Annual Examination – Set 1 വാർഷിക പരീക്ഷ
A full annual-examination paper covering all eight chapters (Part 1 and Part 2). Print it on A4 paper and give it to the student with a timer; the answer key is printed separately.
ANNUAL EXAMINATION · MODEL PAPER · SET 1
Standard IX · CHEMISTRY രസതന്ത്രം
Name:Roll No.:Division:
- The first 15 minutes is cool-off time. Use it to read the questions and plan your answers; do not write during this time.
- Answer all the questions. The score for each question is shown in brackets on the right.
- Read each question carefully before you answer. Answer in keeping with the score and the time.
- Write balanced chemical equations and correct formulae. Show the steps for calculations (mass, mass percentage, oxidation number).
- Draw neat, labelled diagrams wherever needed. Use the data (atomic numbers, masses, electronegativities) given in the questions.
Section AAnswer all questions · 10 × 1 = 10 marks
1.
In Rutherford’s gold foil experiment, most of the α particles passed straight through the gold foil without being deflected. From this observation Rutherford concluded that
[1](a) the nucleus is positively charged(b) most of the space inside an atom is empty(c) electrons revolve only in fixed orbits(d) the atom is a positive sphere with electrons embedded in it
2.
When a magnesium atom (2, 8, 2) changes into a magnesium ion, which of these does not change?
[1](a) the number of electrons(b) the number of protons(c) the charge(d) the electron configuration
3.
The energy needed to remove the most loosely bound electron from the outermost shell of an isolated gaseous atom is called .
[1]4.
In the reaction 4Na + O2 → 2Na2O, the substance that is reduced is
[1](a) sodium(b) oxygen(c) sodium oxide(d) both sodium and oxygen
5.
A candle is burnt on an open electronic balance. The reading slowly decreases. This is because
[1](a) mass is destroyed when the candle burns(b) the gases formed – carbon dioxide and water vapour – escape into the air(c) the melted wax becomes lighter(d) the law of conservation of mass does not apply to burning
6.
In the Haber process for making ammonia, N2(g) + 3H2(g) ⇌ 2NH3(g), the catalyst used is
[1](a) manganese dioxide(b) vanadium pentoxide(c) iron(d) amylase
7.
Enamel paint on a brush does not wash off with water, but it comes off easily in turpentine. The reason is
[1](a) turpentine is heavier than water(b) like dissolves like – non-polar paint dissolves in the non-polar solvent turpentine(c) water is a non-polar solvent(d) the paint reacts chemically with turpentine
8.
A 916 gold ornament has 916 g of gold in every 1000 g; the rest is silver and copper. In this solid solution, the solvent is .
[1]9.
Which of these is a saturated hydrocarbon?
[1](a) C3H4(b) C4H10(c) C2H2(d) C2H4
10.
Find the relation and fill in: CH3–CH3 : ethane :: CH2=CH–CH3 :
[1]Section BAnswer all questions · 8 × 2 = 16 marks
11.
An atom of an element X has mass number 19 and has 10 neutrons in its nucleus. (a) Find its atomic number and the number of electrons in it. (b) Write its electron configuration. How many electrons are there in its outermost shell?
[2]12.
(a) State Mendeleev’s periodic law and the modern periodic law. (b) Chlorine has two isotopes, 35
17Cl and 37
17Cl. Why would they be a problem in a table arranged by atomic mass, but not in the modern periodic table?
[2]17Cl and 37
17Cl. Why would they be a problem in a table arranged by atomic mass, but not in the modern periodic table?
13.
Calcium (Z = 20) and sulphur (Z = 16) combine to form the ionic compound calcium sulphide. Complete the table for the ions in it.
[2]| Ion | Number of protons | Number of electrons | Electron configuration |
|---|---|---|---|
| Ca2+ | |||
| S2− |
14.
Aluminium powder burns in oxygen: 4Al + 3O2 → 2Al2O3. Using the atomic masses Al = 27 u and O = 16 u, find the total mass of the reactants and the total mass of the products. Which law does the result show?
[2]15.
A, B, C and D stand for atoms or ions. Name the type of chemical reaction shown by each pattern.
(i) A + B → AB (ii) AB → A + B (iii) A + BC → AC + B (iv) AB + CD → AD + CB
[2](i) A + B → AB (ii) AB → A + B (iii) A + BC → AC + B (iv) AB + CD → AD + CB
16.
For pickling lemons, Ammini’s mother needs 250 g of a salt solution that is 8 % salt by mass. How much salt and how much water must she take?
[2]17.
Raju wants to show that washing soda (അലക്കുകാരം, Na2CO3·10H2O) is a carbonate. (a) He adds barium chloride solution to a solution of washing soda. What does he see? (b) He then adds dilute hydrochloric acid to what was formed. What does he see, which gas is given off, and how can this gas be identified?
[2]18.
(a) How many hydrogen atoms are there in a molecule of the alkane that has 12 carbon atoms? (b) An alkene has 16 hydrogen atoms in its molecule. How many carbon atoms does it have? Write its molecular formula.
[2]Section CAnswer all questions · 6 × 3 = 18 marks
19.
The atomic numbers of three elements P, Q and R are 5, 12 and 16 (the letters are not the real symbols). Write the electron configuration of each, and find its period number and group number. Give the reasons.
[3]20.
Potassium (Z = 19) burns in oxygen (Z = 8) to form the ionic compound potassium oxide. (a) Write the electron configurations of potassium and oxygen. How many electrons does each potassium atom give away, and how many does an oxygen atom take? (b) Draw the electron dot diagram to show the formation of potassium oxide. (c) Write the electron configurations of the two ions and the formula of the compound.
