Chemistry Study Guide: Test #1. A hypothesis is best described as: An educated guess If …….then…….. The scientific method is: A systematic approach to.
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A hypothesis is best described as:
An educated guess
If …….then……..
The scientific method is:
A systematic approach to answer a question - testable
A scientific theory is best described as:
An explanation supported by many experiments
The dependent variable is best described as:
The one that changes; located on the Y axis
In an experiment, the independent variable is the one that:
“I” can control; located on the X axis
The best way to find the volume of a marker is called:
Water displacement
The formula for density is:
D = m/v
In determining how many significant figures a number has, you must first look for a
decimal
If a decimal is present, then you start counting from the front (left)
If a decimal is absent, then you start counting from the back (right)
PacificAtlantic
The first rule of lab safety is: Tell the teacher
Volume is measured in mL or cm3, which are the same
Density is written in which units? g/mL or g/cm3
When measuring irregular objects (such as cylinders, marbles, rocks) you should use water displacement as the method of finding volume.
You can only use the L*W*H method of finding volume when objects are considered regular in shape or easily measured with a ruler.
Metric Measurements
Kilo Hecto Deca m deci centi milli 1000 100 10 L 10 100 1000
g
Kids have dropped over dead converting metric
Which prefix means 1,000? Kilo
Which prefix means 1/100? centi
Which prefix means 1/1000? milli
Read the following graduated cylinders. Make sure to include (mL) in your answer
52.9 mL
6.64 mL20.6 mL
Descriptor Qualitative or Quantitative
Red Qualitative
17 centimeters Quantitative
46 desks Quantitative
Rusty Qualitative
48 marbles Quantitative
152 milliliters Quantitative
Smelly Qualitative
Calculate the densities of the following objects. Remember to place units after each
number.
Object A:
Length = 6 cm
Width = 3 cm
Height = 1 cm
Mass = 36 g
Volume = 18 cm3
Density = 2 g/cm3
Object B:
Length = 10 cm
Width = 5 cm
Height = 2 cm
Mass = 300 g
Volume = 100 cm3
Density = 3 g/cm3
Object C:
Use the water displacement method to determine the density of Object C (silly putty)
Initial water level in graduated cylinder =
25 mL
Water level after placing silly putty into graduated cylinder = 29 mL
Mass of silly putty = 8g
Volume = 4 mL
Density = 2 /mL
Which of the following materials will float on water (density = 1.00 g/cm3)?
Corn oil = .93 g/cm3 -- float
Glycerine = 1.26 g/cm3 -- sink
Corn syrup = 1.38 g/cm3 -- sink
Wood = .85 g/cm3 -- float
Steel = 7.81 g/cm3 -- sink
Rubber = 1.34 g/cm3 -- sink
Ice = .92 g/cm3 -- float
Water = 1.00 g/cm3 -- neither
Complete the following calculationsbe sure to use the proper number of significant
figures
51.8 kg + 65.23 kg = 117 Kg
16 m x 31 m x 0.003 m = 1.488 1 m3
3.45 m ∕ 2.1 s = 1.6 m/s
45.21 x 3.0 = 136.63 140____
12.01 g - 6.0 g = 6.01 6.0 g
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