Introduction to Chemistry

• Chemistry examines matter, its properties, and its transformations.
• Matter possesses mass and occupies space.
• Properties like color, density, and flammability characterize matter.
• Chemistry facilitates an understanding of our surroundings.
• Chemistry aids the development of new products and technologies.
• Chemistry helps address challenges in medicine, agriculture, and environmental science.
• The scientific method is a systematic approach to acquiring knowledge.
• The scientific method starts with observation and forms a hypothesis.
• A hypothesis provides a testable explanation for an observation.
• Hypotheses are tested through experimentation.
• Experiments yield data.
• Data analysis determines if the hypothesis is supported or refuted.
• A supported hypothesis may become accepted as a theory.
• A scientific law describes a natural phenomenon that consistently holds true.
• Chemistry relies on quantitative measurements.
• Measurements use various units.
• The SI system is the standard set of units in science.
• SI units include meter (m) for length, kilogram (kg) for mass, second (s) for time, kelvin (K) for temperature, and mole (mol) for substance amount.
• A derived unit is defined using other units.
• Volume, a derived unit, measures the space a substance occupies.
• Density, a derived unit, is the mass per unit volume.
• Temperature reflects the average kinetic energy of atoms/molecules.
• Celsius, Fahrenheit, and Kelvin are three common temperature scales.
• The Celsius scale uses water's freezing and boiling points as references.
• The Fahrenheit scale uses the freezing and boiling points of a salt solution as references.
• The Kelvin scale is an absolute temperature scale, starting at absolute zero.
• Absolute zero represents the lowest possible temperature.
• The relationship between Kelvin and Celsius is: K = °C + 273.15.
• Measurement uncertainty indicates inaccuracy or imprecision.
• Accuracy reflects how close a measurement is to the true value.
• Precision indicates the closeness of repeated measurements.
• Significant figures include certain digits plus one uncertain digit.
• Significant figures depend on the measuring instrument's precision.

Rules for Significant Figures:

• All non-zero digits are significant.
• Zeros between non-zero digits are significant.
• Leading zeros are not significant.
• Trailing zeros after the decimal point are significant.
• Trailing zeros in whole numbers without a decimal point are not significant.
• Scientific notation expresses very large or small numbers.
• A number in scientific notation is written as coefficient x 10exponent.
• The coefficient is between 1 and 10.
• The exponent is an integer.
• Dimensional analysis converts between units.
• Dimensional analysis uses conversion factors to change units.
• A conversion factor is a ratio equal to 1.
• Units in the conversion factor cancel, resulting in the desired units.

Chemistry is the study of matter and its properties, as well as how matter changes. It helps us understand the world around us and is used in various fields like medicine and environmental science. The scientific method is used to gather knowledge.