Chem final Flashcards
1
Q
1-2 letter abbreviations for elements
A
Most are straightforward (O = oxygen, Si = Silicon, etc)
2
Q
Elements based on Latin or Greek names
A
-Pb = Lead
-Hg = Mercury
-Cu = Copper
-Fe = Iron
=K = Potassium
-Sb = Antimony
-Ag = Silver
Au = Gold
3
Q
All matter: Mixtures
A
- If the matter can be separated by a physical process then it is a mixture.
- If the matter can not be separated by a physical process it is not a mixture
4
Q
All matter: Compounds or elemnets
A
- If the matter is not separated by a physical process it turns into a pure substance.
- If the substance can be broken down into simpler ones by chemical means, then it is a compound.
- If it can not be broken down into simpler ones by chemical means then it is an element
5
Q
Classification of matter
A
- The four components of matter are solids, liquids, gases, and plasmas
- Matter can be divided into pure substances and mixtures.
- Pure substances may be elements (containing atoms of the same type–for instance, silicon (Si) or compounds (containing 2 or more different types of atoms–for example, silicon dioxide (SiO2)
- Mixtures may be heterogeneous (with a composition that caries throughout, such as gravel) or homogeneous (with a unifrm composition throughout, such as solutions of sugar dissolved in water)
6
Q
Molecule
A
- A space-filling model for a water molecule is H2). There’s two hydrogen atoms, and one oxygen atom.
- A molecule is a fixed number of atoms held together by chemical bonds in certain spatial arrangement .
- The chemical formula symbolically represents the type and number of each element present
7
Q
Classifying matter: Compounds
A
- Carbon dioxide
- Cocaine.
- Water
- Table salt
8
Q
Classifying matter: Element
A
- Nickel.
- Fluorine
9
Q
Classifying matter: Mixture
A
- Soap.
- Sea water
10
Q
Atoms: Compounds
A
- Ionic compounds are composed of oppositely charged ions. Electrons are either added or subtracted from atoms to form ions.
- Molecular compounds are composed of molecules, which ate made up of atoms.
- The four states of matter, elements, compounds, and mixtures are on the macroscopic scale (can view with the naked eye), individual molecules, ions, and atoms are on the sub-microscopic or nanoscale (one-billionth of a meter)
11
Q
Example: Different compounds containing the same element will have different physical and chemical properties
A
- Fe: Magnetic
- Fe2O3: Non magnetic
12
Q
Properties of subatomic particles: Prton
A
- Relative charge: +1
- Relative mass: 1
- Actual mas, kg: 1.67 x 10^-27
13
Q
Properties of subatomic particles: Neutron
A
-Relative charge: 0
-Relative mass: 1
Actual mass, kg: 1.67 x 10^-27
14
Q
Properties of subatomic particles: Electron
A
- Relative charge: -1
- Relative mass: 0**
- Actual mass, kg: 9.11 x 10^-31
15
Q
**0
A
This value is zero when rounded to the nearest whole number. it does have a mass, though it’ve very small
16
Q
Properties of subatomic particle
A
- Most of the mass in an atom is found in the nucleus.
- Protons and neutrons are found in the nucleus.
- Electrons are located outside the nucleus
17
Q
Atomic number (Z)
A
the number of protons (nuclear charge)
18
Q
Mass number (A)
A
The sum of the protons and neutrons
19
Q
Electrical conductivity
A
- Metals are electrically and thermally conductive.
- Electrical conductivity involves the movment of electrons through the 3-D structure of a conductor
20
Q
Cu
A
- Atomic number = 29
- Therefore ti contains 29 protons (29+ charge).
- To balance the charge, it contains 29 lectrons (29 - charge).
- Mass number = number of protons + number of neutrons (0 charge)
- Number of neutrons = 63 -29 = 34
21
Q
Allotrope
A
Is two or more forms of the same element that differ in their chemical structure and therefore their properties
22
Q
Atomic composition of the earth’s crust
A
- Al: 8%
- Si: 28%
- O: 47%
- Fe: 5%
- Group 1-2: 11%
- Other: 1%
23
Q
Non-zero digits are significant
A
For instance, 1.55 g = 3 significant figures
24
Q
All zeroes embedded between non-zero digits are significant
A
For instance, 1.003 mL = 4 significant figures
25
Trailing zeroes are significant
For instance, 1.000 g = 4 significant figures
26
Leading zeroes are not significant
For instance, 0.00305 mL = 3 significant figures
27
Addition/subtraction
- Answer is based on the smallest decimal places.
| - For instance, 1.003 + 0.2 + 0.001 g = 1.2 g
28
Multiplication/division
- Answer based on the smallest number of significant figures.
