Chem Notes for Mid-term PDF

I. MATTER AND ENERGY Today, we will be able to... Define “matter” Identify different types of matter Distinguish between mixtures and Compounds UNDERSTANDING MATTER Chemistry is the study of matter, Which is the PHYSICAL material of the universe that has MASS and VOLUME,...

I. MATTER AND ENERGY Today, we will be able to... Define “matter” Identify different types of matter Distinguish between mixtures and Compounds UNDERSTANDING MATTER Chemistry is the study of matter, Which is the PHYSICAL material of the universe that has MASS and VOLUME, Like the desk, air, and our bodies. Chemistry focuses on the composition of matter and how it changes. Scientists have explored what makes up everything, from Earth to the stars, Concluding there are about 100 fundamental building blocks (atoms) Atoms, the building blocks of All matter is made of even smaller particles. Modern models of matter are based on thousands of years of scientific thinking And experiments..WHAT'S THE DIFFERENCE? HOMOGENEOUS Appears uniform throughout with no Distinguishable parts. Example: Pure water or Sugar dissolved in water. Particles are evenly Distributed. HETEROGENEOUS It has visibly different parts. With varied compositions. Example: Chocolate chip Cookie or concrete. Different parts have distinct chemical and Physical properties. MATTER INTO CATEGORIES Matter is categorized into:  Pure substances (always Homogeneous). Mixtures (can be either Homogeneous or heterogeneous). WHAT'S THE DIFFERENCE? Properties of Matter Physical Properties The quality or condition of a substance that can be observed or measured without changing the substance’s chemical composition These are the CONSTANTS About a substance. Chemical Properties Lead to changes in the identity and chemical Composition of a substance. Include behaviors that Substances adhere to when They REACT with other Substances. WHAT'S THE DIFFERENCE? PHYSICAL PROPERTY melting/freezing point boiling point color texture conductivity solubility odor appearance and many more CHEMICAL PROPERTY heat of combustion reactivity with water  flammability reactivity with an acid reactivity with oxygen PURE SUBSTANCES Pure Substance: Matter with uniform Composition throughout. Includes elements and Compounds. ex) Oxygen gas (O₂) - element ex) Water (H₂O) - compound Elements Elements are substances that cannot be broken down or decomposed into simpler Substances by chemical means. 91 naturally occurring elements, Others synthesized in labs. Most elements are metals, such as gold, iron, and aluminum Compounds Composed of two or more elements that are chemically combined in definite proportions By mass. Although all compounds contain at least two different types of atoms, the composition of a The compound is the same throughout. Follows the Law of Definite Proportions: the statement that types of atoms in a Compound exists in a fixed ratio. Example: Water (H₂O) is always 2 parts Hydrogen to 16 parts oxygen by mass. EXAMPLE: DECOMPOSITION OF WATER: 18 g H₂O → 16 g O₂ + 2 g H₂. Mixtures Are combinations of two or more Pure substances that can be separated by Physical means. Unlike compounds, mixtures do not. Have a definite or “fixed” composition. The parts can be separated by physical means. Example: Different amounts of sugar can be dissolved in water, and the Sugar can be separated by Evaporation. Solutions are homogeneous mixtures. Today, we will be able to... Define mixtures Distinguish between mixtures and compounds Apply knowledge of mixtures to real-world scenario Mixtures vs. Compounds Both mixtures and compounds contain two or More elements, but they differ in composition and Properties. Mixtures: Elements can be present in varying Ratios. Each element retains its own Properties. Can be separated by physical Means (e.g., using a magnet). Compounds:  Elements chemically combine in fixed ratios (e.g., 1.74 parts iron to 1.00 part sulfur). The compound has new. properties, distinct from the Original elements. Mixtures: Ex) Iron and sulfur in a mixture—Iron remains magnetic, and Sulfur keeps its yellow color. Can be separated by physical Means (e.g., using a magnet). Compounds: Ex) Iron sulfide has a different melting point and loses the the magnetic properties of iron and The color of sulfur. Today, we will be able to... Define elements and mixtures. Explain the difference between physical and chemical properties Apply knowledge of science to real case scenario SEPARATION OF MIXTURES Mixture components can be separated based on their properties, such as density, molecular polarity, freezing point, Or boiling point. Three different techniques that can be used to separate the components of mixtures ○ Filtration ○ Distillation ○ Chromatography FILTRATION Used to separate two components of a mixture Solid from a liquid - when the solid is Suspended, not dissolved. ○ Solid particles are trapped by a filter, while the liquid (filtrate) Passes through.  Filter: a material containing holes; that allows small particles to pass through while trapping larger particles on or in the filter material not dissolved = not a homogeneous mixture SEPARATION OF IMMISCIBLE LIQUIDS: Immiscible liquids (e.g., oil and water) do not dissolve in each other. Separating immiscible liquids: Can be separated by density using a separatory funnel, allowing the denser liquid to flow out from the bottom.