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Chemistry

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Chemistry 1001 Exam 1 Review

True/False Questions

1) The mass of an object, 0.000455 g, expressed in scientific notation is 4.55x10^-3 g. -FALSE

2) Exact numbers have an unlimited number of significant figures. -TRUE

3) If you know the density of a liquid and its volume, the mass of the liquied may be calculated using the equation: m=V/d. -FALSE

4) Both carbon dioxide molecules and water molecules consist of three atoms bonded together with atoms arranged as in a triangle. -FALSE ( haven’t covered this in class)

5) Saltwater is a homogeneous mixture that can be boiled at a fixed temperature. -FALSE (didn’t cover in class) first part is true

6) In physical changes, the atoms or molecules that compose the matter do not change their identity, even though the matter may change its appearance. -TRUE

Multiple Choice
7) Which of the statements below is NOT ALWAYS part of the scientific method? –Using scientific notation
-observation and measurement
- formation of hypothesis
-testing of a hypothesis by experiment
-refinement of hypotheses is needed

8) Which of the following is an example of a scientific theory? a. All matter is composed of small, indestructible particles called atoms. b. In a chemical reaction, matter is neither created nor destroyed. c. When a can of soda pop is opened, a fizzing sound is heard. d. Flammable objects contain phlogiston.

e. None of the above.

9) A sample of wood with a mass of 4.0 grams was burned in an open dish. The ashes weighed 2.2 grams. What happened to the rest of the wood? -The remaining 1.8 grams was converted into gaseous compounds.

10) The correct scientific notation for the number 500.0 is: -5.000x10^2

11) The correct decimal representation of 1.201x10^-7 is: f. 12010000
g. 0.0001201
h. 0.0000001201
i. 1201.000
j. none of the above

12) There are exactly 2.54 centimeters in 1 inch....