution
(iv) 20 g of KOH in 200 mL of solution




………….
18
Which of the following terms are unit less? Molality, Molarity, Mole fraction, Mass percent
………….
19
The density of 3 molal solution of NaOH is 1.110 g mL–1. The molarity of the solution is…….

………….
20
Which of the following depends upon temperature? Molality, Molarity, Mole fraction, Mass percent

………….

Wednesday, 11 April 2018

Unit 1 : Solid Sate Question Bank


QUESTION BANK
CLASS XII
UNIT 1: SOLID STATE
ONE MARK QUESTIONS
Q.No.
QUESTION
1
How many unit cells constitute one unit cell of a face centered cubic crystal?
2
What type of semiconductor is obtained when silicon is doped with boron?
3
What type of magnetism is shown in the following alignment of magnetic moments?
↓↓↓↓↓↓↓↓↓↓
4
What type of stoichiometric defect is shown by AgCl?
5
What type of substances would make better permanent magnets: Ferromagnetic or Ferrimagnetic?
6
Why does presence of excess lithium make LiCl crystals pink?
7
A solid with cubic crystal is made of two elements P & Q. atoms of Q are at the corners of the cube and P at the centre. What is the formula of the compound?
8
What change occurs when AgCl is doped with CdCl2?
9
Calculate the number of atoms in a face centred cubic unit cell.
10
Which type ionic substance show Schottky defect in solids?
11
What is meant by “doping” in a semiconductor?
12
Write the point of distinction between metallic solid and ionic solid other than metallic lusture.
13
How may the conductivity of an intrinsic semiconductor be increased?
14
What type of stoichiometric defect is shown by AgBr and AgI?
15
Some of the glass objects recovered from ancient monuments look milky instead of being transparent. Why?
16
What type of defect arises when a solid is heated?
17
What is intrinsic semiconductors? Give one example
18
Why does LiCl acquire pink colour when heated in Li vapours?
19
Crystalline solids are “anisotropic in nature”. What does this statement mean?
20
Which stoichiometric defect in crystals increases the density of a solid?
21
What is the total number of atoms per unit cell in a face –centred (fcc) cubic structure?
22
What is the coordination number of each ion in a rock salt type structure?
23
Which point defect in a crystal does not alter the density of the relevant solid?
24
Which point defect in a crystals alters the density of the solid?
25
Which point defect decreases the density of a solid?
26
How do metallic & ionic substances differ in conducting electricity?
27
What type of interactions hold together the molecules in a polar molecular solid?
28
What type of semiconductor is obtained when silicon is doped with arsenic?
29
Give one example of ionic compound which shows Frenkel Defect.
30
Why glass is considered a super cooled liquid?
31
Solid A is a very hard electrical insulator in solid as well as in molten state and melts at extremely high temperature. What type of solid is it?
32
A compound is formed by two elements X and Y. Atoms of the element Y (as anions) make ccp and those of the element X (as cations) occupy all the octahedral voids. What is the formula of the compound?

33
Atoms of element B form hcp lattice and those of the element A occupy
2/3rd of tetrahedral voids. What is the formula of the compound formed by the elements A and B?
34
A compound is formed by two elements M and N. The element N forms ccp and atoms of M occupy 1/3rd of tetrahedral voids. What is the formula of the compound?

Ferric oxide crystallises in a hexagonal close-packed array of oxide  ions with  two  out  of  every  three  octahedral  holes  occupied  by  ferric  ions. Derive the formula of the ferric oxide.



