Study guide answer key

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INTRO. UNIT STUDY GUIDE- test 11/13/15
For the test, you should be able to: (Check off each item you have mastered.)
 Demonstrate knowledge of safe laboratory rules and procedures.
 Demonstrate how to use various instruments to make accurate measurements.
 Apply correct units to all measurements.
 Calculate the volume of a regular solid.
 Calculate the volume of an irregular object, using water displacement.
 Calculate density, given an object’s mass and volume.
 Manipulate the density formula
 Know the density of water and why objects float or sink when placed in water.
 Be able to state a problem, a hypothesis and steps of the scientific method.
 Explain the difference between an independent and dependent variable and be able to identify them.
 Determine the constants in an experiment.
 Identify the elements of a good graph.
 Be able to make a conclusion after analyzing data.
 Calculate protons, electrons and neutrons
 Identify the difference between physical and chemical properties and changes
For the ice/salt water lab:
1. What was the independent variable? Amount of Salt, the cause of the experiment, changed on
purpose.
2. What was the dependent variable?
the outcome of the lab.
3. What was the control?
variable too.
Melt time, The effect of the experiment, measurement for
Fresh water, The factor that we compare the independent
WORD BANK:
balance
chemicals
chemical
constants
fire
glass
graduated cylinder
hypothesis
inference
one
physical
problem
qualitative
quantitative
4. To state the __ problem is to ask a question.
5. A __ hypothesis __ is a testable statement.
6. __ constants
_______ are all the things that need to stay the same
during the experiment.
7. In an experiment, you can only have ____ one _____ variable.
8. A _ qualitative _______ observation is one you make with your 5 senses.
9. Measurements taken in lab are an example of _ quantitative _____ observations.
10. An __ inference _____ is an interpretation based on your knowledge
and observations.
11. A ____ balance _____is used to measure mass.
12. A _ graduated cylinder ____ is used to measure volume.
13. Goggles are worn in the lab when working with __ chemicals _____,
______ fire _______________ and _______ glass ____________.
14. Burning paper is a _________ chemical ___ change.
15. Ice melting is a _____ physical ________ change.
Circle
C
the independent variable and Underline the dependent variable for #19.
19. The higher the hikers climb in altitude, the less oxygen there is to breathe.
IV: altitude
DV: amount of oxygen
20. What is the formula to calculate density? D = m/v
21. Using the following information, find the density: (show your work)
Mass: 30 g
Volume: 15 mL
D= m/v
30g/15mL = 2g/mL
22. If an object’s density is higher than water’s, it will
float
or
sink
in water.
23. If an object’s density is lower than water’s, it will
float
or
sink
in water.
24. What is the measurement for:
_________29mL_________ (don’t forget your units)
25. What is the measurement of the apple in:
_____________________________
(don’t forget your units) 10mL – 5mL = 5mL
26. What is the measurement for the key: ______3.3cm___________ (don’t forget your units)
27.
What
is
the
mass:
__________183.6g
(don’t
forget
your
units)
28. Convert the following measurements:
204.6 cm = 0.002046 km
58.26 dg = 5826 mg
6284.25 hL = 628425 L
29. Put the scientific method in the correct order (1-7):
__5___Collection of data
___1__Problem
__4___Procedure
__3___Materials ___2__Hypothesis __7___Conclusion
__6___Analysis
30. List 4 of lab safety rules and 4 unsafe safe behaviors.
31. Identify if the following is physical or chemical change. Then explain why.
Rust- Chemical change
Why? When something rusts, the metal that is rusting is changed into a different substance- iron turns into iron oxide.
Nail polish- Physical change
Why? The nail polish is unchanged, the water it was physically mixed with evaporated. It is just coating the surface, not
chemically bonding with it.
Tarnish- Chemical change
Why? Tarnish is a type of rust where oxygen chemically combines with silver, producing silver oxide
Flammability- Chemical change
Why? The material you start with, wood or paper, is changed into a new substance, ash.
Element Name
Element
symbol
Atomic #
Atomic
Mass
Number of
Protons
Number of
Neutrons
Number of Electrons
F
9
18
9
9
9
25
55
25
30
25
11
23
11
12
11
Fluorine
Manganese
Mn
Na
Sodium
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