Science - Ch6: Elements

Where is DNA found in the body?

In the nuclei of cells

What is the primary function of DNA?

To contain all the genetic information that makes you who you are

What is a polymer?

A compound made of very long chains of smaller molecules

What was the first synthetic polymer created?

Bakelite

What are some common uses of polymers?

Manufacturing plastics, glues, synthetic fibers, and non-stick surfaces

What is silica made of?

Silicon dioxide (SiO2)

What is one major application of optical fibers?

Guiding light signals for high-speed data transmission

What is the common name for potassium nitrate?

Saltpetre

What explosive is created by mixing saltpetre, carbon, and sulfur?

Gunpowder

What role did salt play in ancient civilizations?

It was used for food preservation and as a form of payment

What is a significant environmental issue associated with plastics?

Most plastics are not biodegradable and can remain in landfills for centuries

What are some solutions being researched for plastic waste?

Creating recyclable and biodegradable plastics

What is the relationship between DNA and genetic traits?

The order of molecules in DNA determines traits such as height, skin color, and disease susceptibility.

What was the original form of salt obtained from mines?

Rock salt

Why were cities founded near rock salt mines?

Because it was a valuable resource for preservation and trade.

What are the environmental concerns associated with uranium mining?

It is damaging to the environment and produces dangerous nuclear waste.

What devastating event demonstrated the power of uranium?

The detonation of the first uranium-fueled atomic bomb over Hiroshima in 1945.

What is the difference between pure iron and steel?

Steel is an alloy of iron mixed with carbon, making it harder and less likely to rust.

What major advancements did steel contribute to?

Improved tools, weapons, and construction materials.

What was the first metallic element to be extracted from rock?

Copper.

What alloy is formed by mixing copper with tin?

Bronze.

What are aqueous solutions?

Solutions where water is the solvent.

What is a colloid?

A mixture where solid particles are so small that they never settle to the bottom of the liquid.

What is the significance of copper?

It is an excellent conductor of electricity and is widely used in electrical wiring.

What distinguishes a suspension from other mixtures?

Solid particles are larger and heavier, causing them to eventually settle at the bottom.

What does it mean for liquids to be miscible?

They can dissolve in one another, such as detergent in water.

What is a foam?

A mixture of gas bubbles in a liquid.

What is a mist or fog?

A mixture of tiny water droplets suspended in a gas.

What is smoke composed of?

Solid particles suspended in a gas.

What are alloys?

Mixtures of metals with other metals or non-metals.

What is the chemical formula for table salt?

NaCl, containing 1 sodium and 1 chlorine atom.

What is a molecular formula?

It describes the composition of a molecule.

What is the molecular formula for water?

H2O, containing 2 hydrogen atoms and 1 oxygen atom.

What are the properties of compounds compared to their constituent elements?

The properties of compounds are usually very different from the properties of the elements that make them up.

What is a crystal lattice?

A structured arrangement of atoms bonded strongly together, forming hard solids at room temperature.

What is the molecular formula for carbon dioxide?

CO2, containing one carbon atom and two oxygen atoms.

What is graphite?

A form of carbon that forms sheets of atoms stacked together, allowing it to slide easily.

What is the significance of silicon in relation to glass?

The main ingredient in glass and is used in optical fibers for information transmission.

What is the difference between elements, compounds, and mixtures?

Elements consist of one type of atom, compounds are made of molecules containing different types of atoms, and mixtures contain a variety of molecules and do not have a fixed composition.

What allows metals to be bent, drawn into wires, or hammered into sheets?

The ability of atoms in metallic lattices to slide and move over each other without breaking the lattice.

What are crystal lattices?

Large grid-like structures that repeat the same arrangement of atoms, formed by metallic elements.

What is the molecular formula for oxygen gas?

O₂, containing two oxygen atoms.

What are the properties of non-metallic elements?

They tend to be dull, do not conduct heat or electricity, and are brittle.

What is the primary use of neon (Ne)?

Creating signs of different colors in neon lights.

What characterizes metallic elements?

They are shiny, solid at room temperature (except mercury), good conductors of heat and electricity, malleable, and ductile.

What is the significance of chemical symbols?

They provide a universal way to represent elements, often derived from the element's name in other languages.

What happens to metals when they are bent?

They tend to not break due to the weak joining of atoms in metallic lattices.

What is the molecular formula for nitrogen gas?

N₂, indicating each nitrogen molecule contains two nitrogen atoms.

What is the molecular formula for hydrogen gas?

H₂, indicating each hydrogen molecule contains two hydrogen atoms.

What is the molecular formula for chlorine gas?

Cl₂, indicating each chlorine molecule contains two chlorine atoms.

What is the main characteristic of non-metallic solids?

They tend to break or crumble when bent.

What is the role of argon (Ar) in old-fashioned light globes?

It is used to stop the filament from burning.

What defines the physical properties of an element?

The arrangement of atoms in the element.

What is a common property of metals regarding electricity?

They are good conductors, allowing electricity to flow easily through them.

What does it mean for metals to be malleable?

They can be bent and hammered into sheets.

What does it mean for metals to be ductile?

They can be stretched into wires.