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PODAR INTERNATIONAL SCHOOL MEHSANA
Date:-22/6/2020 CH—CELL WORKSHEET 1
MCQS
1. Which of these options is not a function of Ribosomes?
(i) It helps in manufacture of protein molecules
(ii) It helps in manufacture of enzymes
(iii) It helps in manufacture of hormones
(iv) It helps in manufacture of starch molecules
(a) (i) and (ii)
(b) (ii) and (iii)
(c) (iii) and (iv)
(d) (iv) and (i)
2. Following are a few definitions of osmosis. Read carefully and select the correct definition
(a) Movement of water molecules from a region of higher concentration to a region of lower concentration through a semipermeable membrane
(b) Movement of solvent molecules from its higher concentration to lower concentration
(c) Movement of solvent molecules from higher concentration to lower concentration of solution through a permeable membrane
(d) Movement of solute molecules from lower concentration to a higher concentration of solution through a semipermeable membrane
3. Which of the following are covered by a single membrane?
(a) Mitochondria
(b) Vacuole
(c) Lysosome
(d) Plastid
4. Which cell organelle plays a crucial role in detoxifying many poisons and drugs in a cell?
(a) Golgi apparatus
(b) Lysosomes
(c) Smooth endoplasmic reticulum
(d) Vacuoles
5. The undefined nuclear region of prokaryotes are also known as
(a) nucleus
(b) nucleolus
(c) nucleic acid
(d) nucleoid
6. Which out of the following is not a function of vacuole?
(a) Storage
(b) Providing turgidity and rigidity to the cell
(c) Waste excretion
(d) Locomotion
Shorts questions
1. If you are provided with some vegetables to cook, you generally add salt to the vegetables during the cooking process. After adding salt, vegetables release water. What mechanism is responsible for this?
2. Write the name of different plant parts in which chromoplast, chloroplast and leucoplast are present.
3. Name the organelles which show the analogy written as under
(a) Transporting channels of the cell——
(b) Power house of the cell——
(c) Packaging and dispatching unit of the cell——
(d) Digestive bag of the cell——
(e) Storage sacs of the cell——
(f) Kitchen of the cell——
(g) Control room of the cell——
. What are the consequences of the following conditions?
(a) A cell containing higher water concentration than the surrounding medium
(b) A cell having low water concentration than the surrounding medium.
(c) A cell having equal water concentration to its surrounding medium.
6. Name the two organelles in a plant cell that contain their own genetic material and ribosomes.
7. Why are lysosomes also known as “scavengers of the cells”?
8.Why does the skin of your fingers shrink when you wash clothes for a long time?
Long answer questions
1. Differentiate between rough and smooth endoplasmic reticulum.
2.a)Name and draw a cell which does not have a well defined nuclear region.Label it.
b)Mention two ways by which a photosynthetic cell belonging to this group differs from a .cell of your body
PODAR INTERNATIONAL SCHOOL,MEHSANA
STD:-IX SUB:SCI(CHEM) CH:STRUCTURE OF ATOM
WORKSHEET
________________________________________________
1. An
atom has atomic 2. Name two elements with number 12,
what is its valency and name the element?
same number of protons and neutrons?
3. Name
the isotope used for treatment of cancer.
4. 
What does this symbol
represent?
What does this symbol
represent?
5. Draw
the atomic structure of (i) an atom with same number of sub-atomic particles,
(ii) an atom with same number of electrons in L and M shell.
6. What
is an octate? Why would atoms want to complete their octate?
7. Find
the valency of 
8. What
are nucleons? What is the name given to those atoms which have same number of
nucleons in it?
9. Give
the difference between three sub-atomic particles.
10. Give
the names of three atomic species of hydrogen.
Fill in the blanks:
1. According to Maharishi Kanad, the tiniest to tiny particle of a pure
substance is called _________.
2. An atom is the smallest unit of an element which takes part in a
_________.
3. Mass of an electron is 1/1837 times less than the mass of one atom
of__________.
4. The K-shell of any atom cannot have more than _________ electrons.
5. Isotopes are the atoms of ___________ element, having same atomic number
but different mass number.
6. An atom of an element has 11 protons 11 electrons and 12 neutrons. The
atomic mass of the atom is __________.
7. Almost all the mass of an atom is concentrated in a small region of
space called the _______.
8. The subatomic particle not present in a hydrogen atom is________.
9. Cathode ray are a beam of fast moving ______ .
10.
________and________ more or less
complexly make up the mass of an atom.
11.
The number of neutrons in the
neutrons in the neutrons of an atom can be calculated by _______ the atomic
number of _______its mass number.
12.
