Lakhmir singh solutions science class 8 Solutions for Chapter 4 materials metals and non metals

Exercises in Chapter 4 materials metals and non metals Grade 8

Exercise

Questions in Exercise

What is the general name of the elements whose properties are intermediate between those of metals and nonmetals?

Name one metal and one nonmetal which exists in the liquid state at room temperature.

Name two metals which are soft and can be easily cut with a knife.

Name the property ;

(a) Which allows metals to be hammered into thin sheets.

(b) Which enables metals to be drawn into wires.

If a metal coin is dropped on a hard floor, it produces a ringing sound. What is this property of metals known as?

Name the property of iron metal due to which it can be hammered to make objects of different shapes such as an ax, a spade, or a shovel.

Write a word equation for the reaction of magnesium with oxygen

(a) Name one metal which reacts with dilute hydrochloric acid to produce hydrogen gas.

(b) Name one metal which does not react with dilute hydrochloric acid.

An element forms an oxide which is basic in nature. State whether the element is a metal or a non-metal?

Name the gas evolved when a metal reacts with dilute acid.

Which metal is more reactive: iron or zinc?

Name the gas evolved when a metal reacts with water.

How do metal oxides differ from non-metal oxides?

An element forms an oxide which is acidic in nature. State whether the element is a metal or a non-metal?

What is the general name of the elements whose properties are intermediate between those of metals and nonmetals?

State one chemical property which can be used to distinguish metal from a non-metal.

Name a non-metal which is a good conductor of electricity?

Name a non-metal which is very hard.

Iron metal reacts slowly with the oxygen and moisture of damp air to form rust. State, whether the rust formed, is acidic, basic, or neutral.

Name any five objects used in our everyday life which are made of metals.

Name two metals that are used for making electric wires.

Name two metals that are used for making cooking utensils and water boilers for factories.

Where is the iron present in our body?

Which metal is used to galvanize iron to protect it from rusting?

Name the metal which is used in making thermometers.

Name the metal which is used to make thin foils for packaging medicines, chocolates, and food items, etc.

Name two metals that are used to make jewelry.

Name the gas produced when aluminum foil reacts with:

(a) dilute hydrochloric acid. (b) Sodium Hydroxide solution.

Name the non-metal used to make a purple-colored solution which is applied on cuts and wounds as an antiseptic.

Compare the properties of metals and nonmetals with respect to :

(i) malleability

(ii) ductility

(iii) conduction of heat and electricity

What is meant by saying that metals are:

(i) Malleable (ii) Ductile (iii) Lustrous and (iv) Sonorous

Fill in the following blanks with suitable words (a) Metals are _________conductors of heat and__________. (b) Most non-metals are_________ conductors of heat and electricity. (c) Phosphorous is a very_ Non-metal. (d) Metals react with acids to produce_gas. (e) Iron is more_than copper. (f) Metals form_oxides whereas non-metals form_oxide. (g) Sulphur forms………oxide whereas magnesium forms_oxide. (h) A non-metal is used to make an antiseptic solution called tincture_

Define (a) malleability, and (b) ductility.

Give a reason why. (a) Copper metals used for making electric wires. (b) Graphite is used for making electrodes in a cell. (c) Immersion rods for heating liquids are made of metallic substances.

State whether the following statements are true or false? (a) All metals exist in solid form at room temperature. (b) Coal can be drawn into wires. (c) Non-metals react with dilute acids to produce hydrogen gas. (d) Sodium is a very reactive metal. (e) Copper displaces zinc from a zinc sulfate solution. (f) Rust formed on iron objects is basic in nature. (g) Non-metals react with water to form a gas that burns with a ‘pop’ sound.

State two physical properties on the basis of which metals can be distinguished from non-metals.

Which non-metals is used as a fuel?

Name the non-metal which is essential for maintaining life and inhaled during breathing.

Name two non-metals which are used in fireworks (crackers, etc.)

Which non-metal is used in the water purification process to make drinking water supply germ-free?

Name one non-metal used for making fertilizers.

Consider the following materials: Copper, Sulphur, Phosphorus, Carbon (such as pencil lead), Gold, Silver: Which of these materials are: Malleable and ductile; and brittle.

What type of oxides are formed: (a) when metals combine with oxygen? (b) when non-metals combine with oxygen?

The screwdriver used by an electrician has a plastic or wooden handle. Why?

There are two boxes, one made of metal and the other made of wood, which is similar in appearance. How will you find out which box is made of metal?

Consider the following elements: Sodium, Sulphur, Carbon, Magnesium Which of these elements will form: (a) acidic oxides. (b) Basic oxides.

Can you hold a hot metallic pan that is without plastic or a wooden handle? Give the reason for your answer.

Element A is soft, brittle, and does not conduct electricity. Element B is hard, malleable, and 'ductile; and also conducts electricity. Which of the two elements, A or B, is a non-metal?

What is nature (acidic/basic) of the following oxides? (a) Magnesium oxide (b) Sulphur dioxide Given the reason for your choice.

Which metal is less reactive: copper or iron?

State any two physical properties for believing that aluminum is a metal.