Classification Of Matter

Question 1

Why designing materials matter

Answer 1

The design of materials is a meticulous process that involves carefully tailoring their properties to achieve desired outcomes. By manipulating factors such as composition, structure, and processing conditions, scientists and engineers can create materials with remarkable properties that can withstand extreme temperatures, resist corrosion, conduct electricity, or exhibit unique optical characteristics

Question 2

Give examples of how designing materials can help with global warming issues

Answer 2

The development of solar cells and batteries has accelerated the transition to renewable energy sources, offering a cleaner and more sustainable alternative to fossil fuels.

Question 3

Give an example of how designing matter has helped the human body in terms of medicinal improvement

Answer 3

Advances in materials science have led to the creation of biomaterials that are compatible with the human body, enabling breakthroughs in medical treatments and devices such as artificial joints, pacemakers, and tissue engineering.

Question 4

Properties of materials

Answer 4

Acoustic properties, such as the speed of sound and sound reflection

Atomic properties, such as atomic mass, atomic number, and atomic weight

Chemical properties, such as pH, reactivity, surface tension, and surface energy

Question 5

What is a conductor

Answer 5

materials that allow electricity to flow through them easily. This property of conductors that allow them to conduct electricity is known as conductivity. The flow of electrons in a conductor is known as the electric current.

Question 6

Example of conducters of heat(energy) that conduct electric current

Answer 6

Stainless steel
Iron
Copper
Lead
Graphite

Question 7

Magnetic material

Answer 7

Stainless steel and iron
Amagnetis a material or object that produces a magnetic field.

Question 8

Substances are either

Answer 8

Pure substances or mixtures

Question 9

Draw the flow diagram to show the classification of matter

Answer 9

Included
Pure substances
Elements and compounds
Element: metals, metal lipids and non metals
Compounds: organic and inorganic

Mixtures
Heterogeneous mixtures and homogeneous mixtures

Question 10

Pure substances

Answer 10

Are made of one type of substance eg sugar, each crystal of sugar is made up of the same type of particles(sugar molecules).

A pure substance is a single substance eg a single element or a single compound. A pure substance has no other substances mixed with it.
They are mainly classified into 2 main groups : elements and compounds

Question 11

Elements

Answer 11

Simplest type of pure substance which cannot be broken down by chemical reactions into any simpler types of substances

There are 90 naturally occurring elements on earth and about a dozen more have been artificially produced by nuclear reactions. The artificial elements are unstable and short lived so they are not found in nature. The names and symbols of all the elements appear on the periodic table(pt) and chemical formulae.

Question 12

Compound

Answer 12

Is a pure substance made of two or more elements bonded in a fixed ratio by a chemical reaction.
The chemical composition of compounds is fixed;Substances are bonded in a fixed ratio

Question 13

3 examples of compound, chemical formula, description and diagram of molecule

Answer 13

Water=H2O= 2 hydrogen atoms and 1 oxygen atom
Carbon dioxide= CO2= 1 carbon atom and 2 oxygen atoms
Ammonia(fertilizer for plants)=NH3=1 Nitrogen atom and 3 hydrogen atoms

Question 14

Mixtures

Answer 14

Impure substances which consists of two or more different substances physically blended together in any proportions eg sand and stonused in building may contain two parts of stone for every one part of sand or it may contain 3 parts of sand for every two parts of stone. The stone can be separated from the mixture by sieving it.

Question 15

Sieving

Answer 15

Sieving is a separation technique based on the difference in particle size. The sieve is responsible for retaining the larger particles

Question 16

Substances in a mixture

Answer 16

Are mixed physically and are not chemically bonded to one another
Keep their individual physical properties eg color, solubility, magnetic or non magnetic properties, boiling abd freezing points
Can be separated by physical means eg distillation, evaporation and hand sorting

