| A | B |
|---|
| Matter that has a uniform and unchanging composition like table salt and water | substance |
| a characteristic that can be observed or measured without changing the sample's composition like shape, color or weight | physical properties |
| physical properties that are dependent upon the amount of substance there is like mass, length, and volume | extensive properties |
| physical properties that are independent of the amount of substance that is present like density | intensive properties |
| the ability of a substance to combine with or change into one or moer substances like the ability of iron to form rust when combined with air | chemical property |
| Why is it important to state the specific conditions in which observations are made? | Both physical and chemical properties depend on temperature and pressure |
| A form of matter that has its own definite shape and volume like wood, iron, paper, and sugar. The particles of matter in a solid are very tightly packed but when heated, the solid expands but only slightly. | solids |
| A form of matter that flows, has constant volume, and takes the shape of its container like water, blood, and mercury. The particles are not rigidly held in place and move past each other. | liquid |
| A form of matter that flows to conform to the shape of its container and fills the entire volume of its container like neon, methane, and air. Because of the amount of space between the particles, this form of matter is easily compressed. | gas |
| the gaseous state of a substance that is a solid or liquid at room temperature like steam. | vapor |
| changes which alter a substance without chaning its composition like cumpling foil into a ball or cutting a sheet of paper and breaking a crystal and the different phase changes (melting and boiling point) of water | physical changes |
| A process that involves one or more substances changing into new substances and commonly referred to as a chemical reaction. Example: fermentation of grapes into wine, the rusting of iron. | chemical change |
| What are the starting substance called in a chemical reaction? (iron and oxygen) | reactants |
| What are the new substrances called in chemical reactions? (rust) | product |
| states that matter is neither created nor destroyed during a chemical reaction--it is conserved | Law of conservation of masses |
| a combination of two or more pure substances in which each pure substance retains its individual chemical properties like sand and water and table salt and water. | mixtures |
| a type of mixture where two substances do not blend smoothly throughout and in which the individual substances remain distinct like sand and water | heterogenous mixture |
| a type of mixture that has constant composition throughout like saltwater | homogenous mixture |
| Another name for homogeneous mixtures such as cough medicine and lemonade | solutions |
| A homogeneous mixture of metals, or a mixture of a metal and a nonmetal in which the metal substance is the major component like the dollar coin | alloy |
| Why are alloys used in spacecraft and automobiles? | manufacturers combine the properties of various metals in an alloy to achieve greater strength and durability of their products |
| A technique that uses a porous barrier to separate a solid from a liquid | Filtration |
| A separation technique that is based on the differences in the boiling points of the substances involved | distillation |
| A separation technique that results in the formation of pure solid particles of a substance from a solution containing the dissolved substance like rock candy | cystallization |
| A technique that separates the components of a mixture (called the mobile phase) on the basis of the tendency of each to be drawn across the surface of another material (stationary phase) like ink spread through paper | chromatography |
| A pure substance that can not be separated into simpler substances by physical or chemical means like copper, oxygen, and gold | elements |
| How many elements occur naturally on earth? | 91 |
| Consists of one, two, or three letters and the first letter is always capitalized | chemical symbols |
| Which element makes up approximately 75% of the mass of the universe? | hydrogen |
| What two elements make up 75% of the mass of the earth's crust? | oxygen and silicon |
| What three elements account for more than 90% of the human body? | oxygen, carbon, and hydrogen |
| Who developed the first version of the periodic table of elements? | Dmitri Mendeleev |
| What are the horizontal rows called in the periodic table? | periods |
| What are the vertical columns called in a periodic table? | groups or families |
| What do elements in the same group have in common? | similar chemical and physical properties |
| A combination of two or more different elements that are combined chemically like water, table salt, table sugar, and aspirin | compounds |
| What is a major difference between compounds and elements? | compounds can be broken down into simpler substances by chemical means such as heat or electricity |
| This states that regardless of the mass, a compound is always comprised of the same elements in the same proportion by mass | law of definite proportions |
| states that when different compounds are formed by a combination of the same elements, different masses of one element combine with the same relative mass of the other element in a ratio of small whole numbers like water H2O and hydrogen peroxide H2O2 | law of multiple proportions |
| When we compare the mass of oxygen in hydrogen peroxide to the mass of oxygen in water, what do we get? | 2:1 |
