Unit2_Notes.pptx

(1)

UNITS AND

(2)

Warm Up 9/24:

(3)

Warm Up 9/24:

•

What is smaller, a cell or an

atom?

(4)

Think of different types of

matter…

•

In biology you learned that

organisms are made up of

cells

•

Are cells a form of matter?

•YES!! (they have a mass and take

up space)

•cells are made up of different

(5)

How many cells do you think

make up the average human

body?

37 MILL

ION?

37 BIL

LIO

(6)

Let’s think about cells again…

•You learned that a cell is the basic building block

of all living organisms  Well an atom is the basic building block of ALL MATTER (including cells,

water, rocks, etc)

•In each cell there are approximately 100 trillion

(100,000,000,000,000) atoms!

•It is estimated that there are on

average 37 trillion cells in the human body.

•That is 37,000,000,000,000,

(7)

Expressing numbers in

chemistry

•_{In chemistry, we often work with}

very

large

and very small numbers.

•Scientific notation is a way to express both

(8)

SCIENTIFIC NOTATION: proper

form

•Basic form: M x 10 +/- n

•1 ≤ M < 10

•1,2,3,4,5,6,7,8,9… (doesn’t have to be a

whole #)

•There should only be ONE DIGIT to the left

of your decimal (ex 5.1, 2.6)

•n (the exponent) is the number of times the

decimal needs to be moved

•The + or – sign represent the direction the

(9)

Exponents….

•

M x 10

+/- n

•Negative exponent: decimal is moved

to the LEFT

•represents numbers smaller than 1

•Positive exponent: decimal is moved

to the RIGHT

(10)

Examples: Putting numbers into Scientific

Notation

•

Large numbers :

•

37,000,000,000,000 cells



3.7x10

13

cells

•

100,000,000,000,000 atoms



1.0x10

14

atoms

•

Small numbers

(11)

Putting Numbers into Scientific Notation Practice…

•0.00000672

•12,600,000,000 •100,000

(12)

Taking Numbers out of Scientific Notation Practice…

•8.0 x 104 •3.5 x 10-2 •2.65 x 103

Remember…

A positive exponent means it’s greater than

1!!!

A negative exponent means it’s less than

(13)

(14)

Scientific notation: ADDITION AND

SUBTRACTION

•In order to add/subtract numbers that are in

scientific notation their exponents must be the same!

•Ex)

• 5.0+3.2 = 8.2

•Rules for ADDING

•Check that the exponents of both numbers are the

same

•ADD the digits

•The exponent stays the same

(15)

Scientific notation: ADDITION AND

SUBTRACTION

•In order to add/subtract numbers that are in

scientific notation their exponents must be the same!

•Ex)

• 5.0-3.2 = 1.8

•Rules for SUBTRACTING

•Check that the exponents of both numbers are the

same

•SUBTRACT the digits

•The exponent stays the same

(16)

What if they don’t have the same exponent?

8.5 x 10 3 kg + 3.2 x 10 4 kg

(17)

Warm up: 9/24

(18)

Intro Lab

•5 demos

•Bunsen Burner

•Pouring Liquids/Handling Chemicals •Measuring Volume

•Filtration

•Quick Lab

•Qualitative and Quantitative Observations of Physical and Chemical Changes

•Post lab: SKIP 5&6

(19)

Directly or Inversely Proportional

•Directly Proportional: y= kx

•Basically…. •_If x y

•_If x y

•Inversely Proportional: y= k/x_If

•Basically….

(20)

Warm up 9/28 ( YOU MAY SIT IN

YOUR LAB SEATS!)

• 3.0 x 106 + 8.0 x 106 =

(21)

Turn in scientific notation

(22)

Today…

•

ADDITION PRACTICE

•

LAB

(23)

(24)

Warm up 9/29- Grab a calculator

(3 x 10

3

) + (8 x 10

3

)= ?

(25)

(26)

EXAMPLE

(27)

•

You MUST be able to put different

numbers into scientific notation ( M

x 10

+/-n

)

•

You will only be expected to be able

(28)

(29)

Practice – ONLY EVENS

•

Use the calculator!!!

