FLAME TEST AND CHEMICAL AND PHYSICAL TEST Flashcards
study of matter and the changes it undergoes
Chemistry
Chemistry is the study of matter and the changes it undergoes. These changes can be broken down into two classes
Physical Change and Chemical change
Grinding, melting, dissolving, and evaporating all are all what kind of change
Physical Change
change results in the formation of one or more “new” substances. These new substances differ in chemical properties and composition from the original substance
Chemical Change
The rusting of iron and the burning of paper are two examples of
Chemical Change
an insoluble solid that emerges from a liquid solution
Precipitate
The emergence of the insoluble solid from solution is called
Precipitation
Often the precipitate emerges as a
Suspension
this can form when two soluble salts react in solution to form one or more insoluble products
Precipitates
can also form insoluble solid when the temperature of a solution is lowered
precipitate
reduce the solubility of salts, which may result in their precipitation as solids
Lower Temperature
the formation of gas bubbles in a liquid by a chemical reaction
Effervescence
the release of carbon dioxide which bubbles as a gas from the liquid when limestone chips, which are composed of calcium carbonate, are added to dilute hydrochloric acid. It is an example of
Effervescence
process resulting from random motion of molecules by which there is a net flow of matter from a region of high concentration to a region of low concentration
Diffusion
meaning that this is completely saturated with carbon dioxide (CO2). Thus, the fizz is not effervescence, not a chemical change.
Carbonated drinks, such as soda, are in a state of supersaturation
theorized that electrons have specific energy values
Bohr
Bohr theorized that electrons have specific energy values, which he called
Energy levels
meaning that only specific energy levels were possible around the nucleus of an atom
Quantized
can absorb energy and undergo a transition to a higher energy level
electron in a low energy level
True or False: Electrons move between energy levels by gaining or losing a specific amounts of energy. When this occurs, we say that the electron undergoes a transition from one energy level to another.
True
When that electron returns to the ground state, what will happen
it loses energy by emitting a photon
which is a tiny particle that behaves like a wave and travels at the speed of light
photon
a procedure used to test qualitatively for the presence of certain metals in chemical compounds
flame test
the presence of a potassium ion in a compound will color a flame
violet
sodium ions in a compound produce a very strong what color flame
yellow
the range of frequencies of electromagnetic radiation and their respective wavelengths and photon energies
Electromagnetic Spectrum
7 types of electronic radiation
- Radio Waves
- Microwave
- Infrared Radiation
- Visible Light
- Ultraviolet Radiation
- X-ray
- Gamma Ray
a particular type of electromagnetic radiation that can be seen and sensed by the human eye, but this energy exists at a wide range of wavelengths
Light
the basic unit for measuring the wavelength of electromagnetic waves
Micron
The shortest waves which have wavelengths of 10e-6 microns or less
Gamma Rays
The longest waves which have wavelengths of many kilometers
Radio Waves
The range of visible consists of the narrow portion of the spectrum, from
0.4 microns (blue) to 0.7 microns (red)
the portion of the electromagnetic spectrum that is visible to the human eye
Visible Spectrum
The visible spectrum is the portion of the electromagnetic spectrum that is visible to the human eye. Electromagnetic radiation in this range of wavelengths is called
visible light or simply light
A typical human eye will respond to wavelengths from about
380 to 740 nanometers
Give the color: 400-430 nm
Violet
Give the color: 430-490 nm
Blue
Give the color: 490-560 nm
Green
Give the color:
Give the color: 560-580 nm
Yellow
Give the color: 580-620 nm
Orange
Give the color: 620-800 nm
Red
a term meaning to “carry along gently as through the air”
Waft
The term is commonly used to describe scents that have diffused into other parts of a room, or to describe smoke as being seen moving through the air
Waft
Wafting may be used for everyday substances, to make sure they are
fresh, or consumable
pass or cause to pass easily or gently through or as if through the air
Waft
protein obtained by boiling skin, tendons, ligaments, and/or bones with water. It is usually obtained from cows or pigs
Gelatin
gases which stays lightly over water are called
wafting gas
These gases are harmful for people leaving in coastal areas. They are mainly released from industries and cause breathlessness; They are often colourless with pungent smell
Wafting gas
When you are in the laboratory and take a direct sniff of the chemicals you are using, you run the risk of damaging your, what part
mucous membranes or your lungs
an odor in a laboratory is best done using the technique of
Wafting
involves drawing one’s hand across the opening of a container in order to push the odor towards the nose
Wafting
quickly diffuse through air
Most gases, including noxious ones
The lower the molecular weight of the gas, the faster its rate of what
Diffusion
An increase in temperature will also increase the rate of
Gas Diffusion
Gel air fresheners are able to scent the air for a long time because gelatin is a
polymer
collagen, a protein that forms a matrix type structure, allowing the gelatin to hold its shape
polymer
suspended in the matrix of the gel which keeps the scent trapped inside
fragrance oil particles
what will happen if the gel evaporates
the scent particles are released from the matrix, causing a continuous scent to be released from the air freshener
The chemical reaction in burning natural gas is the reaction of methane (CH4) with oxygen (O2) in the air. If excess oxygen is used, the products would be gaseous carbon dioxide (CO2) and gaseous water (H2O)
Complete Combustion
If insufficient oxygen is available, we would have an incomplete combustion, producing
poisonous carbon monoxide (CO) and soot (C)
Insufficient oxygen would also result in a cooler, yellow flame, called a
luminous flame
due to small particles of soot being burned to incandescence
Yellow color
what are we going to do if we need a hotter flame
we would need to introduce more oxygen, by mixing
more air with the methane gas before combustion
the hotter the flame what color it represents
blue
what is the hottest part of the flame
the tip of the inner blue cone of the flame
controls how much natural gas (methane) is piped to the Bunsen
burner. When the handle is pointed straight at you, the valve is fully opened. You close the valve by turning the handle either left or right. The gas goes to the Gas Inlet through a piece of rubber tubing.