The isotopes of an element do not
differ in the number of _______ but do differ in the number of _______.
13.
The type of radiations, which are not
deflected in presence of electric or magnetic field are termed as rays.
14.
The penetrating power of B-rays
is_______ times more than a-rays.
15.
Synthetic elements are those which
are prepared by _________.
16.
The control rods in a nuclear reactor
are made up of _________.
17.
_______ are stored in deep mines
which are not in use.
18.
When an elements emits B-particle,
its mass number________.
19.
Y-rays are________ radiations.
20.
The difference between the actual
isotopic mass and the sum of masses of protons, neutrons and electrons is
called_________.
21.
_______ are the best bombarding
particles.
________ is used for the
treatment of leukaemiaPODAR INTERNATIONAL SCHOOL,MEHSANA
STD:IX SUB:SCI(CHEM) CH:STRUCTURE OF ATOM(NOTES)
______________________________________________________
Sub-atomic particles of atom includes
(a) Electrons – negatively charged with charge of
–1 and negligible mass.
(b) Protons – Positively charged with charge of +1
and mass is 1 u.
(c) Neutrons – Particles are with no charge and
mass of 1 u.
Thomson’s model of an atom
• Atom is electrically neutral
consisting of positively charged sphere with electrons embedded in it.
• If failed to explain the results
of experiments carried out by other scientists.
Bohr’s model of an atom
• An atom has a positively charged
nucleus and electrons revolve in permitted circular orbits with fixed radii and
energy.
• Bohr explained the drawback of
Rutherford’s model of an atom.
Rutherford’s model of an atom
• He performed the α-particle
scattering experiment and proposed that an atom is electrically neutral, with a
positively charged nucleus having protons and neutrons and negatively charged
electrons revolving around the nucleus.
Bohr-Bury scheme
• The number of electrons that can
be present in a given shell is 2n2, when ‘n’ is the number of shell.
• Maximum number of electrons in
the outermost orbit should not exceed 8.
Valency
• The combining capacity of the
atoms of an element is valency.
• Elements having 1, 2, 3, and 4
electrons in the valence shell, has valency equal to number of electrons.
• Elements having more than 4
electrons in the valence shell has valency equal to 8 minus the number of
valence electrons.
Atomic number and mass number
• Atomic number (z) is number of
protons in one atom of an element.
• Mass number (A) is the sum of
protons and neutrons present in the atom of the element.
• Notation for an atom
Isotopes
• Isotopes are the atoms of the
same element, having the some atomic number but different mass number.
• Isotopes are useful as nuclear
fuel, in medical field, in carbon dating, etc.
PODAR
INTERNATIONAL SCHOOL , MEHSANA
STD : IX CH- WORK ENEGRY AND
POWER SUB : PHYSICS
NUMERICALS
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Q.1 A rocket is moving up with a velocity v . If the velocity of this rocket is
suddenly tripled , what will be the
ratio of two kinetic energies ?
Q.2 Avinash can run with a speed of 8 m s-1 against
the frictional force of 10 N & Kapil
can move with a speed of 3m s-1 against the frictional force
of 25 N .Who is more powerful and why ?
Q.3 A boy is
moving on a straight road against a frictional force of 5N.After travelling a
distance of 1.5 km he forgot the correct path at a roundabout of radius 100 m .However,
he moves on that circular path for one and half cycle and then he moves forward
up to 2.0 km. Calculate the work done by him.
Q.4 Can any
object have mechanical energy even if its momentum is zero? Explain
Q.5 Can any
object have momentum even if its mechanical energy is zero? Explain.
Q.6 The
power of motor pump is 2 kW, How much water per minute the pump can raise to a
height at 10 m ?(Given g = 10 m s-2 )
Q.7 The
weight of a person on a planet A is about half that on the earth. He can jump up
to 0.4 m height on the surface of the earth . How high can he jump on the
planet A ?
Q.8 The Velocity of a body moving in a straight
line is increased by applying a constant force F , for some distance in the direction of the motion .
Prove that increase in the kinetic energy of the body is equal to the work done
by the force on the body.
Q.9 Is it possible that an object is in the
state of accelerated motion due to external force acting on it , but no work is
being done by the force . Explain it with an example.
Q.10 A ball
is dropped from a height of 10 m. If the energy of the ball reduces by 40%
after striking the ground, how much high can the ball bounce back? (g = 10 ms-2)
Q.11 If an
electric iron of 1200 W is used for 30 minutes every day, find electric energy
consumed in the month of April.