(30)

Warm up 9/30- Grab your

calculator

2 x 10

-30

- 4 x 10

-26

•

USE A CALCULATOR

5 x 10

10

+ 5 x 10

12

(31)

How to enter scientific notation into your calculator

TEXAS INSTRUMENTS

•

Look for EE on your

calculator

•

2 x 10

3



2 EE 3

•2 x 10-3  2 EE -3

•

Look for the ^ on your

calculator

•(2 x 10 ^ 3)

CANNON

•

Look for EXP on your

calculator

•

2 x 10

3

 2 EXP 3

(32)

Practice using the calculator

•

SOLVE PROBLEMS 1-6

•

Put the answers in PROPER

SCIENTIFIC NOTATION

( M x

(33)

Scientific notation: MULTIPLICATION

•

Rules for Multiplication

•Multiply the digits •Add the exponents

•Example:₍_4.2_{x 10}5

8.4

) x (2.0 x 10-2)

Multiply 4.2 x 2.0 = 8.4

Add 5 + -2 = 3

x 103

(34)

Scientific notation: DIVISION

•

Rules for Division

•Divide the digits

•Subtract the exponents

•Example: _4.2_{x 10}-7

2.1

÷ 2.0 x 10 -2

Divide 4.2 x 2.0 = 2.1

x 10

Subtract -7 - -2 = -5

(35)

Practice with MULTIPLYING AND DIVIDING-

WORKSHEET FROM YESTERDAY

• #2 A-F

_{(on a separate piece}

of paper)

(36)

Warm up 10/1- grab a calculator

4 x 1020

(2 x 1010) x (4 x 1050)

Complete WITH a

calculator

(2.5 x 10-45) ÷ (4 x 10-5)

(37)

Lab reports due tomorrow

(38)

QUIZ MONDAY OCTOBER 5

TH

•

Scientific notation quiz

Monday!!!

•

Putting numbers into and out

of scientific notation (proper

form)

•

Adding/subtracting

•

Multiplication/division

(39)

Complete without a

calculator

(40)

(6 x 1010) ÷ (4 x 10-15)

(8 x 1010) x (1 x 10-5)

(9 x 104) x (5 x 103)

(3 x 10-10) ÷ (6 x 1015)

Practice… write the following on a separate sheet of paper-

Put all answers in PROPER scientific notation form

PRACTICE USING A

(41)

Complete the following on a separate sheet of paper. WITH A CALCULATOR

Put your answers in Proper scientific notation

(2 x 104) x (4 x 103)

( 4 x 102 ) X (4 x 107

¿

(3 x 1020) x (6 x 1050)

4 x 1010

(42)

Describing Matter

QUANTITATIVELY

•Measurements are quantitative and they

represent a quantity

•Quantity: something that has magnitude,

size, or amount. (what is being measure) •Examples: mass, volume, etc.

•Unit: a quantity adopted as a standard of

(43)

UNITS

•People have been using units

for thousands of years

•The ancient Egyptians used

the units of digits (the width of a finger) and cubits (tip of the elbow to the tip of the

(44)

UNITS

•

The Romans were famous road

builders and measured distances

in "paces“ (1 pace = two

(45)

UNITS

•In England distances were

defined with reference to body features of the king. (an inch

~the width of his thumb and a foot=the length of his foot)

•Not a very good system

(nothing was standardized)

•Eventually made a standard for

the measurements

(46)

The international system of

units (SI)

•

a revised version of the metric system

•standard system of measurement used in

science.

•

All metric units are based on multiples

(47)

QUANTITY QUANTIT Y

SYMBOL

UNIT NAME UNIT Abb.

Length l Meter m

Mass m Gram/ kilogram g /

kg

Time t Seconds s

Temperat

ure T Kelvin K

Amount of a

substance

n Moles mol

Volume V centimers cubed

Liters/ Milliliters cm

3

L / mL

Pressure P Atmospheres atm

Bas e Unit

(48)

What do we use to measure?