The Gas Valve
at the bottom of the burner controls how much methane goes
from the Gas Inlet into the Barrel
The Needle Valve
control how much oxygen from the air is mixed with the methane. You adjust it by holding the Barrel (before it gets hot) and turning it either direction, to open or close the air vents. If you want a very hot flame, you would open this parts to allow a maximum amount of oxygen to mix with the methane. You might have to also use the Needle Valve to allow less methane in so that there is a higher ratio of O2 to CH4.
The Air Vents
colourless, odourless gas that occurs abundantly in nature and as a product of certain human activities. This is the simplest member of the paraffin series of hydrocarbons and is among the most potent of the greenhouse gases. Its chemical formula is CH4.
Methane
a chemical process in which a substance reacts rapidly with oxygen and gives off heat. The original substance is called the fuel, and the source of oxygen is called the oxidizer. The fuel can be a solid, liquid, or gas, although for airplane propulsion the fuel is usually a liquid.
Combustion
the emission of electromagnetic radiation (including visible light) from a hot body as a result of its rising temperature.
Incandescence
unique because the properties of water allow it to exist in all three states of matter
Water
Water is usually a liquid, but when it reaches to what Fahrenheit (F), it freezes into ice.
32°
the solid state of water
Ice
When water reaches what F, it boils. When it begins to boil, some of the water turns into steam
212° F
the gas state of water, and is also called water vapor
Steam
Normally, when water reaches what F it begins to freeze.
32°
it lowers the freezing point of water and is often used to melt dangerous ice off of roads and sidewalks in the winter.
Salt
particles are very close together, so they cannot be squeezed. The
attraction between nearby particles in a solid is usually strong. Because there are such strong bonds between the particles, solids usually have a fixed shape and a constant volume. The particles in solids cannot move freely; instead Particles in a solid they vibrate in a fixed position.
Solid
particles are held together by attraction, but the bonds between them are weaker than those in solids. The particle attraction allows the particles to roll over each other, but they can’t ‘escape’. It have a fixed volume, but the rolling motion of the particles allows them
to take up the shape of their container. As in solids, the particles are still very close together, so it is cannot be Particles in a liquid compressed into smaller spaces
Liquid
spread out and will not stay in a container unless it has a lid. The particles have much more energy than those in solids or liquids, and are constantly moving. The attraction between the particles in this is so weak that they can move freely in all directions. They spread out and take up any space that is available, so this have no fixed shape or
volume. Because of the large spaces between Particles, it can be
compressed.
Gas
composed of different types of atoms or molecules that are not chemically bonded
Mixture
a mixture of two or more chemical substances where the
various components can be visually distinguished
Heterogenous mixture
a type of mixture in which the composition is uniform and
every part of the solution has the same properties
Homogeneous mixture
The scattering of visible light by colloidal particles. You have
undoubtedly “seen” a light beam as it passes through fog, smoke, or a scattering of dust particles suspended in air. All three are examples of colloids. Suspensions may scatter light, but if the number of suspended particles is sufficiently large, the suspension may
simply be opaque, and the light scattering will not occur
Tyndall effect
the process that takes place when a substance (or substances) are brought into contact with each other and produce a new substance(s)
Chemical Reaction
The substance (or substances) initially involved in the chemical reaction are called
reactants or reagents
usually characterized by a chemical change, and they yield
one or more products, which usually have properties different from the reactants
Chemical Reaction
represented by Chemical Equations
Chemical Reaction
balanced to show the same number of atoms of each element on each side
Chemical Equation
states that matter cannot be created nor destroyed. What this means is that even though different substances are created during the process of a chemical reaction, none of the reactant atoms are lost. They are simply rearranged into the new substances
Law of Conservation of Mass
any process which requires or absorbs thermal energy from its surroundings, usually in the form of heat. It may be a chemical process, such as dissolving ammonium nitrate in water, or a physical process, such as the melting of ice cubes
Endothermic
describes a process or reaction that releases energy from the system to its surroundings, usually in the form of heat, but also in a form of light, electricity, or sound.
Exothermic
