Questions and Answers
What are two different ways to classify matter?
Pure Substance or Mixture
How do solids, liquids, and gases differ?
Solids have fixed particles and strong bonds, liquids have closely packed particles that can flow, gases have widely spaced and compressible particles.
Explain the difference between a pure substance and a mixture based on the composition of each.
A pure substance has only one type of particle; a mixture contains two or more particles in varying proportions.
Explain the difference between an element and a compound.
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Explain the difference between a homogeneous and a heterogeneous mixture.
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Describe the scientific approach to knowledge. How does it differ from other approaches?
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Explain the differences between a hypothesis, a law, and a theory.
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What observations did Antoine Lavoisier make? What law did he formulate?
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What theory did John Dalton formulate?
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What is wrong with the expression, 'That is just a theory,' if by theory the speaker is referring to a scientific theory?
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Summarize the history of the atomic idea. How was Dalton able to convince others to accept an idea that had been controversial for 2000 years?
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State and explain the law of conservation of mass.
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State and explain the law of definite proportions.
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State and explain the law of multiple proportions. How is this different from the law of definite proportions?
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What are the main ideas in Dalton's atomic theory? How do they help explain the laws of conservation of mass, of constant composition, and of definite proportions?
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How and by whom was the electron discovered? What basic properties of the electron were reported with its discovery?
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Explain Millikan's oil drop experiment and how it led to the measurement of the electron's charge. Why is the magnitude of the charge of the electron so important?
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Describe the plum pudding model of the atom.
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Describe Rutherford's gold foil experiment. How did the experiment prove the plum pudding model of the atom was wrong?
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Describe Rutherford's nuclear model of the atom. What was revolutionary about his model?
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If matter is mostly empty space, as suggested by Rutherford, then why does it appear so solid?
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List the three subatomic particles that compose atoms and give the basic properties (mass and charge) of each.
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What defines an element?
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Explain the difference between Z (atomic number) and A (the mass number).
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Where do elements get their names?
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What are isotopes? What is the percent natural abundance of isotopes?
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Describe the two different notations used to specify isotopes and give an example of each.
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What is an ion? What is a cation? What is an anion?
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What is atomic mass? How is it calculated?
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Explain how a mass spectrometer works. What kind of information can be determined by a mass spectrum?
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Study Notes
Classification of Matter
- Matter can be classified as either a Pure Substance or a Mixture.
- Pure substances consist of only one type of particle, while mixtures consist of varying proportions of two or more particles.
States of Matter
- Solids: Fixed particles that can only vibrate; have strong intermolecular bonds.
- Liquids: Closely packed particles that can move, allowing them to take the shape of their container.
- Gases: Widely spaced particles that are compressible and can flow freely.
Pure Substances vs. Mixtures
- Pure Substance: Consistent composition and properties, can be an element or compound.
- Mixture: Composition can vary between samples, can be homogeneous or heterogeneous.
Elements vs. Compounds
- Element: Cannot be broken down into simpler substances through chemical means.
- Compound: Consists of two or more different elements that are chemically combined.
Homogeneous vs. Heterogeneous Mixtures
- Homogeneous Mixture: Uniform composition throughout, such as sweetened tea.
- Heterogeneous Mixture: Composition varies, such as water mixed with sand.
Scientific Approach to Knowledge
- The scientific method emphasizes empiricism, observation, and experimentation to understand natural phenomena.
Hypothesis, Law, and Theory
- Hypothesis: A testable prediction about the relationship between variables.
- Law: A statement that describes a consistently observed phenomenon.
- Theory: An explanation based on a body of evidence that encompasses multiple hypotheses.
Antoine Lavoisier's Observations
- Lavoisier demonstrated the conservation of mass, formulating the Law of Conservation of Mass, which states that mass is neither created nor destroyed in chemical reactions.
John Dalton's Atomic Theory
- Dalton proposed that atoms are indivisible and combine in simple whole-number ratios to form compounds.
Scientific Theory Misconception
- The phrase "That is just a theory" misunderstands scientific theory, which is a well-substantiated explanation based on evidence.
History of Atomic Concept
- Dalton's atomic theory gained acceptance through rigorous experimentation and evidence backing the existence of atoms.
Law of Conservation of Mass
- States that in a closed system, the total mass remains constant during a chemical reaction.
Law of Definite Proportions
- Every chemical compound contains elements in fixed proportions, regardless of the amount of the compound.
Law of Multiple Proportions
- When two elements form multiple compounds, the ratios of the masses of one element that combine with a fixed mass of the other can be expressed as small whole numbers.
Dalton's Atomic Theory Main Ideas
- Atoms are indestructible, unique to each element, and combine in specific ratios, helping to explain conservation of mass and constant composition.
Discovery of the Electron
- Discovered by J.J. Thomson through cathode ray experiments; it has a negative charge and a very small mass relative to protons and neutrons.
Millikan's Oil Drop Experiment
- Experiment measured the charge of an electron; its significance lies in understanding atomic charge and quantization.
Plum Pudding Model of the Atom
- Proposed by Thomson, depicting the atom as a positively charged "soup" with electrons scattered throughout.
Rutherford's Gold Foil Experiment
- Disproved the plum pudding model by demonstrating that atoms have a small, positively charged nucleus.
Rutherford's Nuclear Model
- Proposed that atoms consist of a dense nucleus surrounded by electrons; revolutionary for establishing the nuclear structure in atoms.
Perception of Matter as Solid
- Despite being mostly empty space, matter appears solid due to the interactions between electrons of adjacent atoms.
Subatomic Particles
- Atoms consist of protons (positive charge, significant mass), neutrons (neutral charge, significant mass), and electrons (negative charge, negligible mass).
Definition of an Element
- An element is defined by its atomic number, which indicates the number of protons in its nucleus.
Atomic Number (Z) vs. Mass Number (A)
- Z: Number of protons in an atom's nucleus (defines the element).
- A: Total number of protons and neutrons in the nucleus.
Naming of Elements
- Elements derive their names from various sources, including Latin, mythology, or elements' properties.
Isotopes
- Atoms of the same element with different numbers of neutrons; percent natural abundance refers to the proportion of each isotope present in a natural sample.
Notations for Isotopes
- Common notations include the element symbol and mass number (e.g., Carbon-12) or isotopic notation (e.g., ^12C).
Ions, Cations, and Anions
- Ion: A charged atom.
- Cation: A positively charged ion, gained by losing electrons.
- Anion: A negatively charged ion, gained by gaining electrons.
Atomic Mass
- Represents the weighted average of an element's isotopes; calculated based on the mass and abundance of each isotope.
Mass Spectrometer Function
- A mass spectrometer analyzes ions based on mass-to-charge ratio; it provides information on the composition and abundance of isotopes.
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Description
This quiz covers key concepts from Chapter 1 of Chemistry, focusing on the classification of matter and the differences between solids, liquids, and gases. Test your understanding with these flashcards that summarize essential definitions and characteristics. Ideal for reviewing foundational chemistry concepts.