Q.12 An
automobile engine propels a 1000 kg car ( A ) along a leveled road at a speed
of 36 km h-1 , Find the power if the opening frictional force of 100
N . Now, suppose after travelling a distance of 200 m, this car collides with
another stationary car ( B ) of same mass and comes to rest . Let its engine
also stop at the same time. Now car (B) starts moving on the same level road
without getting its engine started. Find the speed of the car (B) just after
the collision.
Q.13 A girl having mass of 35 kg sits on a trolley
of mass 5 kg . The trolley is given an initial velocity of 4ms-1 by
applying a force.The trolley comes to rest after covering a distance of 16 m.
a) How much work is done on the trolley?
b) How much work is done by the girl?
Q.14 Four
men lift 250 kg box to a height of 1m and hold it without raising or lowering
it, (a) How much work is done by the men in lifting the box?
(b) How much
work do they do in just holding it?
(c) Why do
they get tired while holding it ? (g= 10 ms-2)
Q.15 What is
power? How do you differentiate kilowatt from kilowatt-hour? The Jog Falls in
Karnataka state are nearly 20 m in high. 2000 tonnes of water falls from it in
a minute. Calculate the equivalent power
if all this energy can be utilized? (g = 10 ms-2)
Q.16 How is
the power related to the speed at which a body can be lifted? How many
kilograms will a man working at the power of 100 W, be able to lift at constant
speed of 1 ms-1 vertically?(g=10ms-2)
Q.17 Define
watt. Express kilowatt in terms of joule per second. A 150 kg car engine
develops 500 W for each kg. What force does it exert in moving the car at a
speed of 20 ms-1?
Q.18 Compare
the power at which each of the following is moving upwards against the force of
gravity?
(given g =
10 ms -2 )
a) a butterfly of mass 1.0 g that flies
upward at a rate of 0.5 ms -1
02/12/2019
Diversity in living
organisms
Multiple choice questions
1. Find out incorrect sentence
(a) Protista includes unicellular eukaryotic organisms
(b) Whittaker considered cell structure, mode and source of
nutrition for classifying the organisms in five kingdoms
(c) Both Monera and Protista may be autotrophic and
heterotrophic
(d) Monerans have well defined nucleus
2. Which among the following has specialised tissue for
conduction of water?
(i) Thallophyta
(ii) Bryophyta
(iii) Pteridophyta
(iv) Gymnosperms
(a) (i) and (ii)
(b) (ii) and (iii)
(c) (iii) and (iv)
(d) (i) and (iv)
3. Which among the following produce seeds?
(a) Thallophyta
(b) Bryophyta
(c) Pteridophyta
(d) Gymnosperms
4. Which one is a true fish?
(a) Jellyfish
(b) Starfish
(c) Dogfish
(d) Silverfish
5. Which among the following is exclusively marine?
(a) Porifera
(b) Echinodermata
(c) Mollusca
(d) Pisces
6. Which among the following have open circulatory system?
(i) Arthropoda
(ii) Mollusca
(iii) Annelida
(iv) Coelenterata
(a) (i) and (ii)
(b) (iii) and (iv)
(c) (i) and (iii)
(d) (ii) and (iv)
7. In which group of animals, coelom is filled with blood?
(a) Arthropoda
(b) Annelida
(c) Nematoda
(d) Echinodermata
8. Elephantiasis is caused by
(a) Wuchereria
(b) Pinworm
(c) Planarians
(d) Liver flukes
9. Which one is the most striking or (common) character of
the vertebrates?
(a) Presence of notochord
(b) Presence of triploblastic condition
(c) Presence of gill pouches
(d) Presence of coelom
10. Which among the following have scales?
(i) Amphibians
(ii) Pisces
(iii) Reptiles
(iv) Mammals
(a) (i) and (iii)
(b) (iii) and (iv)
(c) (ii) and (iii)
(d) (i) and (ii)
11. Find out the false statement
(a) Aves are warm blooded, egg laying and have four
chambered heart
(b) Aves have feather covered body, fore limbs are modified
as wing and breathe through lungs
(c) Most of the mammals are viviparous
(d) Fishes, amphibians and reptiles are oviparouous
12. Pteridophyta does not have
(a) root
(b) stem
(c) flowers
(d) leaves
13. Identify a member of porifera
(a) Spongilla
(b) Euglena
(c) Penicillium
(d) Hydra
14. Which is not an aquatic animal?
(a) Hydra
(b) Jelly fish
(c) Corals
(d) Filaria
15. Amphibians do not have the following
(a) Three chambered heart
(b) Gills or lungs
(c) Scales
(d) Mucus glands
16. Organisms without nucleus and cell organelles belong to
(i) fungi
(ii) protista
(iii) cyano bacteria
(iv) archae bacteria
(a) (i) and (ii)
(b) (iii) and (iv)
(c) (i) and (iv)
(d) (ii) and (iii)
17. Which of the following is not a criterion for classification
of living organisms?
