1.05 – Flashcards

elements, compounds, and mixtures of the two

mixtures and pure substances

either pure compounds or pure elements

either pure compounds or pure elements

~ substance that contains two or more elements combined in a fixed proportion ~ substance composed of two or more elements that are chemically bonded in a definite, fixed ratio by mass

~ the simplest form of matter that has unique properties and is composed of only one kind of atom ~ a chemical substance that contains only one kind of atom and that cannot be broken down into simpler substances

only one type of atom

pure substances on earth, but rather occur as parts of compounds

liquid mercury, composed only of mercury atoms, is a pure element but it is very rare in nature

more than one type of atom

two or more elements combined in a fixed proportion

~ Water (H2O) as a solid, liquid, or gas is made of two atoms of hydrogen (H) and one atom of oxygen (O). ~ Sodium chloride (NaCl), or table salt, is composed of one atom of sodium (Na) and one atom of chlorine (Cl). ~ Calcium carbonate (CaCO3), or chalk, is a compound of calcium (Ca), carbon (C), and oxygen (O). It is found in seashells. ~ Ammonia (NH3) is the active ingredient in window cleaners and fertilizers, and is made of one nitrogen (N) and three hydrogen (H) atoms. ~ Sucrose (C12H22O11), a sugar, is a white solid naturally produced by plants and algae and is made of 12 carbon atoms (C), 22 hydrogen atoms (H), and 11 oxygen atoms (O).

you to tell the difference between various types of matter

to tell the difference between various types of matter

1. Can the material be separated into parts by physical means, such as evaporating, freezing, or filtering? ~ Yes: It is a mixture. (Note: Some mixtures are hard to separate.) ~ No: It is a pure substance (go to Question 2). 2. Can the material be separated into parts by chemical means? ~ Yes: It is a compound. ~ No: It is an element.

separated into its components

complex chains of hydrogen, carbon , oxygen

chemical process that breaks down sugar into carbon and water vapor

chemical symbols

represent the elements

one - or two - letter symbols for elements

chemical formulas

represented by combinations of symbols in a chemical formula

chemical symbols show the elements that are combined together in the compound. In sulfuric acid, hydrogen (H), sulfur (S), and oxygen (O) are bound together

subscripts show the number of atoms of each element that are present in the compound. If there is no subscript, then only one atom of that element is present. In sulfuric acid there are 2 hydrogen atoms, 1 sulfur atom, and 4 oxygen atoms combined together. So in a sulfuric acid molecule there are 7 atoms

coefficients show the number of molecules that you have; this will be important when you learn about chemical equations

physical blend of two or more substances

mixture

element

sodium citrate is a compound with a total of 21 atoms