•MASS: Balance or scale •Units = grams

•VOLUME: Graduated Cylinder, used to measure

volume of a liquid or volume of a solid through water displacement.

•units= milliliters

•LENGTH: Ruler

•units = centimeter (meters)

•can be used further to derive other

(49)

Mass is not weight.

•Mass: the amount of a substance

•An unchanged object has the same mass all over

the universe. It is constant.

•Weight- the force produced by gravity acting on

mass or the measure of the gravitational pull on mass

•The weight of an object is affected by its location

because it depends on gravity.

•On the Moon you would weigh less (less

(50)

Derived Units

•Combinations of SI base units.

•Multiplying or dividing standard units. •Area: length x width.

Volume

• _{Amount of space occupied by an object.} • _{Derived SI unit is cubic meters or m}3

• _{Liter is often used and is not a SI unit.} – _{1 Liter = 1000 cm}3

(51)

Warm up Tuesday 10/6

Match the units to the quantities they describe!

(52)

Problem Solving:

•You are on a road trip to Canada. Once

you cross the border, you notice that the speed limit is 90.

•You accelerate to 90 mph and stay at that speed.

•After a few minutes you are pulled over by

(53)

The US doesn’t us the International

System of Units (SI)

•

Canada (and almost every other country)

uses the International System of Units

•Only 3 countries don’t! (USA, Burma and

Liberia)

•

The speed limit in Canada was 90 Km/hr

(not 90 mph)!

(54)

Why do we need units?

•A number means nothing without a Unit.

•Units give sense to numerical data

•Units provide a standard for comparison

and communication

•They assist in solving a mathematical

problem, especially in chemistry, where you can follow the units to get to the answer

•They show which measurement system the

(55)

•

Mistakes made because of Units

•

In Canada, a plane ran out of fuel

because the pilot mistook liters for

(56)

•

Mistakes made because of Units

•

A 125 million dollar mistake (1.25

x 10

8

dollars!)

•The Mars Climate Orbiter, a NASA spacecraft

dipped too low into Mars’ atmosphere and was never heard from again

•Caused due to a mix up with units!!!! •The spacecraft was

programmed in Metric Units whereas the navigators were using Imperial Units during

(57)

In SI we have a set of BASIC UNITS •

Length- meter (m)

•

Mass- gram (g)

•

Volume- liter (L)

•

Time- second (s)

•

We can make these basic units smaller

or bigger by using prefixes!

(58)

common prefixes

Commonly Used Metric Prefixes

Prefix Symbo

l Multiplier

Mega M 106 100000

0

Kilo k 103 1000

Deci d 10 -1

.1

Centi c 10 -2

.01

Milli m 10 -3

.001

Micro μ 10-6 .000001

MEMORIZE THE

PREFIXES WRITTEN IN BLUE!!!!!!

PREFIX SYMBOL MULTIPLIER EXAMPLE

Tetra T 1012 1 000 000 000 000 1 tetrameter (Tm) = 1 x 1012 m

Giga G 109 1 000 000 000 1 gigometer (Gm)= 1 x 109 m

Mega M 106 1 000 000 1 megameter (Mm) = 1x106 m

Kilo k 103 1000 1 kilometer (km) = 1000 m

Hecto h 102 100 1 hectometer (hm) = 100 meters

Deka da 101 10 1 dekameter (dam) = 10 m

BASE 100 1 1 meter

Deci d 10-1 1/10 1 decimeter (dm) = 0.1 m

Centi c 10-2 1/100 1 centimeter (cm) = 0.01 m

Milli m 10-3 1/1000 1 millimeter (mm) = 0.001 m

Micro μ 10-6 1/1 000 000 1 micrometer (μm) = 1 x 10-6 m

Nano n 10-9 1/ 1 000 000 000 1 nanometer (nm) = 1x10-9 m

Pico P 10-12 1/1 000 000 000 000 1 picometer (pm) = 1x10-12 m

(59)

Examples… Look at your conversion

sheet!

1. Kilogram 1 kg= 103 g = 1000 g 2. gigameter 1 Gm = 109 g

3. microliter = 1 µL = 10-6 L or 106 µL = 1 4. Millisecond  1 ms = 10-3 s

(60)

Example: How many Bubs in a

HectoBub?