(a) Body design of the organism
(b) Ability to produce one’s own food
(c) Membrane bound nucleus and cell organelles
(d) Height of the plant
18. The feature that is not a characteristic of
protochordata?
(a) Presence of notochord
(b) Bilateral symmetry and coelom
(c) Jointed legs
(d) Presence of circulatory system
DIVERSITY IN LIVING ORGANISMS 51
19. The locomotory organs of Echinodermata are
(a) tube feet
(b) muscular feet
(c) jointed legs
(d) parapodia
20. Corals are
(a) Poriferans attached to some solid support
(b) Cnidarians, that are solitary living
(c) Poriferans present at the sea bed
(d) Cnidarians that live in colonies
21. Who introduced the system of scientific nomenclature of
organisms
(a) Robert Whittaker
(b) Carolus Linnaeus
(c) Robert Hooke
(d) Ernst Haeckel
22. Two chambered heart occurs in
(a) crocodiles
(b) fish
(c) aves
(d) amphibians
23. Skeleton is made entirely of cartilage in
(a) Sharks
(b) Tuna
(c) Rohu
(d) None of these
24. One of the following is not an Annelid
(a) Nereis
(b) Earthworm
(c) Leech
(d) Urchins
25. The book Systema Naturae was written by
(a) Linnaeus
(b) Haeckel
(c) Whittaker
(d) Robert Brown
26. Karl Von Linne was involved with which branch of
science?
(a) Morphology
(b) Taxonomy
(c) Physiology
(d) Medicine
27. Real organs are absent in
(a) Mollusca
(b) Coelenterata
(c) Arthropoda
(d) Echinodermata
28. Hard calcium carbonate structures are used as skeleton
by
(a) Echinodermata
(b) Protochordata
(c) Arthropoda
(d) Nematoda
29. Differentiation in segmental fashion occurs in
(a) Leech
(b) Starfish
(c) Snails
(d) Ascaris
30. In taxonomic hierarchy family comes between
(a) Class and Order
(b) Order and Genus
(c) Genus and Species
(d) Division and Class
31. 5-Kingdom classification has given by
(a) Morgan
(b) R. Whittaker
(c) Linnaeus
(d) Haeckel
32. Well defined nucleus is absent in
(a) blue green algae
(b) diatoms
(c) algae
(d) yeast
33. The ‘Origin of Species’ is written by
(a) Linnaeus
(b) Darwin
(c) Hackel
(d) Whittaker
34. Meena and Hari observed an animal in their garden. Hari
called it an insect while Meena said it was an earthworm. Choose the character
from the following which confirms that it is an insect.
(a) Bilateral symmetrical body
(b) Body with jointed legs
(c) Cylindrical body
(d) Body with little segmentation
35. Write true (T) or false (F)
(a) Whittaker proposed five kingdom classification.
(b) Monera is divided into Archaebacteria and Eubacteria.
(c) Starting from Class, Species comes before the Genus.
(d) Anabaena belongs to the kingdom Monera.
(e) Blue green algae belongs to the kingdom Protista.
(f) All prokaryotes are classified under Monera.
36. Fill in the blanks
(a) Fungi shows———mode of nutrition.
(b) Cell wall of fungi is made up of ———.
(c) Association between blue green algae and fungi is called
as———.
(d) Chemical nature of chitin is ———.
(e) ———has smallest number of organisms with maximum number
of similar characters
(f) Plants without well differentiated stem, root and leaf
are kept in ———.
(g) ———are called as amphibians of the plant kingdom.
37. You are provided with the seeds of gram, wheat, rice,
pumpkin, maize and pea. Classify them whether they are monocot or dicot.
38. Match items of column (A) with items of column (B)
(A) (B)
(a) Naked seed
(A) Angiosperms
(b) Covered seed
(B) Gymnosperms
(c) Flagella (C) Bryophytes
(d) Marchantia
(D) Euglena
(e) Marsilea (E) Thallophyta
(f) Cladophora (F) Pteridophyta
(g) Penicillium (G) Fungi
39. Match items of column (A) with items of column (B)
(A)
(B)
(a) Pore bearing animals (A) Arthropoda
(b) Diploblastic
(B) Coelenterata
(c) Metameric segmentation (C) Porifera
(d) Jointed legs (D) Echinodermata
(e) Soft bodied animals (E) Mollusca
(f) Spiny skinned animals (F) Annelida
40. Classify the following organisms based on the
absence/presence of truecoelom (i.e., acoelomate, pseudocoelomate and
coelomate)
Spongilla, Sea anemone, Planaria, Liver fluke Wuchereria,
PODAR INTERNATIONAL SCHOOL
SUB :- SCI STD : IX
CH :-
ATOMS AND MOLECULES
1.Define
polyatomic ion. Give one example.
