Chemistry Unit 1
While measuring the mass of a 5.0g weight, you observe measurements of 3.4g, 5.4g, and 7.3g. These measurements do not have good precision nor _____.
Accuracy
Scienetific Method
An organized approach to solve problems. Observation, Hypotheses, Experiment, Analysis, Conclusion/Theory
In the scientific method, _____ is the step in which experimental results are used to decide the validity of each hypothesis.
Analysis
In a compound the elements are _____ together, whereas in a mixture the substances are blended together.
Bonded
Physical Changes
Changes in appearance without change in composition
A _____ property of water is that it is unreactive with oil.
Chemical
Paper burning is an example of a _________________________ change.
Chemical
Scientific notation includes two parts, the _____ and the power of 10.
Coefficient
Law of Conservation of Mass
In a chemical change or physical change, matter cannot be created or destroyed
In the gas state, a substance will have a(n) _____ volume.
Indefinite
Density is a __________________________ property of a substance
Physical
Phase changes are classified as _____ changes.
Physical
How close multiple measurements are to each other is called _____.
Precision
______________________________ always have uniform and definite compositions.
Pure Substances
While observing a chemical reaction, you say to your lab partner "the outside of the beaker is very hot." This is an example of a _____ observation.
Qualitative
The measurement of 13.5° Celsius from a thermometer is a _____ observation.
Quantitative
Multiplication and Division with sig figs
The answer is rounded to the same number of the sig figs as the number used in the calculation with the least significant figures. (Look at the total number of sig figs) ex. 17.85 / 2.13 = 8.38028= 8.38
Quantitative
observation made with a measuring instrument and includes both a number and a unit Ex. ruler, balance, theremometer
Chemical Changes
one or more substances react to form new substances with different chemical and physical properties
physical properties
properties that can be measured or observed without changing the identity (or composition) or a substance
chemical properties
properties that indicate how a substance reacts with other substances
When measuring off any instrument, you must measure all certain digits off the instrument plus one extra _____ digit.
Estimated
____ is an example of a physical change.
Freezing
homogeneous mixture
Has a uniform composition
An exact number has an _____ amount of significant figures.
Infinite
__________________________ zeros are never significant
Leading
In the _____ state, substances have a definite volume and an indefinite shape.
Liquid
__________________________ is a measure of the amount of matter in an object.
Mass
Anything that has mass or volume is called _____.
Matter
Chemistry the study of _________________________ and the changes it undergoes.
Matter
Rules for Significant Figures
Non-zero digits are always significant. Captive zeros are always significant. Trailing zeros are only significant if the number contains a decimal.
The _______________________ is the step in the scientific method in which you use your 5 senses in order to define the problem.
Observation
Law
Used to describe a natural phenomenon which has been tested over a long period of time under different conditions
two parts of scientific notation
coefficient and power of 10
Qualitative
descriptive ex. hot, cold, weight, blue
Heterogeneous mixtures
does not have a uniform composition ex. Cereal, Pizza, Salad
Pure substances
have uniform and definite composition
Accuracy
how close a measurement is to the true value or accepted value aCCurate=Correct
Precision
how close multiple measurements are to each other pRecision= Reproductibility
In a chemical equation the reactants are always written on the _________________ side of the arrow.
left
Addiction and subtraction with sig figs
the answer is rounded to the same number of decimal places or as the number used in the calculation with the LEAST decimal places. (Look at the decimal places) ex. 5.7 + 2.11 = 7.81 = 7.8
Mixtures
two or more substances that have been physically mixed together
There is ________ in all measurements
uncertainty