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This article introduces the study of chemistry, including the composition, structure, properties, and reactions of matter. It covers key concepts such as atoms, elements, molecules, compounds, and chemical reactions. The article also explores the physical and chemical properties of matter and provides safety precautions for conducting experiments.
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chemistry: (kĕm'ĭ-strē) n.The study of the composition, structure, properties, and reactions of matter (everything that makes up the universe).
Standards • Physical Sciences: • Elements & their combinations account for all the varied types of matter. • Chemical reactions cause atoms to rearrange forming new products w/properties • All matter is made of atoms – which may combine to make molecules. • Elements are organized on the periodic table by their chemical properties. • Instruments can create images showing atoms/molecules are discrete/ordered • Differences in chemical/physical properties of substances are used to separate mixtures & identify compounds. • Know the properties of atoms and molecules such as sugar (C6H12O6) water (H20) helium (He) oxygen (O2) nitrogen (N2) & carbon (CO2) and salts like NaCl. • Living organisms & most materials are made up of just a few elements. • Metals of the periodic table have properties in common such as electrical/thermal conductivity. Metals that are pure include Al, Fe, Ni, Cu, Ag, Au. Steel, brass, etc. are formed by a combination of elements. • Life Sciences: • Know the circulatory route of blood through the heart, lungs, body, & how CO2/O2 are exchanged in the lungs/tissues. • Plants use carbon dioxide (CO2) and water (H2O) – respiration • Plants use carbon dioxide & energy from sunlight to build sugar/release oxygen. • Earth Sciences: • Water on Earth moves between the oceans & land through the processes of evaporation & condensation (water cycle, states of matter, phase changes) • Most of Earth’s water is salt water in the oceans and when liquid water evaporates, it turns into vapor – can reappear as a liquid or a solid (melting and freezing points/physical properties of matter) • The Sun is the central body in the solar system made mostly of H and He. • Language Arts • Know abstract, derived roots/affixes from Greek/Latin to analyze word meaning • Understand how text features make info. accessible and usable. • Create multi-paragraph expository compositions • Frame questions to direct an investigation and give oral presentations
Vocabulary • Atom: the smallest portion an element can be divided into and still retain the elements properties. The smallest unit of matter. • Nucleus: • Proton: positive charged particle in nucleus • Neutron: neutral charged particle in nucleus • Shell: around nucleus w/ electrons • Electron: negative charged particle on shell • Element: matter that can’t be broken down by a chemical reaction into a simpler unit. • Molecule: exists independently consisting of one or more atoms held together by chemical bonds • Compound: combination of two or more elements • Chemical Reaction: to change the molecular composition of a substance by changing how the atoms are attached/bonded. • Physical Properties: how an element or molecule looks, smells, feels, sounds, or tastes.
Columns and Rows • Periods – elements in a row with the same # shells and element #3 comes before #4… Atomic number = # of protons • Groups – elements in a column – metals, noble gas…
Physical Properties of Matter How an element looks, feels, smells, sounds, or tastes that includes: • Color, transparency, metallic, magnetic • Conductor of electricity • Boiling and Freezing Points – the temperature at which the element goes through a phase change from a gas to a liquid to a solid (e.g.: H20 = 32o F or 0o C Freezing Point).
H2O Physical Properties Colorless Transparent Tasteless Odorless Conducts electricity Freezing Point =32oF or 0oC Boiling Point = 212oF or 100oC
*****Safety Memo***** Chemistry is exciting for students and many times the matter used in the elementary classroom may be found at home. Please advise students that these experiments have been carefully created for their health (reactions and new products are known). PLEASE DO NOT MIX MATTER AT HOME WITHOUT AN ADULT’S SUPERVISION AND A RECIPE FROM A REPUTABLE SOURCE. Many families do not know that ammonia mixed with Clorox releases deadly gas. Also, many glues when mixed with salts release deadly gas. The “Flubber” experiment – Boraxo + Elmer’s Glue - should not be used with other glues.
Evidence of a Chemical Reaction • Color change • Temperature change • Gases released • New product created with new physical properties
Molecules to Know • NaCl – table salt – solid on Earth, crystalline cubes, white, … • H20 – water • O2 – oxygen we breathe – gas on Earth, odorless, tasteless, colorless • CO2 – carbon dioxide – we breathe out • FeO2 – iron oxide (rust) – orange, solid, … • C6H12O6 – sugar – crystalline, white,…
Carbohydrates or Sugars • The word (carbo)(hyd)rate comes from the fact that glucose is made of carbon and water (carbon, hydrogen and oxygen). The chemical formula for glucose is: C6H12O6 • There are "carbohydrates" and "complex carbohydrates." The simplest carbohydrate is glucose. Glucose, also called "blood sugar" flows in the bloodstream so that it is available to every cell in your body. Your cells absorb this sugar and convert it into energy for the cell. This energy is stored in the cells mitochondria.
Carbohydrates or Sugars are all C6H12O6 but their atoms bond differently. They include: Fructose - the main sugar in fruit, Sucrose, also known as "table sugar," lactose - found in milk, and so on. The suffix – ose means “full of” Glucose and fructose are monosaccharide or one “sugars”. Lactose, sucrose and maltose are disaccharides - containing two “sugars”. These are called simple carbohydrates and they enter our blood stream at about 30 cal/min. Physical property: they all taste sweet. Glucose is colorless. When you look at a "Nutrition Facts" label on a food package and see "Sugars" under the "Carbohydrates" section of the label, these simple sugars are what the label is talking about. Complex carbohydrates (starches) made up of “chains of glucose molecules”. Starches are the way plants store energy. Most grains (wheat, corn, oats, rice) and vegetables like potatoes are high in starch. Your digestive system breaks these carbohydrates has to back down these molecules before the glucose can enter your bloodstream. This takes time. They enter the blood stream at 2 calories per minute.
Plants make starches through a process called photosynthesis. They take in CO2 through their leaves and H2O. Chlorophyll and sunlight create a chemical reaction that releases O2 andcreates sugar.
GEMS – Chemical Reactions • Materials: • Road salt – CaCl2 • Baking soda – NaHCO3 • Phenol Red – C19H14O5S • Steps to Inquiry Process: • Perform physical property assessment on each individually • Pour solids into baggy. Pour liquid and seal quickly • Make observations – temperature & color change, gases released… • Look at new product – chalk, sulfur gas, salt, water At list of literature to read post experiment is located at the following link: http://www.lhsgems.org/ChemReactConx.html
Matter, Matter Everywhere The following are extensions for the classroom: • Bring to class product labels – cereal, empty vitamin or cleaner bottles, … Read chemicals • Other show and tell: bring matter from home that can’t be found at school (appropriate) • Internet Studies– www.chem4kids.com or District site • Create a paper water molecule and “bond” 2 H’s to O (Mickey Mouse ears) • Create an element poster with that element’s physical properties, what it chemically reacts with and what’s the new product. Attach items made with that element to poster.
Assessments • Element Posters – including physical properties and other elements they chemically combine with to create what new product • Advertisements for an atom/compound • Talks/Grand Conversations on discoveries • Element Narrative: “A Day in the Life of Oxygen” that includes it’s physical properties and reactions • Chemical Reactions worksheet with observations and conclusions • Edusoft – Chemistry