2.What
is formula unit of mass? How is it different from molecular mass?
3.What
is Law of conservation of mass and Law of constant proportions?
4.What
is an ion? Explain the types of ion with examples.
5.Find
the molecular mass of H2O.
6.Define
the term valency. What is the valency for magnesium and copper?
7.What
is the difference between cation and anion?
8.What
is atomicity? What is the atomicity of phosphorus and nitrogen?
9.Find
the number of atoms in 0.5 mole of C atom.
10.Find
the mass of 1.5 mole of CO2 molecule.
11.Calculate
the formula unit mass of NaCl and CaCl2.
12.What
is the difference between molecules 2O and O2?
Question
1
State the law of mass conservation.Answer
Law of mass conservation states that, mass can neither be created nor destroyed in a chemical reaction or a physical transformation.Question 2
What do you understand by the law of constant proportion?Answer
According to the Law of constant proportion, a chemical compound always has its compounding elements in definite proportion by mass, irrespective of the source and the type of chemical reaction.Question 3.
Who was responsible for coining the term atom?Answer
In modern science, John Dalton widely used it and he can be said to be responsible for coining it, but a more factually correct answer would be a Greek philosopher who goes by the name of Lucretius.
Question 4
What is an atom?Answer
Atom is the smallest particle of matter which can take part in a chemical reaction.Question 5.
What is a molecule?Answer
A molecule is a group of atoms bonded together which represents the most fundamental unit of a chemical compound capable of taking part in a chemical reaction.Question 6
What is atomicity?Answer
Atomicity is the number of atoms in a molecule.Question 7
Define atomic mass unit.Answer
The Atomic mass unit is the sum of the atomic masses of all the atoms in a molecule.Question 8.
Define ion.Answer
An ion is an atom or a molecule with an electric charge (+ve or -ve), caused by gain or loss of a single or multiple electrons.Question 9
Provide a difference between cations and anions, along with an example for each.Answer
Cations are positively charged ions, e.g. Fe2+ whereas, anions are negatively charged ions, e.g. F–
Question 10
Define Avogadro’s constant.Answer
Avogadro’s Constant (6.022 x 1023) is the number of atoms of an element present in one mole of that element.
State the law of mass conservation.Answer
Law of mass conservation states that, mass can neither be created nor destroyed in a chemical reaction or a physical transformation.Question 2
What do you understand by the law of constant proportion?Answer
According to the Law of constant proportion, a chemical compound always has its compounding elements in definite proportion by mass, irrespective of the source and the type of chemical reaction.Question 3.
Who was responsible for coining the term atom?Answer
In modern science, John Dalton widely used it and he can be said to be responsible for coining it, but a more factually correct answer would be a Greek philosopher who goes by the name of Lucretius.
Question 4
What is an atom?Answer
Atom is the smallest particle of matter which can take part in a chemical reaction.Question 5.
What is a molecule?Answer
A molecule is a group of atoms bonded together which represents the most fundamental unit of a chemical compound capable of taking part in a chemical reaction.Question 6
What is atomicity?Answer
Atomicity is the number of atoms in a molecule.Question 7
Define atomic mass unit.Answer
The Atomic mass unit is the sum of the atomic masses of all the atoms in a molecule.Question 8.
Define ion.Answer
An ion is an atom or a molecule with an electric charge (+ve or -ve), caused by gain or loss of a single or multiple electrons.Question 9
Provide a difference between cations and anions, along with an example for each.Answer
Cations are positively charged ions, e.g. Fe2+ whereas, anions are negatively charged ions, e.g. F–
Question 10
Define Avogadro’s constant.Answer
Avogadro’s Constant (6.022 x 1023) is the number of atoms of an element present in one mole of that element.
Question
11
(a)Explain how atoms exist.
(b)What do you understand by atomicity?
(c) Explain polyatomic ions.Answer
(a) Atoms of most elements don’t exist independently they exist as molecules, for molecules are more stable. However, atoms of inert gasses are chemically unreactive and they exist independently. E.g. helium.
(b) Atomicity is the number of atoms in a molecule. E.g. The atomicity of H2O = 3.
(c) A polyatomic ion is an ion composed of multiple atoms acting as a single charged unit.
Question 12
Explain atomic mass and gram atomic mass. Why does mass have different expressions viz, ‘u’ and ‘gm’?Answer
Atomic mass is the unit in which the mass of an atom is expressed, where one atomic mass unit is 1/12ththe mass of a carbon-12 atom.
