General Chemistry Midterm Review

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Questions and Answers

What best describes the arrangement of atoms or molecules in a solid?

Atoms or molecules are loosely packed and have a random arrangement

Atoms or molecules are widely spaced and move freely

Atoms or molecules are in a state of constant motion with no fixed structure

Atoms or molecules are close together and may form a crystal structure (correct)

Which statement about liquids is correct?

Liquids are less dense than solids

Liquids have a fixed shape and cannot flow

Liquids can take the shape of their container and are fluid (correct)

Liquids have a higher atom arrangement than gases

How does gas differ from solids and liquids?

Gases consist of closely packed molecules

Gases expand to fill their container with large distances between molecules (correct)

Gases have a fixed volume and shape

Gases can only exist at low temperatures

What is the primary focus of chromatography as a separation technique?

It separates compounds based on their tendency to adhere to surfaces Signup and view all the answers

Which of the following statements accurately defines the International System of Units (SI)?

It is a modern metric system for measuring various properties of matter Signup and view all the answers

Which type of mixture can be distinguished by the varying composition throughout its parts?

Heterogeneous mixture Signup and view all the answers

Which process is most suitable for separating a solid from a liquid in a heterogeneous mixture?

Filtration Signup and view all the answers

In fractional distillation, which property is primarily exploited to separate the components?

Volatility Signup and view all the answers

What type of mixture is formed when a solid is dispersed in a liquid but not fully dissolved?

Suspension Signup and view all the answers

Which mixture represents a homogeneous composition throughout?

Air Signup and view all the answers

What process describes the separation of ink into its components on paper?

Chromatography Signup and view all the answers

Which of the following best describes an aerosol?

A liquid dispersed in a gas Signup and view all the answers

Which of the following is a characteristic of homogeneous mixtures?

Uniform composition throughout Signup and view all the answers

What is the primary distinction between a physical change and a chemical change?

A chemical change results in new substances, while a physical change does not. Signup and view all the answers

Which of the following is an example of a physical property?

Malleability of copper. Signup and view all the answers

What defines a pure substance in the context of chemistry?

A substance with a fixed composition that remains uniform throughout. Signup and view all the answers

What is the role of IUPAC in the classification of elements?

To identify and define established chemical elements. Signup and view all the answers

What is a characteristic of chemical compounds?

Their properties differ from the elements that make them. Signup and view all the answers

When a substance undergoes a chemical change, which of the following is true?

It creates new substances with distinct compositions. Signup and view all the answers

Which statement about physical properties is accurate?

They do not alter the substance's composition. Signup and view all the answers

In the context of matter, what defines its mass?

The amount of substance present. Signup and view all the answers

Study Notes

Course Information

Course title: General Chemistry
Instructor: Assoc. Prof. Kadriye Kizilbey
Email: [email protected]
Textbook: General Chemistry, Principles and Modern Applications (10th Edition) by Ralph Petrucci, Jeffry Madura, F. Herring, and Carey Bissonnette

Course Content

Week 1 (Oct 4): Introduction (Matter: Its Properties and Measurement)
Week 2 (Oct 11): Atoms, Molecules, and Ions
Week 3 (Oct 18): Chemical Compounds
Week 4 (Oct 25): Chemical Reactions
Week 5 (Nov 1): Reactions in Aqueous Solutions
Week 6 (Nov 8): Gases
Week 7 (Nov 15): Midterm Exam
Week 8 (Nov 22): Thermochemistry
Week 9 (Nov 29): Electrons in Atoms & Chemical Bonding
Week 10 (Dec 6): Liquids and Solids, Their Physical Properties
Week 11 (Dec 13): Chemical Kinetics
Week 12 (Dec 20): Chemical Equilibrium
Week 13 (Dec 27): Acids and Bases
Week 14 (Jan 3): (Course content not specified)

1. Purpose of Chemistry

Chemistry is the study of matter, including everything around us.
It's a crucial part of everyday life and many scientific fields.
Called the "central science" due to its connections to many other areas.
Chemists develop new materials (e.g., electronic devices like solar cells), and pharmaceuticals (e.g., cancer or viral disease drugs).

1-1 Scientific Method

What differentiates science from other fields is the specific method scientists employ to obtain and apply knowledge.
Scientific knowledge explains phenomena and can predict future events.
The scientific method combines: observation, experimentation, hypothesis formulation, law formulation, and theory development.
Hypothesis: A tentative explanation
Theory/Model: An amplified hypothesis with predictive power
Experimental results may cause a hypothesis to be revised or a theory to be modified.

1-2 Properties of Matter

Chemistry involves the composition and properties of matter.
Matter occupies space, has mass, and inertia (resistance to change in motion).
Composition: The components of matter and their relative amounts within a substance (e.g., water is 11.19% hydrogen and 88.81% oxygen by mass).
Properties of matter can be grouped into physical and chemical properties.

Physical Changes and Properties

A physical change affects properties but not the substance's composition.
Physical property: A property that does not change the substance's composition (e.g., color, malleability).
Examples of physical changes include melting, freezing, and dissolving.

Chemical Changes and Properties

A chemical change or reaction alters the composition of matter. The product is a new substance.
Chemical property describes the ability of a substance to change its composition under specific conditions.
The burning of paper is an example of a chemical change.

1-3 Classification of Substances

Matter is composed of atoms.
Substances formed by a single type of atom are elements (120 elements currently recognized).
Substances formed by two or more different atoms are chemical compounds (scientists have identified millions).
A molecule is the smallest unit of a compound that retains its composition. For example, water (H₂O) is a three-atom molecule.

1-4 Measurement of Matter: SI (Metric) Units

Chemistry is quantitative. Measurement comparisons to known standards (values).
The International System of Units (SI) is the modern form of the metric system, based on the meter (m) for length.
The speed of light in a vacuum is now a fundamental constant (exactly 299,792,458 m/s).
Quantitative data are measurable, countable, or numerical.

Units

Basic SI Units: length (meter), mass (kilogram), time (second), temperature (Kelvin), amount of substance (mole), electric current (ampere).
Derived units are combinations of basic SI units (e.g., force, pressure, energy)
Non-SI units, such as the angstrom, liter, calorie.

1-5 Density

Density is the mass per unit volume (mass/volume or g/mL).
Chemists generally use grams for mass and cubic centimeters or milliliters for volume.
Typically, solids are denser than liquids, and both are denser than gasses.

1-6 Uncertainties (Accuracy and Precision)

Precision: The consistency of measurements.
Accuracy: The nearness of measurements to a true value.
Errors in measurements can arise from the measuring instrument or the technique (or a combination).
Systematic Errors (Consistent and predictable in direction of error)
Random Errors (Varied, unpredictable, sometimes from human skill)

1-7 Significant Figures

Express numbers correctly.
Standard notation differs in Europe and the USA.
Rules for significant figures in calculations. Numerical precision depends on the number of significant figures.

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Description

Prepare for the Midterm Exam in General Chemistry with this quiz. It covers essential topics from the first half of the course, including matter, atoms, molecules, chemical reactions, and more. Test your understanding and readiness for the exam with these key concepts.