Chapter 3. Stoichiometry: Calculations with Chemical Formulas and
... (6.022 x 1023) of “building blocks” (atoms for most elements, molecules for molecular substances, formula units for ionic substances) in the same fashion as a dozen means 12 (eggs, people, items, etc.) Be able to appreciate how important the concept of a mole is Limiting reagents concept can be diff ...
... (6.022 x 1023) of “building blocks” (atoms for most elements, molecules for molecular substances, formula units for ionic substances) in the same fashion as a dozen means 12 (eggs, people, items, etc.) Be able to appreciate how important the concept of a mole is Limiting reagents concept can be diff ...
Cold encounters: Electrons and molecules
... 500 ilK. When cold electrons encounter molecules, they can be elastically scattered, they can excite rotation and vibration in the targets or they can cause the formation of negative ion products, a process called dissociative attachment (DA). Experiments Two types of experiment have been developed. ...
... 500 ilK. When cold electrons encounter molecules, they can be elastically scattered, they can excite rotation and vibration in the targets or they can cause the formation of negative ion products, a process called dissociative attachment (DA). Experiments Two types of experiment have been developed. ...
Lectures 7-9
... If an atom is struck by a photon that has enough energy, it will absorb the photon. This puts the atom into an excited state. (An atom that has absorbed no energy from external sources is said to be in its ground state.) ...
... If an atom is struck by a photon that has enough energy, it will absorb the photon. This puts the atom into an excited state. (An atom that has absorbed no energy from external sources is said to be in its ground state.) ...
Chapter 3: Introduction to chemical formulas and reactivity
... formula weight. Interconvert between number of particles, moles, and mass. Understand the term percent composition and know how to calculate the percent composition of an element in a formula. Use percentage composition to determine the empirical formula of a substance. Understand how to formulate a ...
... formula weight. Interconvert between number of particles, moles, and mass. Understand the term percent composition and know how to calculate the percent composition of an element in a formula. Use percentage composition to determine the empirical formula of a substance. Understand how to formulate a ...
Unit 3: Bonding and Nomenclature Content Outline: Chemical
... 1. Potential Energy (PE) per atom decreases in a bond. More stable atoms mean less potential Energy per molecule. 2. Molecules release energy when a bond is created; and to break apart molecules require energy input. D. There exists three types of chemical bonds: 1. Covalent Bonds a. The atoms valen ...
... 1. Potential Energy (PE) per atom decreases in a bond. More stable atoms mean less potential Energy per molecule. 2. Molecules release energy when a bond is created; and to break apart molecules require energy input. D. There exists three types of chemical bonds: 1. Covalent Bonds a. The atoms valen ...
February Homework Packet
... be found on the periodic table The atomic number is the number of protons in an atom and the atomic mass is the weighted average of the masses of the isotopes (atomic mass also equals the number protons plus the number of neutrons). Isotopes are atoms of the same element that have different numb ...
... be found on the periodic table The atomic number is the number of protons in an atom and the atomic mass is the weighted average of the masses of the isotopes (atomic mass also equals the number protons plus the number of neutrons). Isotopes are atoms of the same element that have different numb ...
IB Definitions
... Nanotechnology involves research and technology development at the 1 nm - to - 100 nm range. Nanotechnology creates and uses structures that have novel properties because of their small size. Nanotechnology builds on the ability to control or manipulate at the atomic scale.” Food chemistry Define th ...
... Nanotechnology involves research and technology development at the 1 nm - to - 100 nm range. Nanotechnology creates and uses structures that have novel properties because of their small size. Nanotechnology builds on the ability to control or manipulate at the atomic scale.” Food chemistry Define th ...
How to Make a Collage
... The number, three hundred and fifty thousand, written in scientific notation is best written as a) ...
... The number, three hundred and fifty thousand, written in scientific notation is best written as a) ...
Chapter 3
... h is called Planck’s constant: 6.63×10−34 J∙s The idea that energy is quantized rather than continuous is like walking up a staircase or playing the piano You cannot step or play anywhere (continuous), you can only step on a stair or play on a key (quantized). ...
... h is called Planck’s constant: 6.63×10−34 J∙s The idea that energy is quantized rather than continuous is like walking up a staircase or playing the piano You cannot step or play anywhere (continuous), you can only step on a stair or play on a key (quantized). ...
Test 4 Review
... Covalent Bonds. Covalent bonds are bonds formed by sharing electrons. The electrons of one atom are attracted to the protons of another, but neither atom pulls strongly enough to remove an electron from the other. Covalent bonds form when the electronegativity difference between the elements is less ...
... Covalent Bonds. Covalent bonds are bonds formed by sharing electrons. The electrons of one atom are attracted to the protons of another, but neither atom pulls strongly enough to remove an electron from the other. Covalent bonds form when the electronegativity difference between the elements is less ...
X-ray photoelectron spectroscopy
X-ray photoelectron spectroscopy (XPS) is a surface-sensitive quantitative spectroscopic technique that measures the elemental composition at the parts per thousand range, empirical formula, chemical state and electronic state of the elements that exist within a material. XPS spectra are obtained by irradiating a material with a beam of X-rays while simultaneously measuring the kinetic energy and number of electrons that escape from the top 0 to 10 nm of the material being analyzed. XPS requires high vacuum (P ~ 10−8 millibar) or ultra-high vacuum (UHV; P < 10−9 millibar) conditions, although a current area of development is ambient-pressure XPS, in which samples are analyzed at pressures of a few tens of millibar.XPS is a surface chemical analysis technique that can be used to analyze the surface chemistry of a material in its as-received state, or after some treatment, for example: fracturing, cutting or scraping in air or UHV to expose the bulk chemistry, ion beam etching to clean off some or all of the surface contamination (with mild ion etching) or to intentionally expose deeper layers of the sample (with more extensive ion etching) in depth-profiling XPS, exposure to heat to study the changes due to heating, exposure to reactive gases or solutions, exposure to ion beam implant, exposure to ultraviolet light.XPS is also known as ESCA (Electron Spectroscopy for Chemical Analysis), an abbreviation introduced by Kai Siegbahn's research group to emphasize the chemical (rather than merely elemental) information that the technique provides.In principle XPS detects all elements. In practice, using typical laboratory-scale X-ray sources, XPS detects all elements with an atomic number (Z) of 3 (lithium) and above. It cannot easily detect hydrogen (Z = 1) or helium (Z = 2).Detection limits for most of the elements (on a modern instrument) are in the parts per thousand range. Detection limits of parts per million (ppm) are possible, but require special conditions: concentration at top surface or very long collection time (overnight).XPS is routinely used to analyze inorganic compounds, metal alloys, semiconductors, polymers, elements, catalysts, glasses, ceramics, paints, papers, inks, woods, plant parts, make-up, teeth, bones, medical implants, bio-materials, viscous oils, glues, ion-modified materials and many others.XPS is less routinely used to analyze the hydrated forms of some of the above materials by freezing the samples in their hydrated state in an ultra pure environment, and allowing or causing multilayers of ice to sublime away prior to analysis. Such hydrated XPS analysis allows hydrated sample structures, which may be different from vacuum-dehydrated sample structures, to be studied in their more relevant as-used hydrated structure. Many bio-materials such as hydrogels are examples of such samples.