Gram atomic mass is the atomic mass of an element expressed in grams.
The mass of an atom or a molecule is expressed in ‘u’, whereas, the molar mass is expressed in ‘gm’.
Question 13
Define a mole. Give the importance of the mole.Answer
One mole of atoms, molecules, or particles is that amount of the particle(atoms, molecules and ions) whose mass is equal to that particle’s atomic or molecular mass in grams. 1 mole = 6.022 x 1023 particles of that substance.
Importance of a mole: -
(a)Explain how atoms exist.
(b)What do you understand by atomicity?
(c) Explain polyatomic ions.Answer
(a) Atoms of most elements don’t exist independently they exist as molecules, for molecules are more stable. However, atoms of inert gasses are chemically unreactive and they exist independently. E.g. helium.
(b) Atomicity is the number of atoms in a molecule. E.g. The atomicity of H2O = 3.
(c) A polyatomic ion is an ion composed of multiple atoms acting as a single charged unit.
Question 12
Explain atomic mass and gram atomic mass. Why does mass have different expressions viz, ‘u’ and ‘gm’?Answer
Atomic mass is the unit in which the mass of an atom is expressed, where one atomic mass unit is 1/12ththe mass of a carbon-12 atom.
Gram atomic mass is the atomic mass of an element expressed in grams.
The mass of an atom or a molecule is expressed in ‘u’, whereas, the molar mass is expressed in ‘gm’.
Question 13
Define a mole. Give the importance of the mole.Answer
One mole of atoms, molecules, or particles is that amount of the particle(atoms, molecules and ions) whose mass is equal to that particle’s atomic or molecular mass in grams. 1 mole = 6.022 x 1023 particles of that substance.
Importance of a mole: -
- Atoms and molecules are very small. So, it gets bothersome weighing them in grams and trying to count them. Mole concept, however, allows us to count atoms and molecules by weighing macroscopic amounts of materials.
- It gives us a universally accepted standard of mass.
- It provides a standard for reaction stoichiometry.
Question
14
How many molecules are present in 1 ml of water?Answer
we know that density of water is 1gm/ml.
Hence, 1 gm water will = 1 ml water.
Now, we have molecular mass of water H2O = 1x2 + 16 = 18 gm
18 gm of water contain 6.022 x 1023 molecules
1 gm of water will contain = (6.022 x 1023)/18 molecules = 0.33 x 1023 molecules
So, the no. of molecules of water in 1ml of water = 3.3 x 1022
Question 15.
Calculate the molecular mass of glucose, C 6H12 O6.
Answer
Molecular mass of C6H12 O6 = (12 x 6) + 12 + (16 x 6)
= 180u.
Question 16.
H2O is the formula for water. What information do you get from this formula?Ans.
How many molecules are present in 1 ml of water?Answer
we know that density of water is 1gm/ml.
Hence, 1 gm water will = 1 ml water.
Now, we have molecular mass of water H2O = 1x2 + 16 = 18 gm
18 gm of water contain 6.022 x 1023 molecules
1 gm of water will contain = (6.022 x 1023)/18 molecules = 0.33 x 1023 molecules
So, the no. of molecules of water in 1ml of water = 3.3 x 1022
Question 15.
Calculate the molecular mass of glucose, C 6H12 O6.
Answer
Molecular mass of C6H12 O6 = (12 x 6) + 12 + (16 x 6)
= 180u.
Question 16.
H2O is the formula for water. What information do you get from this formula?Ans.
- H2O represents water
- H2O is a single molecule of water
- H2O is a single mole of water. Thus, it contains 6.022 x 1023 molecules of water.
- H2O contains 2 atoms of hydrogen and 1 atom of oxygen.
- H2O has a molar mass of 18g
Question
17
What is the formula unit mass of CaCl2 and NaCl.
(Na = 23, Cl=35.5, Ca=40)Answer
Formula Unit Mass of NaCl = 23 + 35.5 = 58.5u
Formula Unit Mass of CaCl2= 40+(2 x 35.5)= 111u.Question 18
(i) Name the body which approves the nomenclature of elements and compounds.
(ii) The symbol of sodium is written as Na and not as S. Give reason.
(iii) Name one element which form diatomic and one which form tetra atomic molecules.Answer
(i) IUPAC (International Union of Pure and Applied Chemistry)
(ii) Latin name of sodium is Natrium. The first two letters (Na) of this name represents the symbol of sodium.
(iii) Oxygen forms diatomic molecules and phosphorus forms tetra atomic molecules.
