1. Measurements
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2. Measurement in Chemistry
In chemistry we
do experiments
measure quantities
use numbers to report measurements

3. Metric System (SI) Is a decimal system based on 10
Used in most of the world
Used by scientists and hospitals
* SI means System International

4. Units in the Metric System
length meter m
volume liter L
mass gram g
temperature Celsius °C

5. Metric Prefixes Prefix Symbol Factor Number Factor Word Kilo- k 1000
Metric Units
The metric system has prefix modifiers that are multiples of 10.
Prefix
Symbol
Factor Number
Factor Word
Kilo- k
1000
Thousand
Hecto- h
100
Hundred
Deca-
da or dk 10
Ten
Unit
m, l, or g 1
One
Deci- d .1
Tenth
Centi- c
.01
Hundredth
Milli- m
.001
thousandth

6. Place Values of Metric Prefixes
Thousand
Hundred
Ten
One
Tenth
Hundredth
Thousandth km kg kL hm hg hL
dkm
dkg
dkL m g L dm dg dL cm cg cL mm mg mL

7. In every measurement there is a Number followed by a
Stating a Measurement
In every measurement there is a
Number followed by a
Unit from a measuring device
The number should also be as precise as the measurement!

8. Uncertainty in Measurement
Scientific measurements are reported so that every digit is certain except the last, which is estimated.

9. Some Tools for Measurement
Which tool(s) would you use to measure:
A. temperature
B. volume
C. time
D. mass

10. Intensive vs. Extensive Properties
Intensive—independent of the amount of substance
They do not depend on the amount of matter
Color, Odor, Luster, Malleability, Conductivity, Hardness, Melting/ Freezing Point, Boling Point, and Density
Extensive—dependent upon the amount of substance
They depend on the amount of matter present
Mass, Weight, Volume, and Length

11. When we measure length we measure how long something is.
You can measure the length of ANYTHING!

12. Standard units Millimeters (mm) Centimeters (cm) Meters (m)
Kilometers (km)

13. Mass vs. Weight
Mass: Amount of Matter (grams, measured with a BALANCE)
Weight: Force exerted by the mass, only present with gravity (pounds, measured with a SCALE)
Can you hear me now?

14. Tools for measuring Mass
The triple beam balance

15. How to use a triple beam balance
1) Make sure that the balance scale is at zero.
2) Place object on balance scale the larges and move the largest rider one notch at a time until the beam drops. Move the rider back one notch (make sure it lock in place)
3) Move the next largest rider until the beam drops. Back it up one notch.
4) Move the smallest rider until the beam swings equally above and below the zero mark.
5) Add up all the numbers to find the mass!

16. Volume is the measure of the Space something takes up.
What is Volume?
Volume is the measure of the Space something takes up.
It is the measure of how much a container of a particular shape will hold - liquids, dry substances, etc.

17. The formula for finding the volume of a rectangle is ….
What’s the formula?
The formula for finding the volume of a rectangle is ….
L x W x H = Volume
This means we take the length times the width, then multiply that by the height.

18. Measuring Volume
We will be using graduated cylinders to find the volume of liquids and other objects.
Read the measurement based on the bottom of the meniscus or curve. When using a real cylinder, make sure you are eye-level with the level of the water.
What is the volume of water in the cylinder? _____mL
What causes the meniscus?
A concave meniscus occurs when the molecules of the liquid attract those of the container. The glass attracts the water on the sides.
Top Image: Bottom Image:

19. Measuring Liquid Volume
What is the volume of water in each cylinder?
Images created at A B C
Pay attention to the scales for each cylinder.

20. Volume Displacement 25 mL A solid displaces a matching volume of water
when the solid is placed in water.

21. Measuring Solid Volume
10 cm
9 cm
8 cm
We can measure the volume of regular object using the formula length x width x height.
_____ X _____ X _____ = _____
We can measure the volume of irregular object using water displacement.
Amount of H2O with object = ______ About of H2O without object = ______ Difference = Volume = ______
Click here for an online activity about volume. Choose Lessons  Volume & Displacement

22. Density
Density is defined as mass per unit volume. It is a measure of how tightly packed and how heavy the molecules are in an object. Density is the amount of matter within a certain volume.
Density is the amount of matter within a certain volume.

23. Which one is more dense? Demonstration: People in a square
How about this: Which square is more dense?

24. Which one is more dense?

25. water and ice have different densities Which one is more dense?

26. To find the density 1- Find the mass of the object
2- Find the volume of the object
3- Divide
Density = Mass g
Volume c³
ALWAYS REMEMBER UNITS!

27. DENSITY - an important and useful physical property
Aluminum
Platinum
Mercury
13.6 g/cm3
21.5 g/cm3
2.7 g/cm3

28. DENSITY Density is an INTENSIVE property of matter. Styrofoam Brick
does NOT depend on quantity of matter.
temperature
Contrast with EXTENSIVE
depends on quantity of matter.
mass and volume.
Styrofoam
Brick

29. Problem A piece of copper has a mass of 57. 54 g. It is 9
Problem A piece of copper has a mass of g. It is 9.36 cm long, 7.23 cm wide, and 0.95 mm thick. Calculate density (g/cm3).

30. If you have 2 or more substances,
the MORE dense substance will be on bottom
The LESS dense substance will be on top

31. Temperature Particles are always moving.
When you heat water, the water molecules move faster.
When molecules move faster, the substance gets hotter.
When a substance gets hotter, its temperature goes up.
LecturePLUS Timberlake

32. Temperature is measured in degrees.

33. Temperature is measured on two scales: Celsius and Fahrenheit.37 C
98.6 F

34. The lower case “C” is the symbol for the Celsius scale.
We will use Celsius C
The lower case “C” is the symbol for the Celsius scale.