[3]21.
Balance the following equations.
(a) Al + HCl → AlCl3 + H2
(b) C2H4 + O2 → CO2 + H2O (burning of ethene)
(c) Fe2O3 + H2 → Fe + H2O (hydrogen as a reducing agent)
[3](a) Al + HCl → AlCl3 + H2
(b) C2H4 + O2 → CO2 + H2O (burning of ethene)
(c) Fe2O3 + H2 → Fe + H2O (hydrogen as a reducing agent)
22.
At a juice shop, sugar syrup is made by dissolving 60 g of sugar in 240 g of water. (a) Find the mass percentage of sugar in the syrup. (b) For one glass of kulukki sarbath, 50 g of this syrup is mixed with 150 g of water. How many grams of sugar are there in the glass? (c) Find the mass percentage of sugar in the sarbath. (Ignore the lime juice and basil seeds.)
[3]23.
The figure shows how hydrogen is made in the laboratory. (a) Name A (a metal) and B (an acid). (b) Write the balanced equation for the reaction and name the type of reaction. (c) What is observed when the burning splinter C is brought to the mouth of the test tube? What does it show?
[3]24.
The carbon skeletons of three hydrocarbons P, Q and R are given (hydrogen atoms not shown). (a) Complete each structure by adding hydrogen atoms so that every carbon atom has four bonds. (b) Write the molecular formula of each and say whether it is an alkane, alkene or alkyne. (c) Write the IUPAC name of each.
[3]Section DAnswer all questions · 4 × 4 = 16 marks
25.
Read the situation and answer. On a visit to the old house of her grandmother, Meera found a CRT television – a cathode ray tube. Her teacher showed the class this picture of the discharge tube used by scientists such as William Crookes.
(a) Name the electrodes P and Q. (b) When the tube contains air at normal pressure, no current flows through it even at a very high voltage. Why? What is done with R to make the discharge take place? (c) The glow at the ZnS coating stays the same whatever gas is taken in the tube and whatever metal the electrodes are made of. What did scientists conclude from this? Name the particles. (d) Goldstein used a cathode with holes in it in a similar tube and found rays coming out behind the cathode. Name these rays and give one way in which they differ from the rays from P.
[4](a) Name the electrodes P and Q. (b) When the tube contains air at normal pressure, no current flows through it even at a very high voltage. Why? What is done with R to make the discharge take place? (c) The glow at the ZnS coating stays the same whatever gas is taken in the tube and whatever metal the electrodes are made of. What did scientists conclude from this? Name the particles. (d) Goldstein used a cathode with holes in it in a similar tube and found rays coming out behind the cathode. Name these rays and give one way in which they differ from the rays from P.
26.
Sea shells burnt to make lime (chunnambu) in Kerala contain the element X. The orbit diagram of an atom of X is given.
(a) Write the atomic number, the mass number and the electron configuration of X. (b) Find the period number and the group number of X. Give the reasons. (c) Name the family of X. Name one other element (Z ≤ 20) with similar chemical properties and say why they are similar. (d) Element Y has one proton fewer than X. Write the configuration of Y. Are X and Y in the same period or in the same group?
[4](a) Write the atomic number, the mass number and the electron configuration of X. (b) Find the period number and the group number of X. Give the reasons. (c) Name the family of X. Name one other element (Z ≤ 20) with similar chemical properties and say why they are similar. (d) Element Y has one proton fewer than X. Write the configuration of Y. Are X and Y in the same period or in the same group?
27.
Read the passage and answer. Raghavan, a coconut farmer, sprays Bordeaux mixture on his palms to protect them from മഹാളി (mahali). Bordeaux mixture is made from copper sulphate solution and lime. The lime is made by strongly heating sea shells (calcium carbonate) to get quicklime, and then adding water to the quicklime, which becomes very hot. The agricultural officer warns him not to keep copper sulphate solution in an iron bucket.
(a) CaCO3 → CaO + CO2↑ – name the type of this reaction. (b) CaO + H2O → Ca(OH)2 – name the type of reaction and write one sign that shows a chemical change. (c) Write the equation for the reaction of iron with copper sulphate solution. Name its type and say what Raghavan would see in the bucket. (d) When the two are mixed: CuSO4 + Ca(OH)2 → Cu(OH)2↓ + CaSO4. Name the type of this reaction and give the reason.
[4](a) CaCO3 → CaO + CO2↑ – name the type of this reaction. (b) CaO + H2O → Ca(OH)2 – name the type of reaction and write one sign that shows a chemical change. (c) Write the equation for the reaction of iron with copper sulphate solution. Name its type and say what Raghavan would see in the bucket. (d) When the two are mixed: CuSO4 + Ca(OH)2 → Cu(OH)2↓ + CaSO4. Name the type of this reaction and give the reason.
28.
A school science club in Kochi is comparing fuels for a project on cleaner transport. The bar chart (textbook Fig 7.2) gives the calorific values of some fuels.
(a) What is meant by calorific value? Which fuel in the chart has the highest calorific value? (b) Find the heat released when 5 g of hydrogen burns completely. (c) What mass of carbon monoxide must burn completely to give the same amount of heat? (d) Write one merit and one limitation of hydrogen as a fuel.
[4](a) What is meant by calorific value? Which fuel in the chart has the highest calorific value? (b) Find the heat released when 5 g of hydrogen burns completely. (c) What mass of carbon monoxide must burn completely to give the same amount of heat? (d) Write one merit and one limitation of hydrogen as a fuel.
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