Question 19
10.0 g CaCO3 on heating gave 4.4 g of CO2 and 5.6 g of CaO. Show that these observations are in agreement with law of conservation of mass. Answer
Mass of reactants: 10gm
ass of product = 4.4 + 5.6 = 10g
Since Mass of reactants is equal to Mass of products , therefore these observations are in agreement with law of conservation of mass.
Question 20
Why are Dalton's symbol not used in chemistry?Answer
Dalton was the first scientist to use the symbol for the name of the elements a specific sense but it was difficult to memorize and in uses so Dalton's symbol are not used in chemistryQuestion 21
What is the difference between 2O, O2 and O3.Answer
2O represents 2 atoms of oxygen, and it is not possible for it to exist independently.
O2 represents an oxygen molecule which has two constituent oxygen atoms.
O3 represents a single ozone molecule and it does exist independently.
Question 22
Find out
(1) the mass of a single oxygen atom
(2) the mass of a single oxygen molecule
(3) the mass of a mole of oxygen gas
(4) the mass of an oxygen ion
(5) the number of atoms in a mole of an oxygen molecule.Answer
(1) Mass of a single oxygen atom
1 mole of oxygen atom = 16gm =6.022 x 1023 atoms
Therefore, Mass of one oxygen atom = 16/6.022 x 1023 = 2.65 x 10-23 gm
(2) Mass of a single oxygen atom
1 molecule oxygen = O2 =2 x 16 = 32u
(3) Mass of a mole of oxygen gas
1 mole of oxygen = O2 = 2 x 16 =32u
(4) Mass of an oxygen ion = mass of an oxygen atom (since electrons have negligible mass)
(5) Number of atoms in a mole of oxygen molecule
We know, 1 mole of oxygen molecule, O2 = 6.022 x 1023 molecules.
1 molecule of O2= 2 atoms
Therefore in a mole of O2 , there are =6.022 x 1023 x 2 atoms
= 1.022 x 1024 atoms.
Question 23
What is the atomicity of oxygen and phosphorous?Answer
Atomicity of oxygen, O2= 2 and atomicity of phosphorous, P4= 4.
Question 24
How many moles of SO2 have same mass as 3 moles of oxygen?
Answer
mass of 3 moles of oxygen = 3 x 16 = 48g Now, mass of SO2 = 32 + 2 x16 = 64g as 64g of SO2 = 1 mole then 48 g of SO2 = (1/64)x 48 =0.75 mole
What is the formula unit mass of CaCl2 and NaCl.
(Na = 23, Cl=35.5, Ca=40)Answer
Formula Unit Mass of NaCl = 23 + 35.5 = 58.5u
Formula Unit Mass of CaCl2= 40+(2 x 35.5)= 111u.Question 18
(i) Name the body which approves the nomenclature of elements and compounds.
(ii) The symbol of sodium is written as Na and not as S. Give reason.
(iii) Name one element which form diatomic and one which form tetra atomic molecules.Answer
(i) IUPAC (International Union of Pure and Applied Chemistry)
(ii) Latin name of sodium is Natrium. The first two letters (Na) of this name represents the symbol of sodium.
(iii) Oxygen forms diatomic molecules and phosphorus forms tetra atomic molecules.
Question 19
10.0 g CaCO3 on heating gave 4.4 g of CO2 and 5.6 g of CaO. Show that these observations are in agreement with law of conservation of mass. Answer
Mass of reactants: 10gm
ass of product = 4.4 + 5.6 = 10g
Since Mass of reactants is equal to Mass of products , therefore these observations are in agreement with law of conservation of mass.
Question 20
Why are Dalton's symbol not used in chemistry?Answer
Dalton was the first scientist to use the symbol for the name of the elements a specific sense but it was difficult to memorize and in uses so Dalton's symbol are not used in chemistryQuestion 21
What is the difference between 2O, O2 and O3.Answer
2O represents 2 atoms of oxygen, and it is not possible for it to exist independently.
O2 represents an oxygen molecule which has two constituent oxygen atoms.
O3 represents a single ozone molecule and it does exist independently.
Question 22
Find out
(1) the mass of a single oxygen atom
(2) the mass of a single oxygen molecule
(3) the mass of a mole of oxygen gas
(4) the mass of an oxygen ion
(5) the number of atoms in a mole of an oxygen molecule.Answer
(1) Mass of a single oxygen atom
1 mole of oxygen atom = 16gm =6.022 x 1023 atoms
Therefore, Mass of one oxygen atom = 16/6.022 x 1023 = 2.65 x 10-23 gm
(2) Mass of a single oxygen atom
1 molecule oxygen = O2 =2 x 16 = 32u
(3) Mass of a mole of oxygen gas
1 mole of oxygen = O2 = 2 x 16 =32u
(4) Mass of an oxygen ion = mass of an oxygen atom (since electrons have negligible mass)
(5) Number of atoms in a mole of oxygen molecule
We know, 1 mole of oxygen molecule, O2 = 6.022 x 1023 molecules.
