Matter and Measurement

Classification HeterogeneousMixtureCompound MatterElement Pure Substance Homogeneous

Chemistry Study of composition, structure, and properties of matter and of changes that occur in matter What is matter?  Anything that has _______ and takes up space What is mass?  Measure of the amount of _______ in a sample  This is different than weight.  Weight includes mass and the force of gravity on that mass

Matter Matter is composed of  Pure substances  Mixtures Pure substance All the particles are the same and they cannot be broken down by _________ processes Mixture Has more than one ____________ in it and the particles can be separated by _________ means

Atoms An atom is the smallest unit of an ________. An atom is the smallest unit of an ________.

Elements An element is composed of atoms that all have the same number of ______. An element is composed of atoms that all have the same number of ______. Elements are pure substances. Elements are pure substances.

Elements In pictures we represent different elements as different shapes or sizes or colors. In pictures we represent different elements as different shapes or sizes or colors.

Chemical symbols Elements have been given symbols to represent them in shorthand. Some symbols are shortened forms of the element name:  Carbon – COxygen – ONeon – Ne Some symbols come from names in languages other than English.  Sodium – NaCopper – Cu Symbols are always 1-2 letters, capital first, then small

Elements Listed in the periodic table Must know  1-31, 33-38, 40, 42, 46-48, 50-51, 53-57, 74, 78-80, 82-83, 86-87, 89, 92, and 94

Compounds A compound is composed of several types of elements bonded together. A compound is composed of several types of elements bonded together. Compounds are pure substances. Compounds are pure substances.

Molecules A molecule is the smallest unit of a _________. A molecule is the smallest unit of a _________.

Composition The composition of a sample tells  what elements are in the sample  The simplest ratio of those elements with respect to each other.

Chemical formulas A chemical formula tells which elements are in a compound, and the simplest ratios of the elements. A subscript is used after an element if there is more than one atom of that type in a molecule.  H 2 O = 2 hydrogen atoms with 1 oxygen atom.  Al 2 O 3 = 2 aluminum atoms with 3 oxygen atoms.

Mixtures Substance containing 2 or more pure substances mixed together Classified as heterogeneous or homogeneous

Heterogeneous Mixture Contains phases Interface- area between two phases

Homogeneous Mixture Same appearance throughout Classified as ___________

Suspensions, Colloids, and Solutions Heterogeneous mixture  Suspension  _______ particle size  Particles suspended for a time but will settle out  Colloid  _______ particle size  Particles stay suspended Homogeneous mixture  Solution  _______ particles size  Particles stay suspended

Solution _______- thing being dissolved _______- thing doing dissolving

Physical vs Chemical Properties- description of matter  Physical- characteristic of matter displayed without a chemical change  Odor, color, density, etc…  Chemical-characteristic of matter displayed during a chemical change  Reactivity Changes- description of a change to matter  Physical- change in matter that does not affect its composition  Phase change, dissolving, cutting or tearing, etc…..  Chemical- change in matter that does affect its composition  Chemical rxn

Property Types Extensive  Property that is dependent on the amount of matter present in a sample  For example: _______________________ Intensive  Property that is not dependent on the amount of matter present in a sample  For example: ________________________

Measuring Matter Two Methods  Qualitative- gives a ________________  For example: Sodium chloride is a white, crystalline structure.  Quantitative- gives a _______________  For example: Mass = 13.5 g

Measurement Tools Length  ______________ Mass  ___________ Time  _____________ Temperature  ______________ Volume  ____________________

Precision and Accuracy Precision deals with how consistent a measurement is Accuracy deals with correct a measurement is

Significant Figures Rules apply only to _______________  Degree of uncertainty Do not apply to  Counted objects  For example- 6 sides in a hexagon or 20 books  Defined fractions and values  For example- radius is half of a diameter of a circle or 1000m is 1km

Determining Number of Sig Figs All _________ digits are significant Zeros  Significant if  Caught between two significant figures (107)  Found at the end of a number to the right of the decimal point (2.00)  Not significant if  Found to right of non-zero digits in a number without a decimal point (50)  Found to the left of the decimal point in a number less than 1 (0.5)  Found to the right of the decimal point in front of the non-zero digits (0.005)

Sig Figs in Calculations Addition and Subtraction  Answer should have the same number of places after the decimal as the number with the least number of places after the decimal that is used in the problem  It is best to round after completing the calculation Multiplication and Division  Answer should have the same number of sig figs as the number with the least number of sig figs used in the problem  It is best to round after completing the calculation

SI Units Modern version of metric system SI Base Units  Length- __________  Mass- ___________  Time- ___________  Temperature- _________  although we will often use Celsius ( ◦ C)  K = °C Derived Unit  Combine multiple base units  For Example: _____________

Metric System Prefixes Tera (T)10 12 Giga (G) 10 9 Mega (M)10 6 Kilo (k)10 3 Hecto (h)10 2 Deca (da or dk)10 1 Deci (d)10 -1 Centi (c) Milli (m)10 -3 Micro (µ)10 -6 Nano (n)10 -9 Pico (p)10 -12

Scientific Notation Method of expressing very large or small numbers Steps 1. Decimal is placed in the number so that that number is greater than or equal to 1 but less than 10 (for example: becomes ) 2. Notation is added to reflect the number of places that the decimal moved and the direction that it moved in  If decimal is moved 4 places to the left, a “x 10 4 ” will be added to the number  If decimal is moved 4 places to the right, a “x ” will be added to the number

Factor Labeling Method used to convert numbers from one unit to another Multiply (and divide) using conversion factors  Factors need to equal 1 when divided 2.54 cm ––––––– = 1 1 in. ––––––– = cm