Unit 1.5- Sig figs, Chemical Vs. Physical, and E/C/M.
DO NOT CLICK FLASHCARDS FROM HERE (OR STUDY). Click here
Significant figures:
are digits within a number that help determine how accurate a data value or measurement is.
Accuracy Vs. Precision:
High Accuracy and High Precision- Multiple correct answers.
Low Accuracy and High Precision- Multiple incorrect answers (similar answers).
High Accuracy and Low Precision- Varied correct answers.
Low Accuracy and Low Precision- Varied incorrect answers.
Rules for sig figs:
All numbers that are not zero are significant
Zeros in the middle of non-zero numbers are significant
Zeros after the decimal are significant
Zeros and coefficients in scientific notations are significant
Leading or beginning zeros are NOT significant
Zeros in a larger number without a decimal are NOT significant
Math rules for sig figs:
When adding or subtracting round/look for the least amount of decimal places.
When multiplying and dividing look for the least amount of sig figs.
Examples for Sig Figs:
Normal examples:
2.2 cm = 2 sig figs
2.22cm = 3 sig figs
100.3cm= 4 sig figs
25.2 mL= 3 sig figs
1002= 4 sig figs
Weird examples:
1000 cm= 1 sig fig
1000,= 4 sig figs (, = decimal)
Physical Vs. Chemical:
Physical Change: Does not alter the substance (Changes appearance)
Chemical change: You can never go back to the original substance.
Physical properties (Changes):
Freezing and Boiling points (Phases changes)
Densities
Appearance
Ductile (Can be pulled into wire)/ Malleability (Can be flattened into sheets)
Brittle
Chemical properties (Changes):
Will it burn?
What other elements or compounds does it combine with to make compounds?
Will it dissolve in water? (Maybe Acid?)
Determined by the makeup (Protons/ electrons) of the substance.
Elements/ Compounds/ Mixtures:
Elements:
Have certain physical and chemical properties that make them what they are
They can be identified by those properties.
Density (Physical)
number of protons/ Atomic number (Chemical)
Compounds:
Two or more elements that have been chemically combined
Done through bonding
Examples:
H20 (water), CO2 (Carbon Dioxide), CO (Carbon monoxide)
Can be separated by chemical reactions.
Mixtures:
Any of the substances before that have been physically combined.
Homogenous- Uniform, same layer (Homo= Same)
Heterogenous- Not uniform, seperate layers (Hetero = different)
Aqueous mixtures (Aqueous meaning water)
aq= dissolved in water
Next Unit: Unit 2- Atoms
Unit 1.5- Sig figs, Chemical Vs. Physical, and E/C/M.
DO NOT CLICK FLASHCARDS FROM HERE (OR STUDY). Click here
Significant figures:
are digits within a number that help determine how accurate a data value or measurement is.
Accuracy Vs. Precision:
High Accuracy and High Precision- Multiple correct answers.
Low Accuracy and High Precision- Multiple incorrect answers (similar answers).
High Accuracy and Low Precision- Varied correct answers.
Low Accuracy and Low Precision- Varied incorrect answers.
Rules for sig figs:
All numbers that are not zero are significant
Zeros in the middle of non-zero numbers are significant
Zeros after the decimal are significant
Zeros and coefficients in scientific notations are significant
Leading or beginning zeros are NOT significant
Zeros in a larger number without a decimal are NOT significant
Math rules for sig figs:
When adding or subtracting round/look for the least amount of decimal places.
When multiplying and dividing look for the least amount of sig figs.
Examples for Sig Figs:
Normal examples:
2.2 cm = 2 sig figs
2.22cm = 3 sig figs
100.3cm= 4 sig figs
25.2 mL= 3 sig figs
1002= 4 sig figs
Weird examples:
1000 cm= 1 sig fig
1000,= 4 sig figs (, = decimal)
Physical Vs. Chemical:
Physical Change: Does not alter the substance (Changes appearance)
Chemical change: You can never go back to the original substance.
Physical properties (Changes):
Freezing and Boiling points (Phases changes)
Densities
Appearance
Ductile (Can be pulled into wire)/ Malleability (Can be flattened into sheets)
Brittle
Chemical properties (Changes):
Will it burn?
What other elements or compounds does it combine with to make compounds?
Will it dissolve in water? (Maybe Acid?)
Determined by the makeup (Protons/ electrons) of the substance.
Elements/ Compounds/ Mixtures:
Elements:
Have certain physical and chemical properties that make them what they are
They can be identified by those properties.
Density (Physical)
number of protons/ Atomic number (Chemical)
Compounds:
Two or more elements that have been chemically combined
Done through bonding
Examples:
H20 (water), CO2 (Carbon Dioxide), CO (Carbon monoxide)
Can be separated by chemical reactions.
Mixtures:
Any of the substances before that have been physically combined.
Homogenous- Uniform, same layer (Homo= Same)
Heterogenous- Not uniform, seperate layers (Hetero = different)
Aqueous mixtures (Aqueous meaning water)
aq= dissolved in water