1 molecule of O2= 2 atoms
Therefore in a mole of O2 , there are =6.022 x 1023 x 2 atoms
= 1.022 x 1024 atoms.
Question 23
What is the atomicity of oxygen and phosphorous?Answer
Atomicity of oxygen, O2= 2 and atomicity of phosphorous, P4= 4.
Question 24
How many moles of SO2 have same mass as 3 moles of oxygen?
Answer
mass of 3 moles of oxygen = 3 x 16 = 48g Now, mass of SO2 = 32 + 2 x16 = 64g as 64g of SO2 = 1 mole then 48 g of SO2 = (1/64)x 48 =0.75 mole
MULTIPLE
QUESTIONS.
- Which of the following statements is not true about an atom?
- (a) Atoms are not able to exist independently
- (b) Atoms are the basic units from which molecules and ions are formed
- (c) Atoms are always neutral in nature
- (d) Atoms aggregate in large numbers to form the matter that we can see, feel or touch
- The chemical symbol for nitrogen gas is
- (a) Ni
- (b) N2
- (c) N+
- (d) N
- The chemical symbol for sodium is
- (a) So
- (b) Sd
- (c) NA
- (d) Na
- Which of the following would weigh the highest?
- (a) 0.2 mole of sucrose (C12H22O11)
- (b) 2 moles of CO2
- (c) 2 moles of CaCO3
- (d) 10 moles of H2O
- Which of the following has maximum number of atoms?
- (a) 18g of H2O
- (b) 18g of O2
- (c) 18g of CO2
- (d) 18g of CH4
- Which of the following contains maximum number of molecules?
- (a) 1g CO2
- (b) 1g N2
- (c) 1g H2
- (d) 1g CH4
- Mass of one atom of oxygen is
- 3.42 g of sucrose are dissolved in 18g of water in a beaker. The number of oxygen atoms in the solution are
- (a) 6.68 × 1023
- (b) 6.09 × 1022
- (c) 6.022 × 1023
- (d) 6.022 × 1021
- A change in the physical state can be brought about
- (a) only when energy is given to the system
- (b) only when energy is taken out from the system
- (c) when energy is either given to, or taken out from the system
- (d) without any energy change
Short
Answer Type Questions
- Which of the following represents a correct chemical formula? Name it.
- (a) CaCl
- (b) BiPO4
- (c) NaSO4
- (d) NaS
- Write the molecular formulae for the following compounds
- (a) Copper (II) bromide
- (b) Aluminium (III) nitrate
- (c) Calcium (II) phosphate
- (d) Iron (III) sulphide
- (e) Mercury (II) chloride
- (f) Magnesium (II) acetate
- Write the molecular formulae of all the compounds that can be formed by the combination of following ions
Cu2+, Na+, Fe3+, C1–, SO42-, PO43- - Write the cations and anions present (if any) in the following compounds
- (a) CH3COONa
- (b) NaCl
- (c) H2
- (d) NH4NO3
- Give the formulae of the compounds formed from the following sets of elements
- (a) Calcium and fluorine
- (b) Hydrogen and sulphur
- (c) Nitrogen and hydrogen
- (d) Carbon and chlorine
- (e) Sodium and oxygen
- (f) Carbon and oxygen
- Which of the following symbols of elements are incorrect? Give their correct symbols
- Give the chemical formulae for the following compounds and compute the ratio by mass of the combining elements in each one of them. (You may use appendix-III).
- (a) Ammonia
- (b) Carbon monoxide
- (c) Hydrogen chloride
- (d) Aluminium fluoride
- (e) Magnesium sulphide
- State the number of atoms present in each of the following chemical species
- (a) CO32–
- (b) PO33–
- (c) P2O5
- (d) CO
- What is the fraction of the mass of water due to neutrons?
- Does the solubility of a substance change with temperature? Explain with the help of an example.
- Classify each of the following on the basis of their atomicity.
- (a) F2
- (b) NO2
- (c) N2O
- (d) C2H6
- (e) P4
- (f) H2O2
- (g) P4O10
- (H) O3
- (i) HCl
- (j) CH4
- (k) He
- (l) Ag
- You are provided with a fine white coloured powder which is either sugar or salt. How would you identify it without tasting?
- Calculate the number of moles of magnesium present in a magnesium ribbon weighing 12 g. Molar atomic mass of magnesium is 24g mol–1.
