Vocabulary
Observation - is information collected through the five senses.
Inference - an interpretation or explanation of an observation.
Physical change - occur when objects undergo a change that does not change their chemical nature. Involves a change in physical properties
Examples of physical properties include: texture, shape, size, color, odor, volume, mass, weight, and density
Chemical Change - substances are changed chemically and display different chemical properties after the change. * A chemical change is irreversible.
Law of Conservation of Mass - In a chemical reaction, the mass of the products equals the mass of the reactants. (what you start with is what you will end with).
Reactants - the starting substances in a chemical reaction
Products - the substances that are formed after a reaction.
Accuracy - The measure of how close a measurement comes to the actual or true value of whatever is measured.
Precision - The measure of how close a series of measurements are to one another.
Matter – anything that takes up space and has mass.
Standard temperature and pressure = 0° Celsius at 1 atmosphere of pressure.
Atmosphere is a unit for measuring pressure
Avogadro’s number = 6.02 x 1023 volume of 1 mol of any gas at STP = 22.4 L
Ion- atoms or groups of atoms that have a positive or negative charge
Anion- negatively charged ion
Cation- positively charged ion
Molecules- small, electrically neutral “units”; maintain the properties of that substance
Formula unit- the lowest whole number ratio of ions in an ionic compound
Products are on the right side of the yield sign
Reactants are on the left side of the yield sign
Coefficients are the whole numbers that we place in front of a substance to balance an equation.
We correctly write the Nobel gases (such as oxygen and chlorine) with a 2 subscript (Cl2 02)
A precipitate is a solid that forms during a double