Metric – Science and Measurement

Applied Chemistry 4.0

I. Science

A branch of knowledge built over many years from scientists following a specific method.

A. Three Main Branches: 1. Life Science (Biology)2. Physical Science (Chemistry/Physics)3. Earth Science (Environmental)

B. Chemistry is the study of matter and its composition, structure, property, and changes.

1. Chemistry is a central science because it overlaps so many sciences.

2. Pure chemistry: used for research

3. Applied chemistry: used in ordinary people’s lives.

II. Scientific Method

A. Series of steps used to find a solution to a problem.

B. Steps1. Observe and consider a problem2. Form a hypothesis3. Design an experiment4. Perform an experiment5. Collect and Analyze Data6. Summarize the Results

Example: Milk Lab

Experimental Design

Observations: Things you experience through your senses or aided by technology.

1. Qualitative: descriptive - color, shape, size

2. Quantitative: can be measured (a number + unit)

Experimental Design (cont.)

Hypothesis: testable statement

Experiment: tests a hypothesis

Natural Law: describes how nature behaves

Theory: explains why nature behaves the way it does

Measurement & Calculations

International System of Measurement (SI) Modern Metric System

1. Based upon multiples of 10

2. 7 metric units are base units

Origin of the Metric System

During the18th century scientists measured the distance from the earth’s equator to the North Pole and divided it into ten million parts.

This number is equal to exactly 1 meter.

Metric Units

Mass gram gbalance

Length meter m ruler Volume liter L graduated

cylinder Time second s clock Temperature Kelvin K

Celsius °C thermometer

The Meter

The original standard for the meter was kept in a safe in France.

The meter stick is a replica of that standard.

A meter is made up of 100 centimeters and 1000 millimeters.

Lasers are now used to determine the standard for a meter.

The Gram

Mass is the amount of matter in an object.

1 cm3 of water = 1 gram.

The standard kilogram is kept under lock and key in Washington, DC and other cities around the world.

Metric Prefixes used before a unit to make it smaller or larger

Mega- M 1,000,000 Kilo- k 1000 Hecto- h 100 Deka- da 10 BASE UNIT ----- ----- Deci- d 0.1 Centi- c 0.01 Milli- m 0.001 Micro µ 0.000001 Nano n 0.000000001 Pico- p 0.000000000001

BASE UNIT

kg hg dag g dg cg mg

km hm dam m dm cm mm

kL hL daL L dL cL mL

1 mL = 1 cm3

Metric Conversions

How to use a ruler

3.97 cm

7.15 cm

How to use a graduated cylinder

Read the meniscus

How to use a graduated cylinder

36.4 mL 19.0 mL 6.25 mL

How to read a triple beam balance

Ohaus Triple Beam Balance Tutorial

Reading A Triple Beam Balance Tutorial

28.570 g

How to read a triple beam balance

Ohaus Triple Beam Balance Tutorial

Reading A Triple Beam Balance Tutorial

109.076 g

Equations Involving Metrics

Area = Length x Width = L x W– Unit: m2 or cm2

Volume = Length x Width x Height = L x W x H– SI unit: m3 or cm3 non-SI unit: L 1 cm3 = 1 mL

Density = Mass Volume

-unit: g/cm3 or g/mL

M

D V

Density Column

Density

Density of an Irregular solid:

1- Find the mass of the object

2- Find the volume if the

object by water displacement!

Density Problems

1. Calculate the density of a 12.55 g sample that has a volume of 4.65 mL.

D = mV

=12.55 g4.65 mL

= 2.70 g/mL

2. What is the mass of a 2.73-cm3 sample of silver with a density of 10.49 g/cm3?

m = D x V = 2.73 cm310.49 g/cm3 x

m = 28.64 g

Density Problems

3. A 39.46-g sample of silicon has a density of 2.34 g/cm3. Calculate the volume of this sample of silicon.

V = mD

= 39.46 g

2.34 g/cm3= 16.86 cm3

Density Problems

4. You were given the densities of 3 liquids below. Write the letter in the appropriate layer in the container below.

LiquidDensity (g/mL)

A 0.785

B 1.25

C 1.00 B

C

A

Important Temperatures

Note: Celsius is not the SI unit for temperature. However, it is most commonly used in laboratories. Kelvin is the SI unit for temperature.

To convert from Celsius to Kelvin add 273

• K = °C +273

Freezing Point 32°F 0°C 273K Boiling Point 212°F 100°C 373K Human Body Temp 98.6°F 37°C 310K Absolute Zero -459.7°F -273°C 0K

Temperature Scales