1 hectoBub = 100 Bubs!

1 Bub

1 HectoBub

=

(61)

(62)

Conversion factors

•

Quantities can usually be expressed in

several different ways



THINK OF

MONEY.

•

1 dollar= 4 quarters= 10 dimes= 20

nickels= 100 pennies

•

They are all expressions (measurements)

(63)

Conversion factors

•Conversion Factors: a ratio of equivalent

measurements that can be used to convert from one unit to another

•EXAMPLE 1- MASS

• 1 gram= 100 centigrams is a

conversion factor

(64)

•

Conversion factors involve an

equality of two things.

•

Any equality can be written as a

conversion factor

•

1000 mg = 1 g

•

1 dozen = 12 of something

•

3 ft = 1 yard

(65)

•

Conversion factors are written like

division problems

•

2.54 cm = 1 inch

•

the conversion factor would be:

(66)

•

How would you write the following

conversion factors…

•

4 quarters = 1 dollar?

•

or

(67)

Conversion Factors Example:

Length

_• _{The same length can be expressed in multiple}

ways.

• _{1000 mm= 100 cm= 10 dm}_{= 1 meter}

= .001 km 1 m 1 meter 1oo centimeters

=

1

m

100

cm

smaller number

LARGER UNIT

LARGER

NUMBER smaller unit

10 20 30 40 50 60 70 80 90

(68)

Warm up 10/7

•Which unit is bigger? Use the yellow sheet

to help you!

(69)

When do we use conversion

factors?

•Conversion Factors are useful in solving

problems where you are going from one unit

to another

•When a measurement is multiplied by a

conversion factor, the numerical value is

changed, but the actual size of the quantity

measured remains the same. _{$4 bill x 4 quarters}

$1 bill

= 16

(70)

common prefixes

Commonly Used Metric Prefixes

Prefix Symbo

l Multiplier

Mega M 106 100000

0

Kilo k 103 1000

Deci d 10 -1

.1

Centi c 10 -2

.01

Milli m 10 -3

.001

Micro μ 10-6 .000001

MEMORIZE THE

PREFIXES WRITTEN IN BLUE!!!!!!

PREFIX SYMBOL MULTIPLIER EXAMPLE

Tetra T 1012 1 000 000 000 000 1 tetrameter (Tm) = 1 x 1012 m

Giga G 109 1 000 000 000 1 gigometer (Gm)= 1 x 109 m

Mega M 106 1 000 000 1 megameter (Mm) = 1x106 m

Kilo k 103 1000 1 kilometer (km) = 1000 m

Hecto h 102 100 1 hectometer (hm) = 100 meters

Deka da 101 10 1 dekameter (dam) = 10 m

BASE 100 1 1 meter

Deci d 10-1 1/10 1 decimeter (dm) = 0.1 m

Centi c 10-2 1/100 1 centimeter (cm) = 0.01 m

Milli m 10-3 1/1000 1 millimeter (mm) = 0.001 m

Micro μ 10-6 1/1 000 000 1 micrometer (μm) = 1 x 10-6 m

Nano n 10-9 1/ 1 000 000 000 1 nanometer (nm) = 1x10-9 m

Pico P 10-12 1/1 000 000 000 000 1 picometer (pm) = 1x10-12 m

(71)

What is the pattern/rule?

(72)

What is the pattern/rule?

(73)

What is the missing piece?

(74)

What is the missing piece?

(75)

What is the answer….

(76)

What is the answer….

(77)

How would you fix this?

(78)

(79)

What did we learn

• If you have the same thing on

(80)

Observe….

(81)

It’s the same with units!

•

How can I go from one unit to

another?

•

Cancel the Units!!!

(82)

Warm up 10/9

What is the missing piece?

=

?

(83)

Remember….

• If the same things are on

(84)

CONVERSION PROBLEMS

How many LITERS (L) are in 5 mL?

•

What UNIT do I START with?

•

MILILITERS (mL)

•

What UNIT do I want to END with?

