Question

5. Which is magnetic-iron wire or magnesium foil?
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Answer 1

Answer:

Q1) Which is denser Sodium or Zinc ?

Ans:

Sodium

Q2) Which has a higher melting point a thin tungsten wire or a thick iron nail?

Ans:

A thin tungsten wire.

Q3) What will not react with alkali , a copper sheet or an aluminum sheet.

Ans:

A Copper sheet.

Q4) what is more reactive – Sodium or Lead?

Ans:

Sodium

Q5) Which is magnetic – Iron wire or magnesium foil?

Ans:

Iron wire.

Q6) Which is harder – a piece of Copper or diamond?

Ans:

Diamond.

Q7) Explain malleability with an example.

Ans:

Most metals can be hammered into thin sheets or foils without breaking. This property is known as malleability.

Gold, Silver, Lead and Aluminum are high malleable metals.

Q8) Why are electric wire made from Copper.

Ans:

Electric wire are made from Copper because it is cheap and good conductor of electricity.

Q9) why are cooking utensils made from metals?

Ans:

Cooking utensils are made from metals because they are good conductors of heat.

Q10) Why is Sodium stored in paraffin wax ?

Ans:

Sodium is stored in paraffin wax because Sodium is highly reactive metal.

Q11) why are Helium and Neon are called Nobel gases?

Ans:

Helium and Neon are called Nobel gases because they do not react with other elements.

Q12) What are alloys? Give one example.

Ans:

An alloy is obtained by mixing two or more metals and a non-metal.

Ex: Brass.

Q13) state any four physical properties of metals

Ans:

1- strong

2- hard

3- high melting and boiling points

4- high density

5- malleable

6- ductile

7- good conductor of heat and electricity

8- lustrous

Q14) How rust is formed?

Ans:

Iron reacts with Oxygen in the presence of water or moisture to form iron oxide. Iron oxide is commonly known as rust.

Iron + Oxygen -----Water-----à Iron Oxide

4Fe + 3O2 ---------H2O---------à 2Fe2O3

Q15) Explain the reaction between Sodium and Water

Ans:

Sodium metal reacts vigorously with water giving out a lot of heat to form a colourless solution of sodium hydroxide and Hydrogen gas.

Q16) What is a displacement reaction? Explain with an example.

Ans:

The reactivity series gives the information about displacement reactions in which one element displaces the other because it is more reactive.

Displacement reaction take place when a metallic salt solution react with another metal.

Ex: the Copper sulphate solution reacts with iron. Iron is more reactive than Copper, that is why iron displace Copper from Copper Sulphate and forms Iron Sulphate .

Iron + Copper Sulphate ---------à Copper + Iron Sulphate

Fe + CuSo4 ------------à Cu + FeSo4

Q17) Mention any two ways of preventing iron from rusting

Answer 2

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Iron wire is magnetic.