Model Test Paper മാതൃകാ ചോദ്യപേപ്പർ
A full paper in the Kerala Class 9 Chemistry pattern, covering the whole of “Non-metals” – preparing and testing hydrogen, oxygen and carbon dioxide, completing and balancing equations, the allotropes of carbon and why their structures give their properties, carbon dioxide and carbon monoxide, the tests for carbonates and chlorides, lightning, nitrogen fixation and fertilisers, ozone and CFCs, chlorine and bleaching, and reading calorific values from a chart. Work on paper with a timer before you look at the solutions.
Standard IX · Chemistry
Chapter 7 · അലോഹങ്ങൾ · Non-metals
- The first 15 minutes are cool-off time: read every question and plan your answers; do not write.
- Answer all questions. Marks for each question are shown on the right.
- Write every equation with correct formulas and balance it. Show every step in calculations, with units (g, kJ).
- Calorific value means the heat (kJ) released when 1 g of a fuel burns completely.
SECTION AAnswer all · 8 × 1 = 8 marks
1.
Which of these is the test for oxygen?
(1)(a) clear lime water turns milky(b) the gas burns with a “pop” at a burning splinter(c) a glowing splinter bursts into flame(d) a moist coloured cloth loses its colour
2.
Different forms of the same element that have different physical properties are called .
(1)3.
Find the relation and fill in: washing soda : Na2CO3·10H2O :: baking soda :
(1)4.
Nitrogen does not react easily at ordinary conditions because
(1)(a) it is lighter than air(b) its molecule has a strong triple bond(c) it is colourless and odourless(d) it makes up 78 % of air
5.
Pick the odd one out and give the reason: diamond, graphite, lamp black, fullerene
(1)6.
The most abundant element in the Earth’s crust is
(1)(a) hydrogen(b) nitrogen(c) oxygen(d) carbon
7.
Compounds of chlorine, fluorine and carbon that once were used in refrigerators and ACs, and that damage the ozone layer, are called .
(1)8.
Carbogen (കാർബൊജൻ), used for artificial respiration, is a mixture of
(1)(a) 95 % O2 and 5 % CO2(b) 95 % CO2 and 5 % O2(c) 78 % N2 and 22 % O2(d) CO and H2
SECTION BAnswer all · 5 × 2 = 10 marks
9.
Complete and balance: (a) Zn + HCl → ZnCl2 +
(b) H2 + Cl2 → (in sunlight). Name the type of reaction in (b).
(2)(b) H2 + Cl2 → (in sunlight). Name the type of reaction in (b).
10.
Hydrogen is made in industry by passing electricity through water. (a) Write the balanced equation for the electrolysis of water.
(b) Give one use of each gas formed.
(2)(b) Give one use of each gas formed.
11.
(a) How does the ozone layer in the stratosphere protect living things?
(b) How do CFCs damage it? Name one substitute used in new refrigerators.
(2)(b) How do CFCs damage it? Name one substitute used in new refrigerators.
12.
During a monsoon thunderstorm, lightning makes the nitrogen and oxygen of air combine. (a) Complete: N2 + O2 → ; 2NO + O2 →
(b) How do these products finally help the paddy fields?
(2)(b) How do these products finally help the paddy fields?
13.
Give reasons: (a) Hydrogen-filled balloons at a temple festival rise up, but sellers must keep them away from flames.
(b) Nitrogen in air is said to help control combustion.
(2)(b) Nitrogen in air is said to help control combustion.
SECTION CAnswer all · 4 × 3 = 12 marks
14.
The graph shows the calorific values (kJ/g) of some fuels (Fig 7.2). (a) Which fuel releases the most heat per gram, and which the least?
(b) How much heat is released when 2 g of hydrogen and 2 g of methane burn completely? How much more does hydrogen give?
(c) A scooter needs 480 kJ for a short trip. How many grams of petrol would give this heat? How many grams of ethanol?
(3)(b) How much heat is released when 2 g of hydrogen and 2 g of methane burn completely? How much more does hydrogen give?
(c) A scooter needs 480 kJ for a short trip. How many grams of petrol would give this heat? How many grams of ethanol?
15.
Figures A and B show how the carbon atoms are joined in two allotropes of carbon. (a) Identify A and B. To how many other carbon atoms is each carbon joined in each?
(b) Explain from the structure why diamond is used to cut glass but graphite is used as a lubricant.
(c) Equal masses of diamond and graphite, burnt in oxygen, give only carbon dioxide. What does this show? Write the equation.
(3)(b) Explain from the structure why diamond is used to cut glass but graphite is used as a lubricant.
