Friday 31 July 2015
Saturday 18 July 2015
CLASS - X (Chemical Reactions and equations) work sheet-1
1. Take about 5 ml of dil. HCl in a test tube and add a few pieces of fine granules to it. Which gas is evolved?
(a) Chlorine
(b) Hydrogen
(c) HCl
(d) Nitrogen
2. Dissolving suger is an example of-
(a) Physical change
(b) Chemical change
(c) Redox Reaction
(d) None of these.
3. Heat is evolved diving
(a) Endothermic Reaction
(b) Displacement Reaction
(c) Combustion Reaction
(d) Combination Reaction
4. Which of the following is not a balanced equation?
(a) Fe +Cl2 ----------FeCl3
(b) Mg + CuSO4 ------------ MgSO4 + C
(c) NaOH + 2HCl ---------------- NaCl + H2 O
(d) Zn + S ----------- ZnS
5. The reaction between lead nitrate and potassium iodide present in aqueous solutions is an example of
(a) Decomposition Reaction
(b) Displacement Reaction
(c) Double Displacement Reaction
(d) Neutralisation Reaction
6. Why is a Combustion reaction an oxidation reaction?
7. Why cannot a chemical change be normally reversed?
8. Identify the substance oxidized and reduced in the reaction.
CuO(s) + Zn(s)---------------- ZnO(s) +Cu(s)
9. When you mix solutions of lead (II) nitrate and potassium iodide,
(a) What is the colour of the precipitate formed? Name the compound evolved?
(b) Write a balanced chemical reaction?
(c) Is this a double displacement reaction?
11. Transfer the following into chemical equations and balance them.
(1) Hydrogen gas combines with nitrogen to from ammonia.
(2) Hydrogen sulphide gas burns in air to give water and sulphurdioxide.
(3) Potassium metal reacts with water to give potassium hydroxide and
hydrogen gas.
12. Balance the equations
(1) HNO3 +Ca(OH)2 ------------- Ca(NO3 )2 + H 2O
(2) NaCl + AgNO3 ------------------ AgCl + NaNO3
(3) BaCl2 + H2SO4-------------- BaSO4 + HCl
13. Write three equations for decomposition reaction where energy is supplied in the form of heat, light and electricity?
14. With the help of an activity show that iron is more reactive than copper?
CLASS – X Science (Acid, Base and Salt) WORK SHEET-2
1. The H+ ion concentration of a solution is1.0 X 10-5M. The solution is
(a) Acidic (b) Alkaline (c) Neutral (d) Amphoteric
2. An aqueous solution with pH-zero is
(a) Acidic (b) Alkaline (c) Neutral (d) Amphoteric
3. Setting of Plaster of Paris takes place due to
(a) Oxidation (b) Reduction (c) Dehydration (d) Hydration
4. The difference of water molecules is gypsum and Plaster of Paris is
(a) 5/2 (b) 2 (c) 1/2 (d) 3/2
5. The odour of acetic acid resembles that of
(a) Rose (b) Burning Plastic (c) Vinegar (d) Kerosene
6. Give the name and formula of two
(i) strong monobasic acids (ii) two weak dibasic acids
7. Why alkalis like sodium hydroxide and potassium hydroxide should not be left exposed to air?
8. Dry ammonia has no action on litmus paper but a solution of ammonia in water turns red litmus paper blue. Why is it so?
9. Bleaching powder forms a milky solution in water. Explain.
10. A first aid manual suggests that vinegar should be used to treat wasp sting and balking soda for bee stings.
(a) What does this information tell you about the chemical name of the wasp
sting?
(b) If there were no baking soda in the house, what other house hold substances
would you use to treat as stings?
11. Does Tartaric acid helps in making cake or bread fluffy. Justify.
12. Explain why?
(a) Common salt becomes sticky during the rainy season.
(b) Blue vittriol change to white upon heating.
13. A compound X of sodium is commonly used in kitchen for making crispy pakoras. It is also used for curing acidity in the stomach. Identify ‘X’. What is its chemical formula? State the reaction that takes places when it is heated during cooking?
14. (a) Why does an aqueous solution of acid conduct electricity?
(b) How does the concentration of hydrogen ions [ H3 O] + changes when the solution of an acid is diluted with water?
(c) Which has higher pH. A concentrated or dilute solution of HCl?
(d) What would you observe on adding dil HCl acid to (i) Sodium bicarbonate placed in a test tube. (ii) Zinc metal in a test tube.
CLASS - X (Acid Base and Salt) work sheet-1
1. Washing soda has the formula
(a) Na2CO3.7H2O (b) Na 2CO3 .10H2 O (c) Na2 CO3 .H2 O (d) Na 2CO3
2. Plaster of Paris hardens by
(a)Giving off CO2 (b)Changing into CaCO3 (c) Combining with water (d) Giving out water
3. Which of the following is evolved when Na 2CO3 is heated?
(a) CO2 (b) CO (c) O2 (d) NO
4. A drop of liquid sample was put on the pH paper, paper turned blue. The liquid
sample must be of
(a) Lemon Juice
(b) HCl
(c) Sodium bicarbonate
(d) Ethanoic acid.
