Introductory Pages Flashcards
Usability of materials
Some elements and compounds are naturally found and used in their native state.
Such examples are gold which is used in jewellery and limestone (calcium carbonate) is used in the building industry.
Obtaining substances from other chemicals
Other substances are obtained from other chemicals by using different chemical reactions.
For example, iron(III) oxide, also known as haematite, contains iron which has many uses in various alloys and structures. However, iron needs to be extracted from iron(III) oxide before it can be of any use. Therefore, iron(III) oxide needs to be chemically changed to iron metal.
Physical changes
When a physical change happens, no new substances are formed.
These physical changes are often changes in state such as melting, freezing, boiling, and condensing. A physical change is a change to a sample of matter in which some properties of the material change, but the identity of the material does not. Physical changes that involve a change of state are reversible.
Example of reversible physical change
For example, when liquid water is heated, it changes to water vapour. Even though the physical properties have changed, the molecules are the same as before. This change is reversible. Likewise, melted ice may be refrozen, so melting is a reversible physical change as well.
Molecules of water during changes of state
The diagram shows that the molecules of water do not change when it undergoes changes of state.
Reversible change of dissolving a salt in water
Dissolving a salt in water is a reversible change since the mixture can be easily separated using physical separation techniques.
Just remember that you can do it, future doctor. Sending lots of love .
What happens when a chemical change occurs?
Matter is neither created nor destroyed. Instead, the particles of a substance rearrange themselves to form new chemicals.
What happens to a substance during a chemical change?
A substance with a certain set of properties changes into a different substance with different physical and chemical properties.
What do substances that react together form?
Substances that react together (reactants) form new substances (products).
What are some indicators of a chemical change?
Production of light (flame), effervescence (production of gas bubbles), change in smell, change in colour, temperature change, and products formed may have a different state of matter than the reactants.
What is an example of a chemical change?
An example of a chemical change is burning LPG on a stove, resulting in the formation of new chemicals (carbon dioxide and water vapour).
Example sentence: When LPG is burned, it produces carbon dioxide and water vapour.
What is the law of conservation of mass?
During chemical or physical changes, mass is conserved, meaning that matter is neither created nor destroyed.
What is the total mass relationship between reactants and products in a chemical reaction?
The total mass of the reactants is equal to the total mass of the products.
Why is the total number of elements on both sides of a chemical reaction equal?
In a chemical reaction, the total number of elements on the left-hand side is equal to the total number of elements on the right-hand side. This is due to the law of conservation of mass.
What are the three states of matter?
Solids,liquid and gas
How do the shape of solids,liquids and gases differ?
Solids=have a fixed shape and volume
Liquids=take the shape of the container but have a fixed volume
Gases= of not have a fixed shape of volume and will expand in their container
Describe the volume characteristics of solids,liquids and gases.
Solids: have a fixed volume
Liquids:have a fixed volume but take the shape of the container
Gases: do not have a fixed volume and will expand to fill the available space
Why are gases more compressible than solids and liquids?
Gases are more compressible because there is a lot of space between the particles, allowing them to be pushed closer together. In contrast, particles in solids and liquids are much closer together, making them less compressible.
Explain the arrangement of particles in solids, liquids, and gases.
In solids, particles are tightly packed in a
fixed, orderly arrangement.
• In liquids, particles are close together but can move past each other, allowing the liquid to flow.
In gases, particles are tar apart and move
freely, filling the available space.
How does the kinetic theory of matter relate to the states of matter?
The kinetic theory of matter states that all matter is made up of particles in constant motion. The amount of kinetic energy these particles have determines their state: solids have the least kinetic energy, liquids have more, and gases have the most.
What role do forces of attraction play in the properties of solids, liquids, and gases?
1)In solids, strong forces of attraction hold the particles closely together in a fixed position.
2)In liquids, the forces of attraction are weaker than in solids, allowing particles to move past each other.
3)In gases, the forces of attraction are very weak, allowing particles to move freely and spread out.
What is the significance of kinetic energy in the behavior of particles in different states of matter?
Kinetic energy determines the movement and arrangement of particles in different states of matter. Higher kinetic energy means particles move more freely and are less tightly bound, as seen in gases, while lower kinetic energy means particles are more tightly bound and move less, as seen in solids.
How does temperature affect the volume of gases?
As the temperature increases, the kinetic energy of gas particles increases, causing them to move faster and spread out more, which increases the volume of the gas.
