Mark ‘T’ if the statement is true and ‘F’ if it is false.
(a) Generally non-metals react with acids. ( )
(b) Sodium is a very reactive metal. ( )
(c) Copper displaces zinc from zinc sulphate solution. ( )
(d) Coal can be drawn into wires. ( )
(a) False
This statement is false because non- metals generally do not react with metal whereas metal does.
(b) True
This statement is true because, sodium is a very reactive metal. It is stored in kerosene, it catches fire easily.
(c) False
This statement is false because copper is less reactive than zinc. So, it cannot displace it.
(d) False
This statement is false because coal cannot be drawn into wires. Coal is a form of carbon which is a non- metal. Non- metal does not show the property of ductility.
Can you store lemon pickle in an aluminium utensil? Explain.
Which of the following can be beaten into thin sheets?
(a) Zinc (b) Phosphorus (c) Sulphur (d) Oxygen
Fill in the blanks :
(a) Phosphorus is very _________ non-metal.
(b) Metals are ________ conductors of heat and ________ .
(c) Iron is __________ reactive than copper.
(d) Metals react with acids to produce _________ gas.
In the following Table some substances are given in Column I. In Column II some uses are given. Match the items in column I with those in Column II.
Column I | Column II |
---|---|
(i) Gold (ii) Iron (iii) Aluminium (iv) Carbon (v) Copper (vi) Mercury |
(a) Thermometers (b) Electric Wire (c) Wrapping food (d) Jewellery (e) Machinary (d) Fuel |
Give reasons for the following:
(a) Aluminium foils are used to wrap food items.
(b) Immersion rods heating liquids are made up of metallic substances.
(c) Copper cannot displace zinc from its salt solution.
(d) Sodium and potassium are stored in kerosene.
Saloni took a piece of burning charcoal and collected the gas evolved in a test tube.
(a) How will she find the nature of the gas ?
(b) Write down word equations of all the reactions taking place in this process.
What happens when
(a) Dilute sulphuric acid is poured on a copper plate?
(b) Iron nails are placed in copper sulphate solution?
Write word equations of the reactions involved.
One day Reeta went to a jeweller’s shop with her mother. Her mother gave old gold jewellery to the goldsmith to polish. Next day when they brought the jewellery back, they found that there was a slight loss in its weight. Can you suggest a reason for the loss in weight?
Which of the following statements is correct?
(a) All metals are ductile.
(b) All non-metals are ductile.
(c) Generally, metals are ductile.
(d) Some non-metals are ductile.
Some properties are listed in the following Table. Distinguish between metals and non-metals on the basis of these properties.
Properties | Metals | Non-Metals |
---|---|---|
1. Appearance |
Fill in the blanks
(a) Most liquids that conduct electricity are solutions of , ______________ and ______________.
(b) The passage of an electric current through a solution causes ______________ effects.
(c) If you pass current through copper sulphate solution, copper gets deposited on the plate connected to the terminal of the battery.
(d) The process of depositing a layer ofany desired metal on another material by means of electricity is called .
Give two examples each of situations in which you push or pull to change the state of motion of objects.
Fill in the blanks:
(a) Friction opposes the _____________ between the surfaces in contact with each other.
(b) Friction depends on the _____________ of surfaces. (c) Friction produces __________.
(d) Sprinkling of powder on the carrom board ________ friction.
(e) Sliding friction is ___________ than the static friction.
List conditions under which combustion can take place.
Indicate whether the following statements are True (T) or False (F).
(a) Unicellular organisms have one-celled body. (T/F)
(b) Muscle cells are branched. (T/F)
(c) The basic living unit of an organism is an organ. (T/F)
(d) Amoeba has irregular shape. (T/F)
Which of the following cannot be charged easily by friction?
(a) A plastic scale
(b) A copper rod
(c) An inflated balloon
(d) A woollen cloth.
Fill in the blanks:
(a) A place where animals are protected in their natural habitat is called .
(b) Species found only in a particular area is known as .
(c) Migratory birds fly to far away places because of changes.
Suppose you are in a dark room. Can you see objects in the room? Can you see objects outside the room. Explain.
What are the different ways in which water gets contaminated ?
Explain the importance of reproduction in organisms.
How many images of a candle will be formed if it is placed between two parallel plane mirrors separated by 40 cm?
Arrange the following boxes in proper order to make a flow chart of sugarcane crop production.
Explain the process of formation of petroleum.
When a glass rod is rubbed with a piece of silk cloth the rod
(a) and the cloth both acquire positive charge.
(b) becomes positively charged while the cloth has a negative charge.
(c) and the cloth both acquire negative charge.
(d) becomes negatively charged while the cloth has a positive charge.
Explain circumstances leading to acid rain. How does acid rain affect us?
The process that you saw in Activity 14.7 is used for purification of copper. A thin plate of pure copper and a thick rod of impure copper are used as electrodes. Copper from impure rod is sought to be transfered to the thin copper plate. Which electrode should be attached to the positive terminal of battery and why?
Make a labelled diagram of a candle flame.
Explain why the sliding friction is less than the static friction.
Gurmit wanted to perform Activity 16.8 using a laser torch. Her teacher advised her not to do so. Can you explain the basis of the teachers advise?
An inflated balloon was pressed against a wall after it has been rubbed with a piece of synthetic cloth. It was found that the balloon sticks to the wall. What force might be responsible for the attraction between the balloon and the wall?