(c) Equal masses of diamond and graphite, burnt in oxygen, give only carbon dioxide. What does this show? Write the equation.
16.
Three gas jars P, Q and R contain hydrogen, oxygen and carbon dioxide, but they are not labelled. The tests and results are given.
(a) Identify P, Q and R.
(b) Write the balanced equation for preparing the gas in Q in the laboratory from potassium permanganate.
(c) Jars of two of these gases are kept with the mouth up, but the jar of one gas is kept mouth down. Which one, and why?
(3)| Jar | Test | What is seen |
|---|---|---|
| P | a burning splinter is brought to the mouth | the gas burns with a “pop” sound |
| Q | a glowing splinter is put in | the splinter bursts into flame |
| R | the gas is shaken with clear lime water | the lime water turns milky |
(b) Write the balanced equation for preparing the gas in Q in the laboratory from potassium permanganate.
(c) Jars of two of these gases are kept with the mouth up, but the jar of one gas is kept mouth down. Which one, and why?
17.
(a) A family slept in a closed room with a charcoal stove burning. Name the poisonous gas that may form, write the equation for its formation, and say why it is dangerous.
(b) Which two properties of carbon dioxide make it useful in fire extinguishers?
(c) The solution of a white powder X gives a white precipitate with barium chloride solution; the precipitate dissolves in dilute hydrochloric acid with effervescence. What kind of salt is X? Give one example used at home.
(3)(b) Which two properties of carbon dioxide make it useful in fire extinguishers?
(c) The solution of a white powder X gives a white precipitate with barium chloride solution; the precipitate dissolves in dilute hydrochloric acid with effervescence. What kind of salt is X? Give one example used at home.
SECTION DAnswer all · 2 × 5 = 10 marks
18.
Read the passage and answer the questions.
(b) Name the gas that gives the smell. Write two of its physical properties.
(c) Write the equations that show how chlorine and water give nascent oxygen. How does nascent oxygen remove the colour of the cloth?
(d) The silver nitrate gave a curdy white precipitate that dissolved in ammonium hydroxide. What does this show? Write the equation, taking sodium chloride as the salt.
(e) In the laboratory, chlorine from potassium permanganate and concentrated hydrochloric acid is collected by upward displacement of air, inside a fume cupboard. Give a reason for each.
(5)After the August 2018 floods, the wells of many homes near Chengannur and Aluva were filled with muddy flood water. Health workers asked families to clean out the wells and then add bleaching powder. Near the treated wells there was a strong, pungent smell. A coloured cloth soaked in a strong bleaching-powder solution slowly lost its colour. At the school laboratory the teacher added silver nitrate solution to a sample of the well water.
(a) Bleaching powder is made by passing dry chlorine over dry slaked lime. Write the balanced equation.(b) Name the gas that gives the smell. Write two of its physical properties.
(c) Write the equations that show how chlorine and water give nascent oxygen. How does nascent oxygen remove the colour of the cloth?
(d) The silver nitrate gave a curdy white precipitate that dissolved in ammonium hydroxide. What does this show? Write the equation, taking sodium chloride as the salt.
(e) In the laboratory, chlorine from potassium permanganate and concentrated hydrochloric acid is collected by upward displacement of air, inside a fume cupboard. Give a reason for each.
19.
Read the passage and answer the questions.
(b) Nitrogen needs special conditions in the factory before it reacts. Why does it not react easily?
(c) How does growing payar add nitrogen to the soil of the field?
(d) Give one merit and one limitation each of organic manure and chemical fertiliser. What is the best practice for Ramettan?
(e) Why is nitrogen used to fill tyres and snack packets?
(5)FACT (The Fertilisers and Chemicals Travancore Ltd) at Udyogamandal near Kochi makes ammonia by combining nitrogen with hydrogen, and from it nitrogenous fertilisers for Kerala’s farms. Ramettan, a paddy farmer in Palakkad, uses this fertiliser and also cow-dung manure, and after the harvest he sows payar (green gram) in the same field. His son works at a tyre shop that fills tyres with nitrogen, and the snack packets in the shop are also filled with nitrogen.
(a) Write the balanced equation for making ammonia. From where does the factory get its nitrogen?(b) Nitrogen needs special conditions in the factory before it reacts. Why does it not react easily?
(c) How does growing payar add nitrogen to the soil of the field?
(d) Give one merit and one limitation each of organic manure and chemical fertiliser. What is the best practice for Ramettan?
(e) Why is nitrogen used to fill tyres and snack packets?
*** End of the question paper ***