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What is the best method to classify a chemical substance? - Coggle Diagram
What is the best method to classify a chemical substance?
Background Information
Bonds
Ionic Bonds
Ionic bonds are created between a non-metal and a metal, are high in polarity (physical features such as solubility) and can conduct electricity if in a solution (e.g. distilled water).
Covalent Bonds
Covalent bonds are created between two non metals and cannot conduct electricity whilst not being able to be dissolved into water due to the strength of the bonds.
Metallic bonds
Metallic bonds are created between two metals and can conduct electricity yet cannot dissolve in water due to its strength.
Substance groups
Metals
Metals conduct electricity and heat well, are malleable and ductile as well as a shiny, metallic lustre and color.
Non Metals
All non metals are brittle, cannot conduct electricity and heat whilst having a dull non-metallic appearance and lustre.
Metalloids
Metalloids share similar qualities to metals however they cannot conduct electricity as well as metals and are brittle.
What is a chemical substance?
A chemical substance is any material that has a definite chemical composition. Pure chemical substances cannot be separated into other substances by any mechanical processes. Chemical substances consist of two or more types of atoms (elements) that have been chemically bonded and reacted.
Types of mixtures
Heterogenous
A mixture made of multiple different substances which do not mix in a uniform manner whilst attaining no bonds. The mixture is very easy to separate.
Homogenous
A mixture of multiple different substances that are mixed uniformly whilst attaining no bonds. The mixture is not easily separated.
What is a compound?
A compound is a material formed by chemically bonding two or more chemical elements. Compounds can be bonded using covalent, ionic or metallic bonds.
Potential method to classify substances
Concentration of acid
How will it be measured
The concentration of acid for a certain substance will be measured using a pH measuring kit. The higher the shade of red the substance measured using the pH kit is, the higher the acid concentration. A high acid concentration will most likely mean that the substance is a non-metal
Limitations
Temperature and carbon dioxide are some factors that can affect the buffer solution needed to determine the level of acidity a certain substance has, altering the color tone. Furthermore, using personal observation can lead to errors such as misjudgment and personal bias.
Concentration of alkali
How will it be measured
The concentration of alkali for a certain substance will be measured using a pH measuring kit. The darker the shade of purple the substance measured using the pH kit is, the higher the base concentration. A high base concentration will most likely mean that the substance is a metal
Limitations
Temperature and carbon dioxide are some factors that can affect the buffer solution needed to determine the level of alkali a certain substance has, altering the color tone. Furthermore, using personal observation can lead to errors such as misjudgment and bias (e.g. wanting the substance to be more basic or acidic)
Boiling/melting point
How will it be measured
Boiling point will be measured through heating up the substance until there are visable signs that said substance is boiling. A thermometer, beaker and bunsen burner will prefrebaly be used to measure the boiling point. A substance that takes a long time to melt/boil is most likley a non-metal.
Limitations
Due to the limited tools available, it would hard to classify each substance based off boiling point due to to fact that the beaker will break before some substances (e.g.metals) start to melt
Surface area
How will it be measured
A substance's surface area will be measured through a microscope using nanometers as the unit of measurement. The surface area Surface area may affetc the rate of certain chemical reactions as well as the type of material
Limitations
Measuring surface area is limited to only solid substances. Not only that, but the given substances' surface area may've been altered beforehand and that it is difficult to classify substances based off surface area.
Solubility
How will it be measured
Solubility will be measured through placing the substance into a test tube with water. The solution will be mixed for a certain amount of time. If the solute is separated from the water or the water is cloudy, the substance is most likley a metal (metallic/ionic bond). If the solution is to some degree clear, the substance is a non-metal (covalent bond). Testing the solubility will be used i to classify chemical substances.
Limitatations
Solubility of a substance may be affected by the surrounding environment's temperature as well as the size and shape of the substance placed in the water which will most likely take longer to dissolved compared to a smaller substance.
Electric conductivity
Electricity conductivity of a substance will be measured through placing a substance into a beaker and then using an electrical conductivity measuring device. If the substance conducts electricity when in a solid state, it has a metallic bond. If the substance doesn't conduct electricity in both solid and liquid state, it has a covalent bond. If the substance conducts electricity when in distilled water but not in a solid state, it has a ionic bond. Electrical conductivity will be used to classify the chemical substances.
