Chapter 1 - Study of Chemistry Flashcards
(24 cards)
Physical Change
Substance alters its physical properties, not its composition; does not change the identify of the substance Physical change can generally be reversed by heating or cooling
Chemical Change
A substance is converted into a different substance Chemical change cannot be reversed by heating/cooling
Scientific Method
Process involving creative proposition and tests aimed at objective, verifiable discoveries
Observation
Facts that our ideas must explain
Hypothesis
Proposal made to explain an observation
Experiment
Set of procedural steps that tests a hypothesis
Controlled Experiment
An experiment that measures the effect of one variable on another while keeping all other variables constant
Model
Simplified, not an exact, representation of some aspect of nature that we use to predict related phenomena
Mega (M)
1 x 106
Kilo (K)
1 x 103
Deci
1 x 10-1
0.1
Centi
1 x 10-2
0.01
Milli
1 x 10-3
0.001
Micro
1 x 10-6
Nano
1 x 10-9
Pico
1 x 10-12
Density
Mass/Volume
Kelvin
T(K) = T(C) + 273.15
T(C) = T(K) - 273.15
Adding/Subtracting Significant Figures
Final answer is rounded to the number with the least decimal places
Multiplying/Dividing Significant Figures
Final answer is rounded to the number with the least significant figures
Precision
Reproducibility; how close the measurements are in a series are to each other
Accuracy
How close each measurement is to the actual value
Systematic Error
Values that are either all higher or all lower than the actual value; often caused by a faulty device
Random Error
Values that are higher and lower than the actual value; depends on the measurer’s skill and the instrument’s precision
