PROPERTIES OF MATTER
What is the difference between intensive and extensive properties?
The difference between intensive and extensive properties is that intensive properties do not depend on the amount of matter (e.g., density, temperature), while extensive properties do (e.g., mass, volume).
What is the significance of groups on the periodic table?
Groups on the periodic table indicate elements with similar chemical properties and the same number of valence electrons.
What is a covalent bond?
A covalent bond is formed when two nonmetals share electrons.
What is the definition of an element?
An element is a pure substance consisting of only one type of atom, such as gold (Au).
What is a physical property?
A physical property is a characteristic that can be observed without changing the substance’s chemical identity (e.g., melting point).
Which type of property is density: intensive or extensive?
Density is an intensive property.
Name the period and group for Sodium (Na) on the periodic table.
Sodium (Na) is in period 3 and group 1 (alkali metals).
Give an example of an ionic compound and explain how it forms.
An example of an ionic compound is sodium chloride (NaCl), formed when sodium donates an electron to chlorine.
Differentiate between a compound and a mixture.
A compound consists of two or more elements chemically bonded together in a fixed ratio, while a mixture contains two or more substances that are physically combined and can vary in composition.
Name two examples of chemical properties.
Examples of chemical properties include reactivity with water and flammability.
Identify two examples of physical properties and two examples of chemical properties.
Examples of physical properties include color and boiling point. Examples of chemical properties include reactivity with acids and flammability.
Write the electron configuration for Carbon (C).
The electron configuration for Carbon (C) is
Draw a Lewis dot structure for a molecule of water (H₂O).
The Lewis dot structure for a molecule of water (H₂O) shows the oxygen atom in the center with two pairs of electrons shared with two hydrogen atoms.
Is air a compound, element, homogeneous mixture, or heterogeneous mixture? Explain.
Air is a homogeneous mixture of gases, as its composition is uniform throughout.
How can you tell the difference between a chemical change and a physical change?
A chemical change results in a new substance being formed (e.g., burning paper), while a physical change affects the state or form of a substance but not its composition (e.g., melting ice).
Explain why mass is considered an extensive property.
Mass is considered an extensive property because it depends on the amount of matter present in a sample.
Explain why elements in the same group have similar chemical properties.
Elements in the same group have similar chemical properties because they have the same number of valence electrons, which determine bonding behavior.
Describe how electrons are shared or transferred in covalent and ionic bonds.
In covalent bonds, electrons are shared between atoms, while in ionic bonds, electrons are transferred from one atom to another.
Describe the differences between a homogeneous mixture and a heterogeneous mixture, with examples.
A homogeneous mixture has a uniform composition throughout (e.g., saltwater), while a heterogeneous mixture has distinct regions (e.g., a salad).
Describe how reactivity is a chemical property and provide an example.
Reactivity is a chemical property that describes how a substance interacts with others to form new compounds. For example, potassium reacts vigorously with water.
Describe a scenario in which observing a chemical property leads to a chemical change.
A scenario where observing a chemical property leads to a chemical change is when iron rusts after exposure to oxygen, demonstrating reactivity.
Provide the electron configuration for an element with atomic number 17 (Chlorine) and describe its reactivity.
Chlorine (atomic number 17) has the electron configuration. It is highly reactive as it needs to gain one electron to achieve a stable octet.
Compare the melting points and solubility properties of ionic vs. covalent compounds.
Ionic compounds generally have higher melting points and are more soluble in water compared to covalent compounds because of the strong electrostatic forces between ions.
Explain why separating compounds requires a chemical change but separating mixtures does not.
Separating compounds requires a chemical change to break the bonds between elements, whereas mixtures can be separated by physical methods like filtration or distillation.
Explain why boiling water is a physical change, even though it involves changing states.
Boiling water is a physical change because it changes the state of water from liquid to gas without altering its chemical composition.