(85)

𝟓𝐦𝐋

CONVERSION PROBLEMS

Starting unit: mL ending unit: L •You want to CANCEL out mL!!!

• Which conversion factor should you use?

or

(86)

CONVERSION PROBLEMS

•

How do we calculate the actual

answer???

•Multiply by what’s on the top

•Divide by what’s on the bottom

•

_{5 x 1 ÷ 1000 = 0.005 =}

_{in scientific}

notation?

(87)

What if I wanted to find out how many

KILOLITERS are in 0.5 mL

Starting unit: mL Ending unit: kL

Conversion Factors: or & or

_{5 x 10}

_-6

_k

_L

(88)

Dimensional analysis activity

•Work in PAIRS or in groups of 3 (no more than

3 people at each table!)

•Cut out all of your POSSIBLE conversion

factors

•You will not use each one, some will be used more than once.

•Set up the problem first

•Use the given conversion factors, to help you set up each problem.

•Remember, set up your conversion factors so that your units cancel!

(89)

WARM UP 10/9

•SET UP the following conversion problems using the

CORRECT conversion factors (make sure your units cancel!). Use your yellow sheet to help you!

•

How many mL are in 0.425 L?

0.425 L × ?

(90)

Helpful hints…

•If you are converting from a BASE UNIT _

PREFIX or a PREFIX  BASE UNIT

•It is usually a ONE STEP PROBLEM (only 1

conversion factor)

•If you are converting from a PREFIX  PREFIX •It is usually at least a 2 STEP PROBLEM (2 or

more conversion factors)

(91)

(92)

What if I wanted to find out how many

KILOLITERS are in 0.5 mL

Starting unit: mL Ending unit: kL

Conversion Factors: or & or

_{5 x 10}

_-6

_k

_L

(93)

Today

•

Domino activity: 12-15 minutes to

finish the set ups

•

Notes

(94)

Warm up 10/13

• How many centimeters are in 1

meter?

• How many grams are in one Mg?

(95)

Warm up 10/13

•How many centimeters are in 1 meter?

•100 cm = 1m

•How many grams are in one Mg?

•1 000 000 grams = 1 megagram

•106 grams = 1 megagram

•How many nL are in 1 L?

(96)

(97)

Test WEDNESDAY 10/21

•SI Units

•Metric Conversions and Conversion Factors •Memorize_

•106 µm = 1 m

•1000 mm = 1 m •100 cm= 1 m

•10 dm = 1 m •100 m= 1 hm •1000 m = 1 km

(98)

Today…

•

Dimensional Analysis Notes

and Practice

•

Finish the Domino Activity

•

Calculations will be homework

(99)

DIMENSIONAL ANALYSIS

•Dimensional analysis is a way to analyze and

solve problems in chemistry using the units (dimensions) of measurement.

•Steps for Solving Problems with dimensional

analysis

1.Identify what you are given (or starting with)

in the problem

2.Determine what you are trying to solve for or

find (units)

3.Determine your conversion factor

4.Set up the problem so that your units cancel! 5.Multiply by the numbers on top, and divide by

(100)

analysis

1. Identify what you are given (or starting with) in the problem

Starting Quantity

(101)

analysis

2. Determine what you are trying to solve for or find (units)

Starting

(102)

•Steps for Solving Problems with dimensional analysis • 3. Determine your conversion factor

• 4. Set up the problem so that your units cancel!

Starting

UNIT

=

Ending _UNIT

(ending unit)

(starting unit)

(103)

•

Steps for Solving Problems with dimensional

analysis

•

5. Multiply the numbers on top, and divide by

any numbers on the bottom

Starting

UNIT

=

Ending _UNIT

FACTOR

(starting unit)

(ending unit)

CONVERSION

(104)

Example 1: Dimensional analysis

•Calculate the number of minutes you are in school for 1

school day. A school day is approximately 6.5 hours long.

