Chapter 1 Flashcards
What are the first 3 significant figures rules?
1) All non-zero digits are significant
2) Leading zeros are never significant
3)Zeros between non-zero digits are significant
What are the 2 rules regarding trailing zeros?
1) If there is a decimal point, the trailing zeros are significant
2)If there is no decimal point present, we assume that the trailing zeros are not significant.
What are the sig fig rules for Multiplication/Division?
We round off our answer so that it contains the same number of sig figs as our least accurate date (least amount of sig figs)
What are the sig fig rules for Addition/Subtraction?
We round off our answer to the least number of places after the decimal places from the original data.
Conversion from cm to inches
2.54 cm = 1 inch
Conversion from 1cm^3 to mL to cubic centimeter (cc)
1 cm^3 = 1 mL = 1 cc
Define Density
The mass (weight) per unit volume.
What is the equation for Density?
D= m/V
What is the density of water?
1.0 g/cm^3 = 1.00g/mL
What is Specific Gravity?
The comparison of the density of a substance with the density of water at the same temperature.
Define Chemistry
The study of the composition of matter and the changes it undergoes.
Define Matter
Matter is anything that has a mass and occupies space, so chemistry is a very broad subject.
Define Observations
Observations are things you observe and believe to be true. These things could be by chance or deliberate. Observations are a large part of experiments.
Define Hypothesis
An educated guess about why something happened. It is used to design experiments, which lead to new observations, which lead to new hypotheses.
Define Theory
An explanation of some event or phenomenon that has gained wide acceptance. Theories are generally developed only after extensive research and/or experimentation has been completed based on a set of hypotheses and observations. Theories are often later “proved” to be incorrect.
Define Laws
Laws are generally more specific than theories and also tend to include a mathematical relationship of some sort.
Define Element
A pure substance that cannot be broken down chemically
Define Compound
A pure substance consisting of at least 2 elements chemically combined
Define Mixtures
Physical combinations of elements and/or compounds
Heterogeneous mixtures
Components that are unevenly mixed
Homogeneous mixtures
Evenly mixed, divided down to individual atoms or molecules (Homogeneous mixtures are the same as solutions)
Define Precision
How close the results are to each other (high precision = high reproducibility)
Define Accuracy
How close the results are to the “true” (or accepted) value