5. If pH of solution is 13, it means that if is
(a) Weakly acidic (b) Weakly basic (c) Strongly acidic (d) Strongly Basic
6. Why does not an acid show any acidic behavior is the absence of water?
7. Fresh milk has a pH of 6. What will be the PH value if milk changes into a curd Justify.
8. What is the reaction between hydrogen in concentration ion concentration of an aqueous solution and pH?
9. How will you show that acetic acid is monobasic acid
Friday 17 July 2015
CLASS - XI CHEMISTRY (Structure of Atom) work sheet-6
Topic:- Orbital’s and Quantum Numbers
1. Which orbital is non – directional?2. What is the meaning of quantization of energy?
3. Why is energy of 1s electron lower than 2s electron?
4. Which quantum number determines
(i) energy of electron (ii) Orientation of orbitals.
5. What is nodal surface or nodes?
6. How many spherical nodal surfaces are there in 4s – sub-shell?
7. Arrange the electrons represented by the following sets of quantem number
in decreasing order of energy.
1. n = 4, l = 0, m = 0, s = +1/2
2. n = 3, l = 1, m = 1, s = -1/2
3. n = 3, l = 2, m = 0, s = +1/2
4. n = 3, l = 0, m = 0, s = -1/2
8. What designations are given to the orbitals having
(i) n = 2, l = 1 (ii) n = 2, l = 0 (iii) n = 4, l = 3
(iv) n = 4, l = 2 (v) n = 4, l = 1?
9. Write the electronic configuration of (i) Mn4+, (ii) Fe3+ (iii) Cr2+ and Zn2+
Mention the number of unpaired electrons in each case.
CLASS - XI CHEMISTRY (Structure of Atom) work sheet-5
Topic:-Quantum Mechanical Model of the Atom
1. States Heisenberg’s Uncertainty Principle.2. Give the mathematical expression of uncertainty principle.
3. How would the velocity be effected if the position is known?
4. We do not see a car moving as a wave on the road why?
5. Give the de – Broglie’s relation.
6. Why cannot the motion of an electron around the nucleus be determined accurately?
7. Calculate the uncertainty in the velocity of a wagon of mass 4000kg whose position is known accurately of ±10m
CLASS - XI CHEMISTRY (Structure of Atom) work sheet-4
Topic:-Photoelectric Effect
1. Define photoelectric effect.
2. How does the intensity of light effect photoelectrons?
3. What is threshold frequency?
4. Name the scientist who demonstrated photoelectric effect experiment.
5. What did Einstein explain about photoelectric effect?
6. What is the relation between kinetic energy and frequency of the photoelectrons?
7. Calculate energy of 2mole of photons of radiation whose frequency is 5´1014Hz.
8. What is emission and absorption spectra?
9. What transition in the hydrogen spectrum would have the same
wavelength as the Balmer transition, n = 4 to n = 2 of He+ spectrum?
10. Spectral lines are regarded as the finger prints of the elements. Why?
CLASS - XI CHEMISTRY (Structure of Atom) work sheet-3
Topic:-Bohr’s Model of an atom
1. Give the range of wavelength of the visible spectrum.2. State the two developments that led to the formation of Bohr’s model of atom.
3. What is an electromagnetic radiation?
4. Calculate the wavelength corresponding to a frequency of 98.8MHz.
5. Define black body radiation.
6. Define quantum.
7. Give the relation of energy (E) and frequency (v) as given by Planck.
8. Calculate the frequency and energy of a photon of radiation having
wavelength 3000A
9. What did Planck’s theory explain?
10. On what frequency does the frequency from a black body depend?
CLASS - XI CHEMISTRY (Structure of Atom) work sheet-2
Topic:-Atomic Models
1. Name the scientist who first gave the atomic model.2. What is an isotope?
3. What are isobars?
4. What are isotones?
5. What is an atomic number?
6. What is a mass number?
7. Find out atomic number, mass number, number of electron and
neutron in an element 4 0 2 0 ´ ?
8. Give the main features of Thomson’s Model for an atom.
9. Give the drawbacks of J.J. Thomson’s experiment.
10. What did Rutherford conclude from the observations of a - ray
scattering experiment?
11. Why Rutherford’s model could not explain the stability of an atom?
CLASS - XI CHEMISTRY (Structure of Atom) work sheet-1
Topic:-Discovery of Sub – Atomic Particles
1. Name the sub – atomic particles of an atom.2. Name the scientist who first formulated the atomic structure.
3. What is the e/m ratio of an electron?
4. What is the charge (e) of an electron?
5. What is the mass (m) of an electron?
6. (i) What is the mass of a proton?