1. What information am I given? A school day is 6.5 hours long

2. What am I trying to find? How many minutes are in 6.5 hours

3. Conversion factor? 1 hour = 60 minutes, or Solve 6.5 x

60 ÷ 1 = 390 minutes

hours

6.5

=

min

60 min

1 hour

390

(105)

Helpful TIPS for metric conversions…

•Setting up a Conversion Factor…

•Give the Larger unit a value of 1

•The smaller unit with then have a value greater than 1

•Example: kilograms and grams

•Kg is the LARGER unit  1

•Grams are the smaller unit. Multiple grams make up 1 kg

kg

= grams

(106)

Helpful TIPS for metric conversions…

•If you are converting from a… BASE UNIT

 PREFIX or a PREFIX  BASE UNIT

•It is usually a ONE STEP PROBLEM (only 1 conversion

factor)

•_{If you are converting from a…}

PREFIX  PREFIX

•It is usually a MULTI-STEP problem (2 or more

conversion factors)

•Prefix  Base: Convert to your base first!

(107)

Test WEDNESDAY 10/21 (maybe thurs)

•SI Units

•106 µm = 1 m

•1000 mm = 1 m •100 cm= 1 m

•10 dm = 1 m •100 m= 1 hm •1000 m = 1 km

(108)

Warm up 10/15

• How many cm

(109)

WARM UP 10/16- get kahoot ready (don’t

use your yellow sheets!)

(110)

Test WEDNESDAY 10/21 (maybe thurs)

•SI Units

•106 µm = 1 m

•1000 mm = 1 m •100 cm= 1 m

•10 dm = 1 m •100 m= 1 hm •1000 m = 1 km

(111)

(112)

Challenge problem from Lewis Caroll’s Through the Looking Glass

•If there are 5 FRUMIOUS BANDERSNATCHES, how many JABBERWOCKS are there?

•There are 20 tum tum trees in a tulgey wood.

•In each tulgey wood is one frumious Bandersnatch. •There are 5 slithy toves in 2 borogoves.

•There are 2 mome raths per Jabberwock.

(113)

Warm up 10/19

•Convert 50 miles/hour to km/hour

(114)

Converting Temperature

There are three temperature scales

•Fahrenheit Scale (oF)

• water boils at 212 oF and freezes at 32 oF

•normal body temp is 98.6 oF.

•Celsius Scale (oC ): like the metric system, it is bases

on powers of 10.

• water boils at 100 oC and freezes at 0 oC.

•Kelvin Scale (K), no degree symbol.

(115)

Converting Temperature

•Celsius to Kelvin: formula: K = °C + 273 •Ex: 45 °C to K

• K = 45 + 273

• Answer: 318 K

•Kelvin to Celsius: °C = K - 273 •Ex: 307 K to oC

•°C = 307 – 273 •Answer: 34 °C

(116)

Converting Temperature

°C to °F

: °F = 1.8 (°C ) + 32

•Ex: 27 oC to oF

•°F = ( 1.8 x 27 ) + 32

•°F = 48.6 +32 = 80.6 °F

°F to °C: °C = ( °F - 32 ) / 1.8

•Ex: 149 oF to oC

(117)

Precision vs Accuracy

•Accuracy: The closeness of measurements to the

correct or accepted value of the quantity measured

• Precision: the exactness of a measurement •Values that are close to one another, but not

(118)

This pattern is both precise and accurate. The darts are tightly

clustered and their average position is the center of the bull's eye.

Precise and Accurate

Accurate, Not Precise

This is an accurate pattern, but not precise. The darts are not clustered,

(119)

Neither Precise Nor Accurate

Precise, Not Accurate

This is a random like pattern, neither

precise nor accurate. The darts are not clustered together and are not near the bull's eye.

This is a precise pattern, but not accurate. The darts are clustered

(120)

(121)

Percent Error

•Quantitative comparison of an experimental value to

the theoretical (accepted/known) value.

(122)

A student measures the mass and volume of a

substance and calculates its density as 1.40 g/mL. The correct density (accepted value) is 1.30 g/mL.

•What is the % error?

Percent Error =x 100

Percent Error = x 100 =

Percent Error = x 100 = .0769 x 100 = 7.69%

1.30 g/mL