Malleability and sturdiness test
Malleability will be determined by looking at the substance through a microscope before and after using a hammer to break the substance. If the substance shows no sign of change, it has a metallic bond. if the substance has broken and shattered, it is an ionic bond. If the substance breaks and turned to fine pieces/dust, the substance has a covalent bond. Testing the malleability will be used in the design to determine the type of bond each substance has.
Appearance/Observation
Substances that have a metallic luster and are shiny and silvery-grey will have a metallic bond. Substances that are dull in colour will most likely have a covalent bond (non metals). Most Substances that have a ionic bond will have a crystalline-like structure when viewed through a microscope.
A limitation to the method of measuring appearance is that it is based on personal judgment and so others may have a different opinion on the bond a certain substance may have. Nevertheless, this method will be used to determine the type of bond a given substance has.
Magnetism
If a substance can be pulled using a magnet, it has a metallic bond. However, if the substance cannot be pulled by a magnet, the substance either has an ionic or covalent bond. This method will be used to determine if a substance has a metallic bond or not
Risk assessment
Emergency procedures
In the case that equipment is broken, it is important to notify others so that the situation is taken care of and no one else is affected.
In the case that equipment is broken, it is important to notify others so that the situation is taken care of and no one else is affected.
Wash hands before handling substances
Avoid drinking substances in the lab
Wear protective clothing (safety goggles, apron) to ensure that potentially harmful substances do not leave the lab
Precautions
It is important to keep in mind the surrounding environment when conducting an experiment whether it be nearby objects or students as well as ensuring that the experiment is conducted in a calm and precise manner so that the correct measurements and steps are made.
Disposal
After using the chosen methods to classify each chemical substance, it is of the utmost importance that the substance is placed into an appropriate waste bin rather than down the drain which may cause damage or waste spillage/contamination into the environment.
Potential risks:
Touching certian chemical substances may lead to burning or poisoning
Letting substances enter your eyes may cause irritation or damage
Dropping glass equipment such as a beaker can lead to open cuts which may get infected
Spilling chemical substances on the floor ,may make you and other students slip and fall
Using an electrical conductivity measurement device can lead to electrical shocks
Limitations
Environment
The environment the experiment will be conducted within may not meet the requirements to use certain methods to determine whether a substance has a covalent, ionic or metallic bond such as melting and boiling point.
It is vital to choose an environment that allows for an experiment to be carried out. Significantly spiritual and cultural sites must not be used as the chemical substances may damage the surrounding structures whilst conducting an experiment may be disrespectful to certain ethic cultural groups.
Equipment
Due to a limited range of equipment to use for the experiment, important to keep in mind that the results gathered from the methods chosen may not be accurate representations of certain substances and that generalizations based on other similar substances will have to be made without sufficient, proper equipment.
Some equipment that require the use of hazardous materials may be restricted to experiment conductors who may inexperienced or unaware of how to operate said equipment
Funding
A small funding model for the experiment may result in a limited number of materials for which the experiment cannot be conducted multiple times to enforce the validity and accuracy of the collected results. Limited funding can also create time restraints which means that the experiment cannot be done in an analytical and thorough manner.
Age/experience of experiement conductors
Some methods to determine the bond of certain chemical substances may not be suitable for inexperienced, young candidates as they may involve practices which can ultimately lead to bodily or environmental harm. It is important to choose methods which a wider range of conductors of varying ages and experience levels could also use to determine the bonds for chemical substances.
Design type
An experimental design will allow for the testing of a hypothesis as well as the inference of causality under controlled conditions to maximize validity. An experimental design proves to be be the most accurate and efficient to analyze the results regarding whether certain substances have covalent, ionic or metallic bonds so that the best method to classify a chemical substance can be deduced.
Factors that can affect substance bond classification
Different chemical substances have different physical properties which may affect classification into ionic, metallic and covalent bonded substances.
Density
Boiling and melting points
State of matter (solid, liquid, gas)
Conductivity
Solubility
Color
Chemical properties
Reactivity
Reactivity is the readiness a substance undergoes a chemical reaction. The more reactive substances can ignite spontaneously in the form of a spark or an explosion. Different chemical substances react with one another in different ways which may make it difficult to identify the type of bond a substance has.
Chemical composition
Chemical composition is the arrangement, type, and ratio of atoms in molecules of chemical substances. Chemical composition varies when chemicals are added or subtracted from a substance, when the ratio of substances changes, or when other chemical changes occur in chemicals.
