Course lecturer : Dr. Altijana Hromić Jahjefendić · Chemistry is the study of properties of...
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Course lecturer : Dr. Altijana Hromić-Jahjefendić
Transcript of Course lecturer : Dr. Altijana Hromić Jahjefendić · Chemistry is the study of properties of...
Course lecturer : Dr. Altijana Hromić-Jahjefendić
Assis. Prof. Dr. Altijana Hromić-Jahjefendić
Born in Sarajevo
Studies in Austria
Came back
I am not a monster!
Quizzes (2x) 2 x 5% = 10%
Midterm exam Lab tutorials (6x)
30% 20%
Final exam 40%
Total 100%
Assistant: Jasmin Sutkovic, MSc
No tutorials during midterm week
First quiz: 28.10.2018 (Monday) – everything from the first lecture
Midterm exam: TBD– from the first lecture
Book chapters: 1 and 2
Pages: 2-23 and 23-57
Chemistry is the study of properties of substances and how they react with one another .
It is an experimental science based of the scientific method!
Hunderds of materials that we use EVERY DAY , directly and indirectly, are the products of chemical research.
◦ For example: Plastics , Computer Chips, paper, fuels, cement,
ceramics, sollar cells, Cosmetics and so on.........
WE NEED CHEMISTRY TO UNDERSTAND OUR ENVIRONMENT!!
Why we study Chemistry ?:
Digestion..
Cooking..
When you write with ink on paper..!
Steel is 94% iron and 6% carbon. The carbon forms complex bonds making steel so strong that you can bend an iron crowbar, but not a steel one.
ANYTHING that burns is undergoing a chemical reaction and almost always creates some form of carbon as waste.
Hemoglobin transports oxygen to the tissues and carbon dioxide
to the lungs.
Chemistry is the study of the composition, structure, properties, and reactions of matter.
Matter - another word for all the substances that make up our world. Has mass and takes up space
Chemistry is not done only in lab…
Actually, chemistry happens all around you every day and has an impact on everything you use and do.
You are doing chemistry when you cook food, add bleach to your laundry, or start your car.
A chemical reaction has taken place when silver tarnishes or an antacid tablet fizzes when dropped into water
A chemical is a substance that always has the same composition and properties wherever it is found.
All the things you see around you are composed of one or more chemicals.
Scientific method…
Help to explain how scientists think….
As a child: touching and tasting
As a teenager: asking questions
As an adult: reading, searching, investigating
1.Observations- look around you and ask yourself question !!
2. Hypothesis - Propose a hypothesis, which states a possible explanation of the observations.
The hypothesis must be stated in such a way that it can be tested by experiments.
3. Experiments.
4. Conclusion. When the results of the experiments are analyzed, a conclusion is made as to whether the hypothesis is true or false.
If we gather enough data about our subject we will be able to form a HYPOTHESIS.
◦ Hypothesis is a proposed explanation for an observation, phenomenon, or scientific problem that can be tested by further investigation!
To test the hypothesis we perform EXPERIMENTS .If the experiments support the hypothesis we will perform another experiments(under various conditions) to verify our statement.
After many confirmed experiments( the results are reproducible) we can CONCLUDE and state a LAW or Scientific law . ◦ A law simply says what happens but doesn't explain it (why
this happens).
Once a Law has been formulated, scientist try to develop a THEORY (unifying principle) that explains the law based on experimental methods( why nature behaved as it does ).
The theory can develop by time because new facts may arise.
Scientific method
Chemistry around us
Hypothesis
Scientific method
Course lecturer : Dr. Altijana Hromić-Jahjefendić
Metric system of measurements
Commom measuring system
The International System of Units (SI) is official system of measurements
Except in USA
In chemistry we use both: metric and SI (length, volume, mass, temperatute etc.)
The metric and SI unit is the meter (m)
Other units which are used in some countries are inch, yard, centimenter
1 m = 100 cm
1 m = 39.4 in
1 m = 1.09 yd
2.54 cm = 1 in
Is the amount of space a substance occupies
A liter (L) is standard measurement
In lab we work with units of vollume that are smaller
Milliliter (mL)
Is a measure of the quantity of material it contains
SI unit is kilogram (kg)
In the metric system the unit is gram (g)
In the lab we are using smaller units than kilogram
Tells us how hot or cold is something
To determine if we have fever
In the metric system is measured using Celsius temperature (°C)
In SI system is measured using Kelvin (K) temperature
SI and metric system unit is second (s)
We measure time in units like minutes (min), hours (h), days or years (yr)
Measured numbers – obtained after quantity masurement (height, weight, temperature)
Significant figures – all digits including the estimated digit (zero may or may not be significant depending on its position in a number)
Calculator
Faster
Can not think for you
Enter the number correctly, press the correct function key etc.
Example: room of 5.52 m x 3.58 m
Each of measurement has 3 significant figures
Buying a carpet needs the surface
19.7616 in the display
Too many numbers
The displayed number must be rounded off
19.8
Special feature of SI as well as the metric system is prefix
Can be placed in front of any unit to increase or decrease its size by some factor of 10
Prefix + meter
Centimeter (cm)
Millimeter (mm)
We can compare the lengths
Equalities – show the relationship between two units that measure the same quantity
1 m = 100 cm
1 m = 1000 mm
1 cm = 10 mm
Liter
In lab (medical lab) is dL
Also equalities
1 L = 10 dL
1 L = 1000 mL
Sometimes also cubic centimeter (cm3)
Has same volume as milliliter
1 cm3= 1 mL
Mass ususally recorded in kilograms
Laboratory tests in milligrams, grams or micrograms
1 kg = 1000 g
1 g = 1000 mg
If we compare the mass of the object to its volume we obtain density
Density = mass of substance/volume of substance
Every substance has a unique density
Example: lead has density of 11.3 g/mL and cork has density of 0.26 g/mL
If an object is less dence than a liquid, the object floats when placed in that liquid
Metals have higher density
Gases have low
Example: HDL (“good cholesterol”)
Density: mass of HDL sample/volume of HDL sample
0.258 g/0.22 mL = 1.2 g/mL
The volume of solid can be determined by volume displacement
When a solid is completely submerged in water, it displaces a volume that is equal to the volume of the solid
Units of measurement
Rounding off
Density
