chapter 1.powerpoint 1
TRANSCRIPT
Dr. LAILA AL-HARBI
Measurement SI units Mass and weight Volume Temperature scales
Chapter 1The study of change
Dr. LAILA AL-HARBI
By the end of this chapter you should: Know the 7 SI basic units and their prefixes. Be able to convert from one unit to other. Know to derive units from the 7 SI basic units. Common units (L & mL) Know the temperature Scales
Objectives
Dr. LAILA AL-HARBI
Chemistry is the study of matter and the changes it undergoes
There are three states of matter
Introduction
solidliquid
gas
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1.7 Measurement and UnitsThe International System of units (SI Units)
used for commerce and science around the world
5
The SI unit of mass is
(a) The pound
(b) The gram
(c) The kilogram
(d) The mole
Examples
The Kg is the SI unit of
(a) length
(b) mass
(c) temperature
(d) current
Dr. LAILA AL-HARBI
A) use numerical line االعداد خطB) use transfer factor التحويل معامل
أو مضاعفتها و األساسية الوحدة من للتحويلأو االعداد خط استخدام يمكننا المشتقات
الطريفين ) بضرب التحويل معامل استخدامالوسطين ( .في
To transfer between perifexs
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أو مضاعفتها و االساسية الوحده من للتحويلاستخدام أو االعداد خط استخدام يمكننا المشتقات ) ( و الوسطين في الطريفين بضرب التحويل معاملالطريقتين أن كما الطريقتيين بين تخلطي ال لكنبطريقة بنفس استخدامها تم اذا النتيجة نفس يعطوا
صحيحة.
TGMKSIdcmµnp
103 103103103 103 103 101010 103
1012109
106
103
1012
109106
103102 10
التحويل معامل التحويل معامل
الوحده تزيد االتجاه بهذا
صغيرة وحدة كبيرة وحدة
نقسم كبير الى صغير من من , ÷للتحويل للتحويلنضرب صغير الى × كبير
Dr. LAILA AL-HARBI
I. Convert 134 pm to m?II. How many meters are in 134 pm?
نقسم كبير الى صغير من ÷ للتحويل
1 pm = 1×10-12 m134 pm = ?? m
االعداد خط باستخدام الحل
وسطين في طرفين الجدول باستخدام الحل
134 ×1×10-12 m = 1.34×10-10 m
Examples The SI prefixes giga and micro represent, respectively:
A. 10-9 and 10-6. B. 106 and 10-3. C. 103 and 10-3. D. 109 and 10-6.
The SI unit of mass is
(a). The pound
(b). The gram
(c). The kilogram
(d). The mole.
Dr. LAILA AL-HARBI
Dr. LAILA AL-HARBI
How many microseconds are in a second?(a). 1 x 10-1
(b). 1 x 10-6
(c). 1 x 10-15
(d). 1 x 10 6
Explanation: Since the prefix micro means 1 x 10-6, there will be 1 x 10 + 6 microseconds in one second.
1 µs= 1 x 10 -6 sx µs = 1 s
s µs
1 10 6 x 1 x 10 6 µs
Dr. LAILA AL-HARBI
Which of the following is the smallest distance? (a) 21 m → 21m (b) 2.1 x 102 cm → 2.1m (c) 21 mm → 0.021 m (d) 2.1 x 104 pm → 2.1 x 10-8 m
Put all of them in the same unit
Explanation: Even though 2.1 x 104 is the largest number in this question, the units of pm (picometers) are the smallest units here, making it the smallest distance.
Example
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A) 6.0 km is how many micrometers?
Solution 1
1 km = 103 m
6 km = x = 6 × 103 m
1µm = 1× 10-6 m
x = 6 × 103 m
x = 6 × 109µm Explanation: convert first to meter then from meter to micro
( two steps solution )
km µm
×6 109 6 × 109
Dr. LAILA AL-HARBI
Example The diameter of an atom is
approximately 1 10-7 mm. What is this diameter when expressed in nanometers?
A. 1 10-18 nm B. 1 10-15 nm C. 1 10-9 nm D. 1 10-1 nm
= 1× 10-7 × 1 × 106 = 1 × 10-1 nm = 0.1 nm
Example
Which of these quantities represents the largest mass?
A. 2.0 102 mg B. 0.0010 kg C. 1.0 105 g D. 2.0 102 cg Put all of them in the same
unit A) 0.2 gB)1 gC) 0.1 gD) 2 g
Dr. LAILA AL-HARBI
are defined in terms of the seven base quantities via a system of quantity equations.
The SI derived units for these derived quantities are obtained from these equations and the seven SI base units. For example
Area = width x length Unit of width = m Unit of length = m Unit of Area = m× m = m2
SI derived units
Treat units like numbers
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Volume –
Volume = width × length × heights = m × m × m = m3
SI derived unit for volume is cubic meter (m3)
Common unit of volume is liter (L) and milliliter (ml)
The relation ship between liter (L) and ml (1L= 1000mL)
The relation ship between liter (L) and metric system
1 L = 1 dm3
The relation ship between milliliter (ml) and metric system
1 mL = 1 cm3
1 cm3 = (1 x 10-2 m)3 = 1 x 10-6 m3
1 dm3 = (1 x 10-1 m)3 = 1 x 10-3 m3
Dr. LAILA AL-HARBI
Example (1)
Example (2)
How many liters are in 25 dm3 ?
Science 1L = 1 dm3
25 dm3 = 25L
How many milliliters are in 32 cm3 ?
Science 1mL = 1 cm3
32 cm3 = 32 mL
Example (3)
How many liters are in 250 cm3 ?
Science 1L = 1 dm3
and 1mL = 1 cm3
250 cm3 = 250 mL L → mL 250/1000 = 0.25 L
Dr. LAILA AL-HARBI
How many cubic centimeters are there in exactly one cubic meter?
A. 1 10-6 cm3
B. 1 10-3 cm3
C. 1 10-2 cm3
D. 1 106 cm3
Solution (1m )3 = (cm )3
1m3 = (1 102)3 cm 3
1m3 = 1 106 cm3
Examples
The diameter of an atom is approximately 1 10-7 mm. What is this diameter when expressed in nanometers?
A. 1 10-18 nm B. 1 10-15 nm C. 1 10-9 nm D. 1 10-1 nm
Dr. LAILA AL-HARBI
Mass is the measure of the amount of matter in an object.
SI unit of mass is the kilogram (kg)
1 kg = 1000 g = 1 x 103 g
Weight is the measurement of the pull of gravity on an object.
The Mass of an object doesn't change when an object's location changes. Weight, on the other hand does change with location.
Chemist are interested primarily in mass
weight = c x mass
Mass and Weight
The weight of man on earth is 50 pounds.is 8.25 pounds on moon
Dr. LAILA AL-HARBI
Density is defined as the amount of matter in a given amount of space.
SI derived unit for density is kg/m3
common units of density are g/mL , g/L
Density decrease with temperature (g/ml )g/cm3 for liquid and solids g/L = 0.001g/ml for gases
Because density of gases are very low
Density
The density of copper is 8.94 g/cm3.
density = mass
volume
Dr. LAILA AL-HARBI
Example 1.1
A piece of Gold metal has a volume of 15.6 cm3, with a mass of 301 g What is its density?
A piece of platinum metal with a density of 21.5 g/cm3 has a volume of 4.49 cm3. What is its mass?
d = mV
m = d x V
= 21.5 g/cm3 x 4.49 cm3 = 96.5 g
d = mV
301 g/ 15.6 cm3 = 19.3 g/ cm3
Dr. LAILA AL-HARBI
Example 1.2
The density of mercury is 13.6 g/mL has a volume of 5.50 mL. What is its mass?
The density of sulfuric acid is 1.41 g/mL has a volume of 242 mL. What is its mass?
d = mV
m = d x V
= 1.41 g/mL x 242 mL = 341.22 g
d = mV
m = d x V
= 13.6 g/mL x 5.50 mL= 74.8 g
Dr. LAILA AL-HARBI
Fahrenheit °F: °F = [ (9/5) × °C] + 32 Celsius °C: °C = (5/9) (°F - 32) Kelvin K: K = °C + 273.15
Temperature Scales
25
Temperature Units Conversion1. Degrees Celsius 0C: Scale 0 → 100 Thus:
100 divisions or 100 degrees2. Kelvin K: Scale 273 → 373Thus: 100 divisions or 100 degrees1K = 1 C3. Degrees Fahrenheit 0F : Scale from 32→ 212 Thus: 180 divisions or 180 degreesThus: the size of degree in 0F scale is only 100/180
or5/9 of a degree on the 0C scale 10F = (5/9) 10C
Dr. LAILA AL-HARBI
Convert 224 0C to degrees Fahrenheit? °F = (9 0F /5 0C) × °C + 32 [°F = (9 0F /5 0C) × 224 °C] + 32 0C = 435 0F
Convert -452 0F to degrees Celsius. °C = (5 0C /9 0F) (°F - 32 0F) °C = (5 0C /9 0F) (-452 °F - 32 0F) = -269 0C
Convert -38.9 0C to degrees Kelvin.. ° K = [-38.9 °C + 273.15 °C ] × 1 K/ 1 0C = 234.3 K
Example 1.3