- For instance, 1.002 cm times 0.005 cm = 0.05 cm = 0.005 cm^2
29
Scientific notation
```
11000 = 1.1 x 10^4
0.00021 = 2.1 x 10^-4
0.001021 = 1.021 x 10^-3
1730 = 1.73 x 10^3
**The same number of significant figures on both sides of each example
```
30
Scientific notation: Moving decimals
Very small numbers move the decimal to the right, large numbers move the decimal to the left
31
Moving decimals
```
0.00000012 = 1.2 x 10^-7
2300000000 = 2.3 x 10^9
```
32
12N silicon (Si)
- 99.9999999999
- An analogy for the 12N purity of silicon: Stack 170 yellow tennis balls from Earth to the moon, replace 1 yellow tennis ball with a red one, this reflects how few impurities are present in this ultra-high purity silicon
33
From silicon to computer chip
- Ultra-high purity silicon (5N, 7N, or 12N purity)
- At high temperatures, silicon is fabricated into cylinders (ingots) and sliced into wafers
- Hundreds of processing steps are used to fabricate a computer chip on the surface of silicon wafers
- Chips are removed from the wafer and tested
- The chips that are tested satisfactorily are sealed and packaged
34
Chip testing
Technicians work inside "clean rooms" and wear "bunny suits' to prevent contamination by dust particles
35
Size comparison
- To relate how small the components of chips are, the scale bars in the bottom electron microscope images are comparable to:
a. Diameter of a coud water droplet
b. Diameter of mold spores
c. Diameter of a human hair fiber
d. Diameter of beach sand
e. Thickness of a human cornea
f. Diameter of a pinhead
g. Diameter of a pupil
36
Transistors
Computer chips contain billions of tiny components of these and are sued to perform the calculations needed by our coputers and portable electronic devices
37
Prince Rupert of the Rhine, Duke of Cumberland, KG, PC, FRS (17 December 1619- 29 November 1682)
German army officer, admiral, scientist and colonial governor.
-He firs came to promience as a Cavalier cavalry commander during the English Civil War
38
Sustainability: Three pillars
- Environmental: Pollution prevention, natural resource use
- Social: Better quality of life for all members of society
- Economic: Fair distribution and efficient allocation of resources
39
The composition of air
It's a mixture: A physical combination of two or more substances present in variable amounts
40
What's in a breath
In addition to nitrogen, oxygen, and other colorless gases, there are harmful nitrogen oxides and particulate matter that contribute to air pollution
41
Air inversions
- Cooler air can be trapped beneath warmer air due to weather conditions
- Pollutants often accumulate in the cooler air of an inversion layer.
- This situation is worsened when air flow is limited, such as in cities surrounded by mountains
42
Visualizing the molecules in air
- A molecule is a fixed number of atoms held together by chemical bonds in a certain spatial arrangement.
- The chemical formula symbolically represents the type and number of each element present.
- Chemists use three viewpoints to study and understand matter, macroscopic, symbolic, and particulate
43
Molecular structures
The particulate view of matter shows the 3-D molecular structure, with atoms color-coded
44
Naming binary compounds of nonmetals
- Prefixes are used to designate the number of each type of element:
- N2O = dinitrogen monoxide (also known as nitrous oxide, or laughing gas)
- P2O5 = diphosphrous pentoxide
45
Risk assessment
Evaluating scientific data and making predictions in an organized manner about the probabilitie of an occurrence
- Toxicity: Intrinsic health hazard of a substance
- Exposure: The amount of the substance encountered
46
Parts per hundred (percent)
Atmosphere is 21% oxygen = 21 oxygen molecules per 100 molecules and atoms in air
47
Parts per million (ppm)
0.4 ozone molecules/1 x 10^6 molecules and atoms in air
48
Parts per billion (ppb)
30 sulfur dioxide molecules/ 1 x 10^9 molecules and atoms in air
49
21 % means 21 parts per hundred...
- Means 210 parts per thousand.
- Means 2,100 parts per ten thousand.
- Means 21,000 parts per hundred thousand.
- Means 210,000 parts per million
50
These gases represent the most harmful for our health and the health of our planet
- Carbon monoxide.
- Ozone.
- Sulfure dioxide (SO2) and nitrogen dioxide (NO2)
- Particlate matter (PM)
51
Air quality monitoring and reproting
The average concentration of air pollutants in the Unoted States have decreased dramatically since 2000
52
The number of unhealthy days per year
Although air quality has improved in recent years, on average, people in some metropolitan areas breathe air containing unhealthy levels of pollutants
