Have you ever attended a lecture and attempted to stay awake but failed? Sometimes this failure can be attributed to a lecture with no visuals. We usually use pictures, diagrams, and graphical representations to facilitate learning and understanding. In this way, particulate models aid researchers, students, and particularly chemists in understanding different types of reactions, mixtures, etc.
First, we’ll go over what a particulate model is.
Next, we’ll go over the characteristics a particular model has.
Then, we’ll talk about what particulate diagrams are.
After, we’ll go over examples of particulate diagrams in chemistry.
Lastly, we’ll talk about how particulate models are applied.
Particulate Model definition
Let's start by looking at the definition of particulate model.
The particulate model is a model that uses symbols, usually shapes, to represent atoms, ions, particles, and even states of matter. This improves our understanding, as we can use particulate models to visualize what we can't see with our own eyes.
For example, particulate models are also important when it comes to molecules. This is because molecules are 3D objects that can rotate, allowing them to take up different shapes. In other words, particulate models help us visualize all the shapes and how the configuration of a molecule can affect its reactivity.
States of matter refer to solids, liquids, and gases.
Figure 1: Particulate Models of the States of Matter. Daniela Lin, Vaia Originals.
You can use particulate models to show how atoms behave in a solid, liquid, or gas as shown above. The illustration in figure 1 is a particulate model because we’re representing solid, liquid, and gas particles as very small solid spheres.
This is because kinetic energy is related to temperature or thermal energy.
When you heat up a solid or liquid water at higher temperatures, you eventually get to gas.
Gas atoms move at faster speeds when compared to liquid atoms, which are closer together, and much faster than solid particles, which simply vibrate in place.
For more information regarding the states of matter, please visit our article “Solids, Liquids, and Gases.”
Particulate models can also refer to elements and compounds. An example of this is in the image below:
Figure 2: Particulate Models of atoms, elements, and compounds. Daniela Lin, Vaia Originals.
The atoms, elements, and compounds in figure 2 are represented by solid spheres. Note, that hydrogen and oxygen exist as molecules, hence the multiple circle representation.
Characteristics of the particulate model
Particulate models share certain commonalities, and we must know them in order to draw them correctly:
The symbols, usually shapes, represent parts of atoms, molecules, compounds, etc.
The equations must be balanced in their stoichiometric quantities for both reactants and products.
We draw particulate models as they are graphical representations and simplifications of chemical reactions.
Particulate diagrams in chemistry
Now, let's explore particulate diagrams in chemistry.
A particulate diagram shows the reaction mixture before and after the reaction has occurred, using symbols from a particulate model.
Particulate diagrams are usually more complex than particulate models, which use small spheres to represent simple non-mixtures. Note, that the terms are often used interchangeably. It’s just that particulate diagrams are often more complex than particulate models, as shown below.
Particulate Diagrams of Chemical Reactions
Consider the following reaction:
$$2NaOH (aq) + MgCl_2 (aq) \longrightarrow 2NaCl (aq) + Mg(OH)_2 (s)$$
1. Is the equation balanced?: Yes
2. Now we draw the reactants in a particulate diagram:
Figure 3: Reactants shown for the particulate diagrams of chemical reactions. Daniela Lin, Vaia Originals.
3. Now we draw products: (Notice that magnesium hydroxide, Mg(OH)2, has precipitated out of solution).
Figure 4: Products shown for the particulate diagram of chemical reactions. Daniela Lin, Vaia Originals.
Chemical mixtures and equations can be represented with multiple symbols/shapes instead of just one type. Note, that this reaction involves sodium hydroxide (NaOH) and magnesium chloride, and it’s more complex than the models shown before it.
Particulate Model examples
Now, that we know what particle models and diagrams look like. We can go over more examples to ensure that we understand how to exactly draw them. We can follow some easy steps to make sure that we have a systemic way of drawing them for simplicity:
If it's not an equation, make sure our representations are easy to work with, such as one circle representing an atom instead of a whole atomic diagram.
Make sure the equation we’re working with is always balanced.
