PAF Chapter Comprehensive Worksheet May 2018 Science Class 7 (Answering Key)

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1 The City School PAF Chapter Comprehensive Worksheet May 2018 Science Class 7 (Answering Key) The City School / PAF Chapter/ Comprehensive Worksheet/ May 2017/ Science / Class 7 / Ans Key Page 1 of 8

2 SECTION A: OBJECTIVE Q.1 Multiple choice question [ /20] 1. Living things are placed into the following eight taxonomic groups. a. Domain, kingdom, phylum, class, order, family, genus and species. b. Kingdom,class, order, domain, family, genus, phylum and species. c. Class, order, kingdom, domain, family, genus, phylum and species. d. Domain, family, genus, phylum, order, phylum, kingdom and species. 2. Modern man belongs to the genus a. Sapiens b. Homo c. Primata d. Hominid 3. Non Vascular plants live in a. Deserts b. Dry places c. Damp places d. Places 4. Sea URchin is an example of a. Echinoderms b. Cnidarians c. Sponges d. Annelids 5. Molecules of elements consists of a a. Fixed number of only one type of atom b. Fixed number of only two type of atom c. Fixed number of only three type of atom d. Fixed number of only four type of atom 6. CH4 is an example of a. Molecule of proton b. Molecule of element c. Molecule of compound d. Molecule of electron 7. In combustion or burning, a substance combines with a. Carbon b. Helium c. Oxygen d. Hydrogen 8. Which gas is produced with oxygen to produce carbon dioxide and water a. Carbon b. Nitrogen c. Neon d. Methane 9. When concentrated sulphuric acid is mixed with sugar in a beaker a. Carbon is formed b. Oxygen is formed c. Argon is formed d. Nitrogen is formed 10. Taj Mahal is affected by acid rain because acid rain consists of a. Dilute sulphuric acid b. Dilute calcium c. Dilute carbon d. Dilute oxygen The City School / PAF Chapter/ Comprehensive Worksheet/ May 2017/ Science/ Class 7 / Ans Key Page 2 of 8

3 11. Solar cells converts light energy from the sun directly into a. Non renewable energy b. Electrical energy c. Chemical energy d. Hydroelectric energy 12. When animal and plant matter rot in the absence of air a. Bio mass is given off b. Biogas is given off c. Fossil fuel is given off d. None of the above 13. From fermentation of sugar cane a type of alcohol a. Methane is produced b. Butane is produce c. Ethanol is produced d. Propane is produced 14. To control Electrical current a. Ammeter are used b. Electric cell are used c. Bells are used d. Resistors are used 15. The SI unit of ampere is a. Am b. A c. na d. Na 16. Electrons are a. Negative b. Positive c. Neutral d. None of above 17. Electrical component which opposes the flow of current. a. Battery b. Switch c. Resistor d. Ammeter 18. During the hydrolysis of water, an electric current is passed through water to break it down into a. Hydrogen and carbon b. Carbon and nitrogen c. Hydrogen and neon d. Hydrogen and oxygen 19. The energy needed for photosynthesis is a. Heat energy b. Water energy c. Light energy d. Calcium energy 20. A chemical reaction in which a substance burns in oxygen to form an oxide is known as a. Decomposition b. Combustion c. Combination d. Conversation The City School / PAF Chapter/ Comprehensive Worksheet/ May 2017/ Science/ Class 7 / Ans Key Page 3 of 8

4 Q.2 Fill in the blanks. [ /10] a. Seedless Vascular plants do not produce flowers and seeds. b. Spring anteater is the example of monotremes (mammals). c. Each sulphur molecule is made up of eight sulphur atoms. d. The number of each type of atom present is denoted by a Subscript. e. The process of breaking down a substance into simpler substance is called thermal decomposition. f. No mass is gain or lost during a chemical reaction, which is called conservation of mass. g. When a dilute acid reacts with carbonates, carbon dioxide gas is produced. h. Carbon dioxide can turn limewater milky. i. A non-luminous bunsen flame has a higher energy output. j. A fuse is made up of a short thin piece of wire. Q.3 State true or false and re-write the false statement. [ /10] a. If a current of 5 A flows through a fuse with a rating of 3A, the fuse will not melt. [False] If a current of 5 A flows through a fuse with a rating of 3A, the fuse will melt. b. Crude oil is an example of Non renewable energy. [True] c. A reason we need to conserve energy is that supplies of solar heater are limited. [False] A reason we need to conserve energy is that supplies of fossil fuels are limited. d. Solar cells have panels which are painted black to trap heat energy from sun. [False] Solar heater have panels which are painted black to trap heat energy from sun. e. Electric current flows from the positive terminal to negative terminal. [True] f. The energy from cells and batteries come from the physical reaction which takes place outside them. [False] The energy from cells and batteries come from the chemical reaction which takes place inside them. g. Rheostats resistance cannot be changed. [False] Rheostats resistance can be changed. h. Fuses are short thin pieces of wire connected in circuits to prevent large currents from flowing through the circuits. [True] i. In parallel circuit, resistance increases as more resistors are added. [False] In parallel circuit, resistance decreases as more resistors are added. j. The process of breaking down a substance into simpler substances by heating is called electrical hydrolysis. [False] The process of breaking down a substance into simpler substances by heating is called thermal decomposition. The City School / PAF Chapter/ Comprehensive Worksheet/ May 2017/ Science/ Class 7 / Ans Key Page 4 of 8

