Podcast
Questions and Answers
Which statement accurately describes the arrangement and behavior of molecules in the liquid phase of matter?
Which statement accurately describes the arrangement and behavior of molecules in the liquid phase of matter?
- Molecules have a definite volume but adopt the shape of their container, exhibiting negligible intermolecular forces.
- Molecules are tightly packed with strong intermolecular forces, maintaining a definite shape and volume.
- Molecules have indefinite shape and definite volume, with intermolecular forces stronger than gases but weaker than solids. (correct)
- Molecules are widely dispersed with negligible intermolecular forces, allowing for both indefinite shape and volume.
Which of the following is the BEST example of a chemical property?
Which of the following is the BEST example of a chemical property?
- The temperature at which a substance changes from solid to liquid.
- The state in which a substance exists at room temperature.
- The capacity of a substance to react with oxygen. (correct)
- The ability of a substance to dissolve in a solvent.
When water boils and turns into steam, what type of change occurs, and why?
When water boils and turns into steam, what type of change occurs, and why?
- A chemical change, because the total energy of the water molecules increases significantly.
- A physical change, because the water changes its state but its chemical composition (\$H_2O\$) remains the same. (correct)
- A chemical change, because the water molecules are broken down into hydrogen and oxygen gases.
- A physical change, because the heat applied only affects the impurities in the water.
Which of the following processes involves a chemical change?
Which of the following processes involves a chemical change?
Which statement accurately differentiates between a homogeneous and a heterogeneous mixture?
Which statement accurately differentiates between a homogeneous and a heterogeneous mixture?
Which of the following statements accurately describes the composition of an atom?
Which of the following statements accurately describes the composition of an atom?
How does the mass number of an atom relate to its composition?
How does the mass number of an atom relate to its composition?
How does chemistry BEST contribute to our understanding of the world?
How does chemistry BEST contribute to our understanding of the world?
A scientist observes that a solid substance melts at 85C. What type of property is the melting point?
A scientist observes that a solid substance melts at 85C. What type of property is the melting point?
Consider a scenario where hydrogen peroxide ($H_2O_2$) decomposes into water and oxygen when exposed to light. What kind of change is this, and why?
Consider a scenario where hydrogen peroxide ($H_2O_2$) decomposes into water and oxygen when exposed to light. What kind of change is this, and why?
Classify the following as either a homogeneous or heterogeneous mixture: salt water, and vegetable soup.
Classify the following as either a homogeneous or heterogeneous mixture: salt water, and vegetable soup.
How do the charges of protons and electrons compare within an atom?
How do the charges of protons and electrons compare within an atom?
Which of the following describes matter?
Which of the following describes matter?
Determine the number of protons in an atom with an atomic number of 26 and 30 neutrons
Determine the number of protons in an atom with an atomic number of 26 and 30 neutrons
If a substance has flammability as one of its characteristics, is flammability a physical or chemical property?
If a substance has flammability as one of its characteristics, is flammability a physical or chemical property?
Flashcards
Chemistry
Chemistry
The field of study concerned with the characteristics, composition, and transformations of matter.
Matter
Matter
Anything that has mass and occupies space.
Three States of Matter
Three States of Matter
Solid, liquid, and gas.
Physical Property
Physical Property
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Chemical Property
Chemical Property
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Physical Change
Physical Change
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Chemical Change
Chemical Change
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Pure Substance
Pure Substance
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Element
Element
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Compound
Compound
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Mixture
Mixture
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Heterogenous Mixture
Heterogenous Mixture
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Homogenous Mixture
Homogenous Mixture
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Electrons
Electrons
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Mass Number
Mass Number
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Study Notes
Objectives
- Chemistry, matter, the three phases of matter, physical properties of matter, changes of matter, and pure substances and mixtures are defined and differentiated.
Chemistry
- Chemistry is the detailed field of study of the characteristics, composition, and transformations of matter.
What is Matter?
- Matter is anything with mass that occupies space.
Three Physical States of Matter
- Solid: Has a definite shape and volume with highly strong intermolecular forces between the molecules.
- Liquid: Has an indefinite shape and definite volume; intermolecular forces are strong, but weaker than solids
- Gas: Has an indefinite shape and indefinite volume; intermolecular forces are practically non-existent.
Properties of Matter
- Used in identification and description, each substance has a unique set of properties that distinguishes it from all other substances.
Physical Property
- Can be observed without changing the basic identity of the substance.
- Examples of physical properties are color, odor, physical state, melting point, boiling point, and hardness.
Chemical Property
- The characteristic of a substance that describes the way the substance undergoes or resists change to form a new substance.
- Examples are flammability, decomposition (at high temperature/presence of light), and reactivity.
Changes in Matter
- Physical change: a substance changes its physical appearance but not its chemical composition; a new substance is never formed; it is the most common type; includes changes in physical state such as melting, freezing, evaporation, and condensation.
- Chemical change: a substance undergoes a change in chemical composition, converting the material(s) into one or more new substances with properties and composition distinctly different from those of original materials.
Pure Substance and Mixture
- Matter is classified by chemical composition as a pure substance or mixture
- Pure substance: single kind of matter that cannot be separated into other kinds of matter by any physical means (element or compound).
- Element – cannot be broken down into simpler substances.
- Compound - yield two or more simpler substances by chemical means
- Mixture: a physical combination of two or more pure substances where each substance retains its chemical identity (heterogenous or homogenous).
- Heterogenous – mixture that contains visibly different phases, each of which has different properties.
- Homogenous - mixture that contains only one visibly distinct phase, which has uniform properties throughout; the individual components cannot be visually distinguished.
Atomic Structure Review
- Atom structure:
- Electrons: the smallest subatomic particle.
- Protons.
- Neutrons.
- Protons and electrons share the same charge amount.
- Protons and neutrons are massive compared to electrons, almost 2000x heavier.
- Protons and neutrons are found at the center of an atom (nucleus).
- Electrons exist in the atom's outer region.
- The volume occupied by the electrons is referred to as the electron cloud.
- An atom as a whole is electrically neutral.
Atomic Mass and Atomic Number
- Mass number is the total number of protons and neutrons (symbol A).
- Atomic weight/atomic mass is the weighted average mass of an atom of an element based on the relative natural abundance of that element's isotope.
- Atomic number is the number of protons (same as number of electrons) (symbol Z).
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