PAPER: SCIENCE MARKS:
20X4=80
Q.1
Draw a diagram to show open stomatal pore and label on it:
(i) guard cells
(ii) chloroplast
(b) State two functions of stomata.
(c) How do guard cells regulate the
opening and closing of stomatal pore?
Q.2
What is the difference between the manner in which movement
takes place in a sensitive plant and the movement in our legs? Explain the
involved terms.
Q.3
Write the chemical equation of the reaction in which the
following changes have taken place with an example of each:
(i) Change in colour
(ii) Change in temperature
(iii) Formation of precipitate
Q.4
The image formed by a concave mirror is observed to be
virtual, erect and larger than the object. Where should be the position of the
object? (a) Between the principal focus and the centre of curvature (b) At the
centre of curvature (c) Beyond the centre of curvature (d) Between the pole of
the mirror and its principal focus.
Q.5
State the chemical properties on which the following uses of
baking soda are based:
(i) as an antacid
(ii) as a soda acid fire extiguisher
(iii) to make bread and cake soft and
spongy.
Q.6
Draw a diagram of human excretory system and label all parts.
Q.7
One-half of a convex lens is covered with a black paper. Will
this lens produce a complete image of the object? Verify your answer
experimentally. Explain your observations.
Q.8
Write chemical equation reactions taking place when carried
out with the help of
(a) Iron reacts with steam
(b) Magnesium reacts with dil HCl
(c) Copper is heated in air.
Q.9
Define tropism and nastic movement. How it differ from
chemical coordination in palnt.
Q.10
(a) Write the name given to bases that are highly soluble in
water. Give an example.
(b) How is tooth decay related to pH?
How can it be prevented?
(c) Why does bee sting cause pain and
irritation? Rubbing of baking soda on the sting area gives relief.
Q.11
Why do herbivores have longer, small intestine than
carnivores? Also mention use of large and small intestine in digestion.
Q.12
(a) Write one example for each of decompostion reaction
carried out with help of (i) Electricity (ii) Heat (iii) Light
(b) Which of the following statements is
correct and why copper can displace silver from silver nitrate and silver can
displace copper from copper sulphate solution.
Q.13
Give reasons (a) Platinum, gold and silver are used to make
jewellery. (b) Sodium, potassium and lithium are stored under oil. (c)
Aluminium is a highly reactive metal, yet it is used to make utensils for
cooking. (d) Carbonate and sulphide ores are usually converted into oxides
during the process of extraction.
Q.14
State reason for the following statements:
(i) Tap water conducts electricity
whereas distilled water does not.
(ii) Dry hydrogen chloride gas does not
turn blue litmus red whereas dilute hydrochloric acid does.
(iii) During summer season, a milk man
usually adds a very small amount of baking soda to fresh milk.
(iv) For a dilution of acid, acid is
added into water and not water into acid.
(v) Ammonia is a base but does not
contain hydroxyl group.
Q.15
Draw a diagram of human respiratory system and label all
parts.
Q.16
Describe an activity to observe what happens when quick lime
is added to water taken in a beaker. State two important observations and name
the type of reaction taking place.
Q.17
(a) Name the site of
exchange of material between the blood and surrounding cells. (b) Draw a
schematic representation of transport and exchange of oxygen and carbon dioxide
in human body.
Q.18
Explain why is hydrochloric acid a strong acid and acetic
acid, a weak acid. How can it be verified?
(ii) Explain why aqueous solution of an
acid conducts electricity.
(iii) You have four solutions A, B, C
and D. The pH of solution A is 6, B is 9, C is 12 and D is 7,
(a) Identify the most acidic and most
basic solutions.
(b) Arrange the above four solutions in
the increasing order of H+ ion concentration.
(c) State the change in colour of pH
paper on dipping in solution C and D.
Q.19
.(i) Write a balanced chemical equation for process of
photosynthesis.
(ii)When do desert plants
take up carbon dioxide and perform photosynthesis?
Q.20
What is redox reaction? Identify the substance oxidised and
the substance reduced in the following reactions.
(i)2PbO + C —–> 2Pb + CO2
(ii)MnO2 + 4HCl —–>
MnCl2 + 2H20 + Cl2
Q.21
(a)What is the role of HCl in our stomach ?
(b) What is emulsification of fats ?
(c) Which protein digesting enzyme is
present in pancreatic juice ?
Q.22
Draw diagram of human brain with function of
its parts.
Q.23
Write pH and how it differs from others
indicators.
Q.24
Define artificial kidney and draw its diagram
with explanation of working.
Q.25
What is corrosion and give activity for the
factor causing corrosion. Mention method to control it.
+
No comments:
Post a Comment