Last updated on February 6th, 2024 at 12:47 am
Metals are generally good conductors of heat and electricity.
Metals are malleable and ductile, meaning they can be hammered into thin sheets and drawn into wires.
Most metals react with oxygen to form metal oxides, which are basic in nature.
Metals generally react with acids to form salts and hydrogen gas.
Non-metals are poor conductors of heat and electricity.
Non-metals are brittle and cannot be easily hammered into thin sheets or drawn into wires.
Non-metals react with oxygen to form non-metal oxides, which are acidic or neutral in nature.
Non-metals may react with acids, but the products are not always salts and hydrogen gas.
Why is gold and silver used for making ornaments?
Gold and silver are used for making ornaments because they are noble metals, which means they are resistant to corrosion and do not react easily with environmental factors like air and moisture. Additionally, they have a high luster, are malleable, and can be easily shaped into intricate designs.
What do you understand by reactivity series?
The reactivity series is a list of metals arranged in order of their decreasing chemical activity. The series helps predict the likelihood of a metal reacting with other substances. Metals higher in the reactivity series tend to lose electrons more readily and are more likely to react with acids or other compounds.
How much carat is pure gold? Why is pure gold not used for making ornaments?
Pure gold is 24 carats. Pure gold is not used for making ornaments because it is too soft and malleable. The addition of other metals, such as copper or silver, in varying proportions forms alloys like 18-carat gold, which are more durable and suitable for jewelry.
What are alloys? Give names of any four alloys and write their constituents and uses.
Alloys are mixtures of two or more elements, with at least one being a metal. Four examples are:
- Brass: Copper (Cu) and Zinc (Zn), used in making musical instruments.
- Bronze: Copper (Cu) and Tin (Sn), used in making sculptures and medals.
- Stainless Steel: Iron (Fe), Chromium (Cr), Nickel (Ni), used in kitchenware and construction.
- Duralumin: Aluminum (Al), Copper (Cu), used in aircraft construction.
What is metal corrosion? What are the ways to protect corrosion?
Metal corrosion is the gradual deterioration of metal due to its reaction with environmental factors, such as oxygen and moisture. Ways to protect against corrosion include:
- Applying a protective coating (painting).
- Applying grease or oil to create a barrier.
- Using metallic coatings (galvanization).
- Making alloys that resist corrosion.
Why is graphite used as an electrode?
Graphite is used as an electrode because it is a good conductor of electricity and has high thermal stability. It can withstand the high temperatures and intense conditions in various electrical applications, such as batteries and electrolysis cells.