(ii) What is the charge of a proton?
7. (i) What is the mass of a neutron?
(ii) What is the charge of a neutron?
8. Which experiment led to the discovery of electrons and how?
9. Give the main properties of canal ray experiment.
CLASS - XI CHEMISTRY (Classification of Elements and Periodicity in Properties) work sheet-5
Topic: - Miscellaneous Questions
1. What is the general outer electronic configuration of f – block elements?2. Why do Na and K have similar properties?
3. Arrange the following elements in the increasing order of metallic character :
Si, Be, Mg, Na, P.
4. The atomic number of an element is 16. Determine its position in accordance
to its electronic configuration.
5. Why are elements at the extreme left and extreme right the most reactive?
6. Why does the ionization enthalpy gradually decreases in a group?
7. Why does electronegativity value increases across a period and decreases
down period?
8. How does electronegativity and non – metallic character related to each
other?
CLASS - XI CHEMISTRY (Classification of Elements and Periodicity in Properties) work sheet-4
Topic: - Chemical Properties of element
1. Define valency.2. How does valency vary in a group and period in the periodic table?
3. What is the valency of noble gases?
4. How do metals react in a period?
5. How do metals react in a group?
6. How does the reactivity of non–metals changes in a period and group?
7. Give the properties of the oxides in a particular period.
8. What is an amphoteric oxide?
9. Define a neutral oxide.
10. Why does lithium form covalent bond unlike other alkali which forms ionic bond?
CLASS - XI CHEMISTRY (Classification of Elements and Periodicity in Properties) work sheet-3
Topic: - Trends in physical properties of elements
1. Predict the position of the element in the periodic table satisfying theelectronic configuration (n-1) d1 ns2 for n=4,
2. How does atomic size change in a group?
3. Why Li and Mg show resemblance in chemical behaivour?
4. The atomic radius of elements decreases along the period but Neon has highest
size among III period element? Why
5. Explain why cations are smaller and anions are larger in radii than their parent
atom?
6. Define ionization enthalpy and electron gain enthalpy?
7. How does atomic size change in a group?
8. The size of an atom can be expressed by three radii. Name them. Which of
these given the highest, and the lowest value of the atomic radius of an element?
9. Among the elements B, Al, C and Si
(a) Which has the highest first ionization enthalpy?
(b) Which has the largest atomic radius?
8. Na+ has higher value of ionization enthalpy than Ne, though both have same
electronic configuration.
CLASS - XI CHEMISTRY (Classification of Elements and Periodicity in Properties) work sheet-2
Topic: - Modern Periodic law and Nomenclature
1. Give the general characteristics of the long form of Modern periodic table?2. In short give the features of the seven periods.
3. Define electronic configuration.
4. What is the electronic configuration when elements are classified group
wise?
5. Give the main features of s-block elements.
6. Give the main features of p-block elements.
7. Give the main features of d-block elements.
8. Give the main features of f-block elements.
CLASS - XI CHEMISTRY (Classification of Elements and Periodicity in Properties) work sheet -1
Topic: - Genesis of Periodic classification
1. How many elements are known at present?2. Who was the first scientist to classify elements according to their properties?
3. What is the basis of triad formation of elements?
4. Stale the modern ‘Periodic law’?
5. Define and state Mendeleev’s periodic law.
6. How did Mendeleev arrange the elements?
7. Name the two elements whose existence and properties were predicted by
Mendeleev though they did not exist then.
8. Describe the main features of Mendeleev’s periodic table?
CLASS - IX Science (Matter in our surrounding) work sheet
1. If you decrease the surface area and increase the temperature, then the rate of
evaporation
(a) increase (b) decrease (c) remain same
(d) may increase or decrease depending upon other factors
2. 300k will have its corresponding temperature in degree centigrade as:-
(a) 30 c (b) 300 c (c) 27 c (d) 673 c
3. Liquid to gas and gas to liquid changes are called:-
(a) vaporization and condensation (b) condensation and vaporization
(c) sublimation and condensation (d) condensation and sublimation
4. Physical state of water at 25 c, 0 c and 100 c is respectively
(a) liquid, solid and gas (b) solid, liquid and gas
(c) solid, gas and liquid (d) gas, solid and liquid
5. What happens when the temperature of the solids increase?
6. When heat is being supplied to a solid, then what does the heat energy do to the
particles of solid?
7. Why is it that on increasing the wind speed the rate of evaporation increases?
8. Why do we say that evaporation is a surface phenomenon?
9. What is the state of inter particle distance inside a solid, liquid and gas?
10. Why it is that to smell cold food, we have to go close but smell of hot food
reaches us several meters away?
11. Why is it that a wooden chair should be called a solid and not a liquid?
12. Give an experiment to show that ammonium chloride undergoes sublimation.
Subscribe to:
Posts (Atom)