5 Q4. Match Column A with Column B and write in Column C. [ /10] Column A Column B Column C a. Have Vascular Tissues and are able to live in dry places a) Birds 1,b b. Are Warm-blooded and lay eggs with hard shells b) Vascular Plants 2,a c. Dead pollen grains move when bombarded with the water particles d. Matter is made up of small discrete particles that are in constant random motion c) Brownian Motion d) Particle Model of Matter 3,d 4,c e. When a solid is heated particles gain energy and vibrate faster until the attractive forces between the particles fail to hold them together e) Molecules 5,f f. Made up of two or more atoms chemically combined together. f) Melting 6,e g. Is an eclectically charged particle formed when atom loses or gains an electron g) Chemical change 7,h h. Changes in state such as melting, freezing and etc. h) Ions 8,i i. Cooking of food i) Is a switch 9,j j. j) Physical Change 10,i Q5a. State whether the sources are renewable or non-renewable energy resources. [ /06] a) Solar Renewable b) Biomass Renewable c) Nuclear Non- Renewable d) Thermal Non- Renewable e) Crude oil Non- Renewable f) Tides Renewable The City School / PAF Chapter/ Comprehensive Worksheet/ May 2017/ Science/ Class 7 / Ans Key Page 5 of 8

Q5b. Draw the atomic structure of the following atoms and ions.

acid e) Oxygen + Hydrogen f) Calcium carbonate + dilute sulphuric acid a. Magnesium oxide b.

6 Q5b. Draw the atomic structure of the following atoms and ions. [ /04] a) 6 C b) 12 Mg c) 17 Cl -1 d) 19 K a. b. c. d. SUBJECTIVE Q6a. Complete the following equations. [ /6] a) Magnesium + Oxygen b) Sulphur + Oxygen c) Methane + Oxygen d) Zinc + dilute sulphuric acid e) Oxygen + Hydrogen f) Calcium carbonate + dilute sulphuric acid a. Magnesium oxide b. Sulphur dioxide c. Carbon dioxide + water d. Zinc sulphate + Hydrogen e. Water f. Carbon dioxide + calcium sulphate + water The City School / PAF Chapter/ Comprehensive Worksheet/ May 2017/ Science/ Class 7 / Ans Key Page 6 of 8

7 Q6b. What do you understand by electrolysis? Explain it with examples. [ /02] The chemical decomposition of an electrolyte by passing an electric current. Example water Q6c. Describe ruther fords atomic model. [ /02] The atom has a nucleus surrounded by electrons. Q7a. State the function of the following. [ /04] Switch Battery Fuse Ammeter Used to open and close the circuit Provides energy to the circuit Made up of short thin piece of wire and allows certain amoun current to pass through, if more current flows than its rating wire melts and break the circuit. A device used to measure the current. Q7b. Name and explain the model which is accepted by scientists now a days. [ /03] Quantum model of an atom. Negatively charged electrons move around the positively charged nucleus. Randomly and are most likely to be found in regions called orbit. Q7c. Why wood is not called a fossil fuel? [ /03] Wood is not considered as a fossil fuel because it is a renewable energy resource whereas fossil fuels are renewable energy resource and the formation of fossil fuels require millions of years. Q8a. Complete the table. [ /12] H 2 O CCl 4 NH 3 CaCO 3 Chemical formula Type of atoms Number of atoms Is it a molecule of an element or of a compound? Hydrogen and oxygen 3 Molecule of compound 1 carbon atom 4 chlorine atoms 5 Molecule of compound 1 nitrogen atom 3 hydrogen atoms 4 Molecule of compound 1 calcium atom 1 carbon atom 5 Molecule of compound 3 oxygen atoms Q8b. Write three ways to conserve energy. [ /03] The three ways to conserve energy are, 1. Switch off the lights when they are not in use. 2. Go to bed at dusk instead of late at night to save electricity. 3. Use energy saving light bulbs instead of incandescent light bulb. The City School / PAF Chapter/ Comprehensive Worksheet/ May 2017/ Science/ Class 7 / Ans Key Page 7 of 8

8 Q9a. Write the importance of classification. [ /04] Text book Pg. 32 Q9b. Write the difference between angiosperms and gymnosperms. [ /04] Text book Pg 38 Q9c. How are mammals different from birds? [ /02] Text book Pg 40 and 41 The City School / PAF Chapter/ Comprehensive Worksheet/ May 2017/ Science/ Class 7 / Ans Key Page 8 of 8

The City School. PAF Chapter Comprehensive Worksheet May 2018 Science Class 7. Candidate Name: Index Number: Section: Branch/Campus: Date:

The City School. PAF Chapter Comprehensive Worksheet May 2018 Science Class 7. Candidate Name: Index Number: Section: Branch/Campus: Date: The City School PAF Chapter Comprehensive Worksheet May 2018 Science Class 7 Candidate Name: Index Number: Section: Branch/Campus: Date: Maximum Marks: 50 Time Allowed: 1 hour 30 minutes INSTRUCTIONS: