GIỚI THIỆU VỀ HỢP KIM

Multiple Choice

Compare the carbon content in steel and cast iron. Which one has a higher carbon content?

• Steel

• Cast iron

• Both have equal carbon content

• Neither contains carbon

Open Ended

How does the composition of materials affect their resistance to rust and corrosion?

Multiple Choice

Why do you think stainless steel (inox) is more resistant to rust compared to regular iron (sắt)?

• Because inox is a type of iron with added elements that prevent rusting

• Because inox is painted

• Because inox is heavier than iron

• Because inox is used indoors only

Open Ended

What is an alloy and why are alloys commonly used instead of pure metals?

Open Ended

Why do people often use alloys instead of pure metals to make objects in daily life?

Open Ended

Give two examples of objects made from alloys and explain why alloys are chosen for these objects.

Multiple Select

Select all the correct statements about alloys:

• Alloys contain at least one basic metal and other elements.

• Alloys are always magnetic.

• Alloys can have higher hardness and durability than pure metals.

• Alloys are used because they have better properties than pure metals.

Multiple Choice

Which of the following is NOT a reason why alloys are widely used?

• Alloys are usually harder and more durable than pure metals.

• Alloys have better corrosion resistance than pure metals.

• Alloys are always cheaper than pure metals.

• Alloys can combine properties of different elements.

Fill in the Blanks

Pure metals have unique properties that are easily changed in nature. Creating alloys provides new properties that compensate for the limitations of pure metals. Fill in the blank: Creating

helps to overcome the weaknesses of pure metals.

Open Ended

Why are alloys harder than the original metals?

Open Ended

Explain, using atomic structure, why alloys are generally harder than pure metals.

Open Ended

Observe your home and list objects made from alloys. Name the alloy used for each object.

Fill in the Blanks

Ordinary steel contains mainly iron and less than

% carbon.

Multiple Select

Select all correct statements about stainless steel (inox):

• It is mainly made of iron and small amounts of Cr and Ni

• It is easily corroded

• It is used for making kitchen sinks and surgical tools

• It is light and used for making aircraft parts

Multiple Choice

Which of the following is NOT a common use of cast iron (gang)?

• Making kitchen stoves

• Manufacturing gears

• Making surgical tools

• Parts of steam engines

Multiple Choice

Which of the following alloys is commonly used in important applications in daily life and production?

• Cast iron

• Steel

• Aluminum alloy

• All of the above

Open Ended

Explain the importance of cast iron and steel production in modern industry and daily life.

Multiple Select

Which of the following are the main raw materials used in the blast furnace process to produce cast iron?

• Iron ore

• Coke

• Hot air and additives

• All of the above

Open Ended

Describe the main chemical reactions involved in the production of cast iron in a blast furnace.

Fill in the Blanks

The chemical reaction C + O2 →

occurs during the combustion of coke in the blast furnace.

Multiple Select

Which of the following oxides are produced during the steelmaking process when oxygen is blown into molten iron?

• CO2

• SO2

• SiO2

• MnO2

Multiple Choice

What is the main difference in carbon content between cast iron and steel?

• Cast iron has 2-5% carbon, steel has less than 2% carbon

• Steel has 2-5% carbon, cast iron has less than 2% carbon

• Both have the same carbon content

• Cast iron contains no carbon

Open Ended

Why is oxygen gas continuously blown through molten cast iron during the steelmaking process?

Fill in the Blanks

During the steelmaking process, impurities in the raw materials are removed by forming

with CaO, which are then separated from the final product.

Open Ended

Explain how the removal of non-metallic impurities during steel production improves the quality of the final steel product.

Multiple Choice

Which of the following is NOT a stage in the production of cast iron?

• Formation of carbon monoxide

• Formation of cast iron

• Formation of slag

• Electrolysis of iron ore

Fill in the Blanks

Iron doors are more likely to rust than stainless steel doors because stainless steel is a

of iron.

Open Ended

Reflecting on today's lesson about iron and stainless steel, what is one thing you learned that surprised you or that you would like to know more about?