Unit 1.5 flashcards (Sig figs, Chemical Vs. Physical, and E/C/M.)

High Accuracy

Very correct answers

Low Accuracy

Very wrong answers

High precision

Very similar answers

Low Precision

Very different answers

significant Figures

digits within a number that help determine how accurate a data value or measurement is.

Rules for significant digits

-All numbers that are not zero -Zeros in the middle of non-zero numbers -Zeros after the decimal -Zeros and coefficients in scientific notations

Rules for non-significant digits

-Leading or beginning zeros -Zeros in a larger number without a decimal

Look for least amount of decimals

When adding and subtracting

Look for least amount of sig figs

When multiplying and dividing

Physical Change

Does not alter the substance (Changes appearance)

Chemical Change

You can never go back to the original substance.

Physical properties

-Freezing and Boiling points (Phases changes) -Densities -Appearance -Ductile / Malleability -Brittle

Ductile

Can be pulled into wire

Malleability

Can be flattened into sheets

chemical properties

-Will it burn? -What other elements or compounds does it combine with to make compounds? -Will it dissolve in water? (Maybe Acid?)

Elements

Have certain physical and chemical properties that make them what they are. Can also be identified by those properties. (Can be found on the periodic table)

identifiers of elements

Density (Physical), and number of protons/ Atomic number (Chemical)

Compounds

Two or more elements that have been chemically combined. Done through bonding

Examples of compounds

H20 (water), CO2 (Carbon Dioxide), CO (Carbon monoxide)

Mixtures

Any of the substances before that have been physically combined.

Homogenous mixtures

Uniform, same layer

Heterogenous mixtures

Not uniform, separate layers.

Aqueous mixtures

mixtures with water

aq

dissolved in water