Question 17

Mixtures are homogeneous when

Answer 17

They are uniform eg all the constituents are in the same phase so that none of them can be clearly identified from the other. Sugar in water, apple juice in water, homogenised milk, vinegar mixed with water are all examples for homogeneous mixtures. Jelly powder dissolved in hot water also forms a homogeneous mixture. the air is a mixture of oxygen and nitrogen gases. Air is also a homogeneous mixture but when the air contains dust particles, it is described as a Heterogeneous mixture

Question 18

Heterogenous mixtures

Answer 18

Are non uniform. They consist of substances of different phases mixed together and or of substances which can be clearly identified in the mixture eg different types of substances in an assortment of sweets or biscuits. A fizzy drink has carbon dioxide gas dissolved in water therefore since there is more than one phase present in the mixture, fizzy drinks are Heterogeneous mixtures. Water droplets suspended in the gases of the atmosphere where fog and mist occur, making fog and mist both Heterogeneous mixtures. Raw cow milk is a Heterogeneous mixture of cream and milk. Oil mixed with water is also a Heterogeneous mixture as oil droplets do not dissolve in water and oil rises to the surface although oil and water are liquids, as in the same phase, they are immiscible

Question 19

Immiscible

Answer 19

Immiscibility is the property where two substances are not capable of combining to form ahomogeneousmixture. The components are said to be “immiscible.” In contrast,fluidsthat do mix together are called “miscible

Question 20

Atom

Answer 20

Smallest building block of Matter that cannot be broken down by chemical means

Question 21

Gases have mass and volume

Answer 21

Here, solids and liquids have definite shape and mass and similarly even gases have only definite mass because mass of a substance is not dependent on their shape. – Therefore, gases take the shape of the container and occupy the complete volume of that particular container.

Question 22

A chemical reaction can’t break down or split an atom

Answer 22

Atoms cannot be subdivided, created, or destroyed. Atoms of different elements can combine in simple whole number ratios to form chemical compounds. In chemical reactions, atoms are combined, separated, or rearranged.

Question 23

Nuclear reaction can break an atom

Answer 23

Nuclear fission is a reaction where the nucleus of an atom splits into two or more smaller nuclei, while releasing energy. For instance, when hit by a neutron, the nucleus of an atom of uranium-235 splits into two smaller nuclei, for example a barium nucleus and a krypton nucleus and two or three neutrons.

Question 24

Nuclear fusion

Answer 24

Nuclear fusion is the process of forcing together two light atomic nuclei and creating a heavier one, in the process taking a tiny amount of matter and turning it into massive amounts of energy.

Question 25

Combined atoms

Answer 25

When atoms combine, they form a molecule123. A molecule is the simplest unit of a covalent compound1. When atoms of two or more elements bond together, they make a compound3. When different types of atoms combine, the result is called a compound2. When atoms combine by forming covalent bonds, the resulting collection of atoms is called a molecule

Question 26

Diatomic molecule

Answer 26

Diatomic molecules are molecules composed of only two atoms, of the same or different chemical elements. If a diatomic molecule consists of two atoms of the same element, such as hydrogen or oxygen, then it is said to be homonuclear. Otherwise, if a diatomic molecule consists of two different atoms, such as carbon monoxide or nitric oxide, the molecule is said to be heteronuclear.

Question 27

Diatomic elements

Answer 27

Group 7: f2, Cl2, Br2, I2, At2, N2, O2, H2Examples of molecules of elements include2:

Water (H2O) - Triatomic

Bleach (sodium hypochlorite) (NaOCl) - Polyatomic

Oxygen (O2) - Diatomic

Hydrogen (H2) - Diatomic

Question 28

Atoms 2

Answer 28

Atoms of an element - single individual atoms

Molecules of an element
Diatomic except for sulfur (2 atoms bonded of the same kind)

Question 29

Levels of representation

Answer 29

Macro(big things we can see)
Symbolic equations to represent what’s happening
Microscopic (molecular)

Question 30

If you bend something and it doesn’t break

Answer 30

Malleable

Question 31

If you bend something and breaks

Answer 31

Brittle

Question 32

Conductor vs insulator

Answer 32

Conductors123are materials that allow electrons to flow freely through them, making them useful for carrying electric current.Insulators123are materials that resist the flow of electrons, so they do not allow electric current to pass through them.If charge is transferred to an insulator at a given location, the excess charge will remain at the initial location of charging

