1.1 - Chemistry: A Science for the Twenty-First Century

• Chemistry is sometimes referred to as the "core science" because pupils must have a fundamental understanding of the subject.

  • Chemistry is the study of matter and the processes that it goes through.

• Chemistry is an old subject, but its contemporary basis was formed in the nineteenth century.

• Scientists were able to break down substances into increasingly smaller components and, as a result, explain many of their physical and chemical features due to intellectual and technological advancements.

• Chemists can examine the structure of atoms and molecules, which are the fundamental units of chemistry, and create new compounds with specified features

  • Such as medications and ecologically friendly consumer goods.

1.2 - The Study of Chemistry

• Practicing chemistry also applies to cooking! Oil and water do not mix, and boiling water left on the burner evaporates, as you know from culinary experience.

• When you use baking soda to leaven bread, use a pressure cooker to cut down on cooking time, use a even though the Two types of solutes dissolve forwarding meat tenderizer in a pot roast, pour lemon juice over sliced pears to keep them from browning or over fish to reduce odor, you're using chemical and physical principles.

  • We see such changes every day without even realizing they are chemical changes.

1.3 - The Scientific Method

• The scientific method, which is a methodical approach to research, is used in all areas, including the social sciences.

  • A methodical approach to study is known as the scientific method.

• The first step is to characterize the issue thoroughly. Experiments, careful observations, and data collection are all part of the following stage.

• A research study's data can be both qualitative and quantitative, consisting of broad observations about the system and figures derived from various measurements of the system

• The next step in the scientific method is interpretation, which involves the scientist attempting to explain the observed event after the experiments have been performed and the data have been recorded.

• The researcher creates a hypothesis based on the information gathered.

  • A hypothesis is a possible explanation for a set of facts.

• Following the collection of a vast amount of data, it is frequently useful to summarize the information in a compact manner, such as a law.

  • Law is a succinct verbal or mathematical description of a constant relationship between events under constant conditions.

• The (F = ma) law states that when an object's mass or acceleration increases, so does its force, and vice versa.

• Theories can emerge from hypotheses that survive numerous experimental testing of their validity.

  • A theory is a guiding principle that explains a collection of facts and/or the laws that govern them.

• If an experiment disproves a theory, it must be rejected or adjusted to make it consistent with experimental findings.

• It can take years, even centuries, to prove or disprove a theory, in part because the essential technology may not be accessible.

1.4 - Classifications of Matter

• Things we can see and touch are considered the matter.

  • The matter is defined as anything that has mass and fills space.

  • A substance is a type of stuff with a specific composition and set of characteristics.

  • A mixture is a combination of two or more substances that retains their even thoughidentities.

• Homogeneous and heterogeneous mixtures are the two types of mixtures.

  • A homogeneous mixture has the same composition throughout.

  • The composition is not uniform, making it a heterogeneous combination.

• Elements and compounds are both examples of substances.

  • A substance that cannot be split into simpler components by chemical processes is referred to as an element.

1.5 - The Three States of Matter

• Solid, liquid, and gas are the three states in which all substances can exist in theory.

1.6 - Physical and Chemical Properties of Matter

• Both the qualities and the makeup of substances are used to identify them. Physical attributes include color, melting point, and boiling point.

  • A physical attribute of a substance can be measured and seen without affecting its composition or identity.

• The statement “Hydrogen gas burns in oxygen gas to form water” describes a chemical property of hydrogen.

  • To examine this chemical feature of hydrogen, we must perform a chemical transformation.

• All measurable qualities of matter are divided into two groups: extensive properties and intensive properties.

  • The size of an extensive property is determined by the amount of matter evaluated.

  • Mass is a broad attribute that refers to the amount of matter in a particular sample of a substance.

  • The amount of substance considered has no bearing on the measured value of an intense attribute.

  • An intensive property is a density, which is defined as the mass of an object divided by its volume.

1.7 - Measurement

• Chemists' measurements are frequently employed in computations to obtain other quantities.

  • Macroscopic qualities that can be directly determined

  • On the atomic or molecular scale, microscopic qualities can only be determined indirectly.

• The terms "mass" and "weight" are frequently interchanged, despite the fact that they are two distinct variables.

  • The force of gravity acting on an object is known as weight.

1.8 - Handling Numbers

• The last digit is assumed to be questionable when significant figures are used.

• The margin of error in a measurement is indicated using significant figures, which are the meaningful digits in a measured or calculated quantity.

1.9 - Dimensional Analysis in Solving Problems

• When solving chemistry problems, we employ dimensional analysis to convert between units.

1.10 - Real-World Problem Solving: Information, Assumptions, and Simplifications

• We don't have a thorough picture of a problem, or data isn't readily available. In these situations, we must learn to make educated guesses.

  • This method is sometimes referred to as "ball-park estimates," which are simple, quick computations that may be completed in a short amount of time.