Draw the stoichiometric quantity of the reactants.
Draw the stoichiometric quantity of the products.
Make sure if it’s a solution to draw the aqueous solution and the solids.
Draw an ionic solid particulate model of NaCl (sodium chloride):
Figure 5: Particulate Models of ionic solids like sodium chloride shown. Daniela Lin, Vaia Originals
Sodium Chloride or table salt is represented by circular shapes. Sodium is smaller because the increasing protons (+) pull electrons closer together.
Draw a compound reaction particulate model of methane and water reacting together to form carbon monoxide and hydrogen gas:
\(CH_4 (g) + H_2O (g) \longrightarrow CO (g) + 3H_2 (g)\)
1. Is the equation balanced?: Yes
2. Draw reactants:
Figure 6: Particulate Model of methane and water shown. Daniela Lin, Vaia Originals.
3. Draw products:
Figure 7: Particulate Model of carbon dioxide and hydrogen gas. Daniela Lin, Vaia Originals.
The reactant and product of our methane and water reaction are represented by symbols. Note, that hydrogen exists as a covalent molecule, hence the double circle representation.
Draw an aqueous solution particulate diagram of sodium chloride and silver nitrate together to form silver chloride and sodium nitrate:
\(NaCl (aq) + AgNO_3 (aq) \longrightarrow AgCl (s) + NaNO_3 (aq)\)
1. Is the equation balanced?: Yes
2. Draw Reactants:
Figure 8: Reactants shown for the particulate diagrams of chemical reactions. Daniela Lin, Vaia Originals.
3. Draw Products:
Figure 9: Products shown for the particulate diagram of chemical reactions. Daniela Lin, Vaia Originals.
The chemical reaction involves sodium chloride (NaCl) and silver nitrate, which we represent as circular symbols. Note, that AgCl is a precipitate.
For more information regarding particulate models of reactions, please visit our article “ Particulate Models of Reactions.”
Particulate model applications
After understanding how to draw particulate models and diagrams of reactions, ions, elements, compounds, and other particles, we should move on to applying them to real-world situations. Meaning, we should understand what we really use particulate models for. We use particulate models to explain real-world reactions and to represent solutions. In other words, we use particulate models to visualize chemical reactions.
In the real-world, scientists use particulate models to simulate gas phase processes.
This is because particle sizes of different chemicals can be an important measure of product quality. This signifies that we can draw particulate models of different symbols and shapes to show what the final product should look like.
For instance, the spray granulation process takes water-containing solutions or liquids and turns them into granules. We make granules to ensure uniform mixtures and to avoid powder segregation.
Powder segregation occurs when particles in mixed powders tend to separate based on size and other physical properties such as volume or shape. Resulting in a poor product in commercial settings, such as pharmaceutical settings.
Figure 10: Powder segregation shown. Daniela Lin, Vaia Originals.
A picture of powder segregation is shown above. Notice the clumped powder clustering based on different sizes, with the bigger clusters on top and the smaller ones on the bottom.
You’ve reached the end of this article. By now, you should understand what particulate models and diagrams are, how to draw them, and how it can be applied to the real world. Keep in mind that particulate models and diagrams, can differ in complexity, shapes, or even symbols depending on the situation we’re dealing with.
For more practice, head over to the flashcards associated with this article!
Particulate Model - Key takeaways
A particulate model is a model that uses symbols, usually shapes, to represent atoms, ions, particles, and even states of matter.
Particulate diagrams are similar to particulate models, except it involves using symbols to represent reactions that involve elements, compounds, and mixtures.
References
- Skillas, G., Becker, C., Verduyn, M., & Vorholz, J. (2007, September 2). Application of particulate models for Industrial Processes. Computer Aided Chemical Engineering.
- Hogg, R. (2014, March 29). Mixing and segregation in powders: Evaluation, mechanisms and Processes. KONA Powder and Particle Journal.
- Sanderson, A. (2019, July 29). The mechanism of granulation - formation and methods. Tablet Presses.
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