2 MARKS QUESTIONS
Q.No.
QUESTION
1
Account for the following-
a.       Schottky defects lower the density of the related solid.
b.      Conductivity of silicon increases on doping it with phosphorous.
2
Aluminium crystallises in an fcc structure. Atomic radius of the metal is 125pm. What is the length of the side of the unit cell of the metal?
3
If NaCl is doped with 10-3mole% SrCl2, what will be the concentration of cationic vacancies (NA=6.02x1023)?
4
What is semiconductor? Describe two main types of semiconductors and contrast their mechanism.
5
A compound is forms hcp structure. What is the total number of voids in 0.5mol of it? How many of these are tetrahedral voids?
6
The unit cell of an element of atomic mass 108u and density 10.5gcm-3 is a cube with edge length 409pm. Find the type of unit cell of the crystal.
(Given: Avogadro’s number NA= 6.02x1023mol-1)
7
a.        
8
An element of X crystallises in fcc structure. 208g of it has 4.2832x1024 atoms. Calculate the edge of the unit cell, if density of X is 7.2gcm-3.
9
Calculate the packing efficiency of a metal crystal for a simple cubic lattice.
10
Explain the following terms with suitable example:
a.       Anti-ferromagnetism
b.      13-14 compounds
11
An alloy of gold and cadmium crystallises with a cubic structure in which gold atoms occupy the corners and cadmium atoms fit into the face centres. Assign formula for this alloy.
12
In terms of band theory, explain the differences between a conductor and a semiconductor and give one suitable example for each.
13
Calculate the packing efficiency of a ccp structure.
14
Explain the following terms with suitable example:
i.                    Schottky defect
ii.                  Interstitial defect
15
Chromium metal crystallises in a body centred cubic lattice. The length of the unit cell edge is found to be 287pm. Calculate the atomic radius of chromium.
16
The edge of face centred cubic unit cell of calcium is 556.5pm.  Calculate the radius of calcium atom.
17
What type of stoichiometric defect is shown by –
i.ZnS
ii.AgBr
18
What makes a glass different from a solid such as quartz? Under what conditions quartz could be converted into glass
19
If the radius of the octahedral void is r and radius of the atoms in close- packing is R, derive relation between r and R.         
20
Analysis shows that nickel oxide has the formula Ni0.98O1.00. What fractions of Ni exist as Ni2+ and Ni3+.

3MARKS QUESTIONS
Q.No.
QUESTION
1
Iron (II) oxide has a cubic structure and each unit cell has a size of 5A0. If density of this oxide is 4gmcm-3, calculate the number of Fe2+ and O2- ions present in each unit cell.
2
Niobium crystallises in body centred cubic structure. If density is 8.55gcm-3, calculate atomic radius of niobium, given its atomic mass 93u.
3
An element crystallises in a structure having fcc unit cell of edge 200pm. Calculate the density if 200g of this element contains 24x1023 atoms.
4
Tungsten crystallises in body centred cubic unit cell. If the edge of the unit cell is 316.5pm, what is the radius of tungsten atom?
5
Iron has body centred cubic unit cell with a cell dimension of 286.65pm. The density of iron is 7.874gcm-3. Use this information to calculate Avogadro’s number.
(At. Mass of Fe = 55.845u)
6
Copper crystallises with face centred cubic unit cell. If the radius of copper atom is 127.8pm, calculate the density of copper metal.
(At. Mass of Cu= 63.55u & Avogadro’s number NA= 6.02x1023mol-1)
7
What is the distance between Na+ & Cl- ions in NaCl crystal if its density is 2.165gcm-3?
(At. Mass of Na=23u, Cl=35.5u, Avogadro’s number NA= 6.02x1023mol-1)
8
Silver crystallises in face centred cubic unit cell. Each side of this unit cell has a length 409pm. Calculate the radius of the silver atom. (Assume that each face atom is touching the four corner atoms )
9
How will you account for the following:
i.                    Frenkel defects are not found in alkali metal halides
ii.                  Schottky defect lowers the density of related solids
iii.                Impurity doped silicon is a semiconductor.
10
Explain the following terms with suitable example:
a.       Ferromagnetism
b.      Ferrimagnetism
c.       Paramagnetism
11
Silver crystallises in a fcc lattice. The edge length of its unit cell is 4.077x10-8cm and its density is 10.5gcm-3. Calculate the atomic mass of silver.
(NA= 6.02x1023mol-1)
12
The well-known mineral fluorite is chemically calcium fluoride. It is known that in one unit cell of this mineral there are 4 Ca2+ ions and 8F- ions and that Ca2+ ions are arranged in a fcc lattice. The F- ions fill all the tetrahedral holes in the face centred cubic lattice of Ca2+ ions. The edge of the unit cell is 5.46x10-8cm in length. The density of the solid is 3.18g cm-3. Use this information to calculate Avogadro’s number (Molar mass of CaF2 = 78.08g mol-1)
13
Explain the following terms with suitable example:
i.                     Doping
ii.                   12-16 Compounds
iii.                 F-center