Question 33

Diagram of homogeneous and heterogenous

Question 34

Physical change

Answer 34

The phase changes
Diffusion
Definition: a change which involves energy changes of a substance but where no NEW substances are formed

A liquid defines the shape of an object and to change to a gas energy needs to be added which makes the particles start to move around more which makes the strong force weaker as their phase changes therefore fast particles have more energy.
Forces between molecules decreases

The particles change in speed and energy which affects the forces that holds them which are outside the molecule called the inter molecular forces.
The chemical composition is H20 doesn’t change

Question 35

Chemical change

Answer 35

Oxidation - slow reaction of a metal with oxygen and combustion. (Conductors123are materials that allow electrons to flow freely through them, making them useful for carrying electric current.Insulators123are materials that resist the flow of electrons, so they do not allow electric current to pass through them.If charge is transferred to an insulator at a given location, the excess charge will remain at the initial location of charging)

Question 36

A microscopic view of substances

Answer 36

The smallest particle in an element in an atom
Atoms bond with each other to form different substances

Question 37

How we check the purity of a pure substance

Answer 37

The melting point of a pure substance at which the solid changes to its liquid;the substance melts. Pure substances each have a characteristic melting point, which coincides with its freezing point (the temperature at which the liquid solidifies). The temperature of a pure substance remains constant while it changes phase until all of the substance has changed phase eg from its solid to its liquid

Question 38

How do we check the purity of substances

Answer 38

Impure substances(mixtures) melt at a range of temperaturea eg paraffin wax is made or a mixture of organic compounds called alkanes. The wax melts through a range of temperature from 34°C to 60°C. The melting point of paraffin wax is recorded as the tem9at which the first few droplets appear. The melting point of wax differs from its freezing point which is the temperature at which the last piece of solid is observed, or the temperature at which the first piece of solid is seen when the liquid is cooling.

Question 39

Investigation of the purity of substances

Answer 39

A pure substance melts and freezes at the same fixed temperature. Impure substances do not have a fixed temperature at which they melt or freeze. The temperature of a mixture will continue changing as the substance melts and as it freezes. To check the purity of a substance we therefore observe and take the temperature of the substance at frequent intervals while it melts, and while it freezes.

Question 40

Boiling points of pure substances and mixtures

Answer 40

The boiling point is the temperature at which a pure substance boils and the condensation point is the temperature at which vapor(gas) condenses to become liquid again. The boiling point of a pure substance is the same temperature as it’s condensation point.

Solutions consisting of more than one substance have more than one boiling point eg a mixture of water and alcohol boils at 78 ° C then at 100 °C(at a pressure or 101,3kPa).This is because the individual constituents of a mixture(a solution) retain their physical and chemical properties

Question 41

Crude oil

Answer 41

We separate crude oil into its many constituents by fractional distillation at oil refineries. Each substance in the crude oil boils off at a different temperature. The least dense(lightest) substances boil off at lower temperatures;the more dense substances such as fuel oil boil at higher temperatures. The fractionating column collects the pure distillate for further processing into petroleum products

Question 42

Chromatography

Answer 42

Method used to separate and identify colored constituents of a substances ege, dye, paint or ink.
It separates colors by allowing a solution of the due to be absorbed and move through chromatographic paper. Different colors move through the paper at differing rates. Red travels faster in a given time than blue so the red color will move through a greater distance than the blue.

We use it to find out how many colors are present in a dye, and to check for matching dyes eg the ink used in pens made by a particular manufacturer will have the same composition. When the chromatograph matches that from a particular brand of pen, it is very likely that the sample of writing was done using the same type of pen.

Question 43

The periodic table of elements

Answer 43

Is a systematic classification of all the elements arranged in order of their atomic number(Z). The simplest element, hydrogen, has an atomic numbers for 1. It is followed by helium with atomic number 2.