Models of Matter
Why do scientists use models to study atoms and molecules?
Because atoms and molecule are too small to see directly
Which state of matter has particles packed tightly in a fixed arrangement?
Solid
What is a molecule?
Why does a solid generally maintain its own shape?
It's particles are held in fixed positions.
What is the chemical formula for water?
H2O
A model shows several atoms connected together to represent a substance. What is the model helping scientists to understand?
How the atoms are arranged or connected
Which state of matter has particles that are close together but can move and slide past each other?
Liquid
Water, H2O, is made of individual groups of atoms. Is water represented as individual molecules or one continuos structure?
Individual Molecules
Why can a liquid flow and take the shape of its container?
Its particles can move and slide past each other
How many hydrogen atoms and oxygen atoms are in one molecule of H2O?
2 Hydrogen Atoms and 1 oxygen atom
A scientists uses two different models of the same molecule. One shows the bonds clearly, while the other shows the amount of space the molecule occupies. Why might the scientists use both?
Different model shows different sides or properties of the same substance
A particle model shows particles spread far apart with no regular arrangement. What state of matter is this?
Gas
Diamond contains carbon atoms connected throughout a large repeating network. Is diamond made of individual atoms or an extended structure?
Extended Structure
Diamond is very hard. Its carbon atoms are connected in a repeating structure. What does this suggest about the relationship between structure and properties
The arrangement and connections of atoms can help determine a substances properties
A model has one carbon atom connected to four hydrogen atoms. What type of atoms are present in this molecule?
Carbon and Hydrogen Atoms
A model shows atoms as large colored spheres. A student says, "this means the atoms are actually this color and this size ." Is the student correct?
No. The colors and sizes are used to represent atoms and make the model easier to understand.
Three models shows the same substance. Model A has tightly packed particles, Model B has particles close together but randomly arranged, and Model C has particles spread far apart. Which model represents the highest temperature state?
Model C, the particles are spread far apart and represent a gas
A model shows the same small groups of atoms repeated as separate units with space between the units. What type of structure does this most likely represent?
Individual molecules
Salt forms a rigid crystal. What feature of its structure helps explain this property?
Its atoms are arranged in a repeating/extended structure
A model contains two different types of atoms bonded together in a specific ratio. Is this more likely to represent an element or a compound?
Compound
Scientist create a model showing how particles are arranged inside a crystal. They then use that arrangement to explain why the crystal has a particular shape. What does this demonstrate about models?
A substance changes from a solid to a liquid. What happens to the arrangement and movement of its particles?
The particles become less fixed and can move/ slide past each other while still being close together.
Two substances both contain atoms connected by bonds. One has separate group of atoms, while the other has atoms connected throguhout one continuous network. How would you classify the two structure?
The first is made of individual molecules; the second is an extended structure.
Imagine substance X has atoms arranged in a repeating, rigid network, while substance Y consists of small molecules that can move past each other. Predict which substance is more likely to maintain a fixed shape and explain why?
Substance X because its particles are connected in a rigid, extended structure
A student changes the number and arrangement of atoms in a model. The resulting substance has different properties. What does this demonstrate?
The types, number, and arrangement of atoms can determine the properties of a substance