All sections Flashcards
Describe safety hazard symbols.
Indicates a degree and the type of hazard shown by a symbol inside the border.
Degrees
yellow triangle: caution
orange diamond: warning
red octagon: danger
What is WHMIS?
* review the symbols
Workplace hazardous materials information system; they’re warning symbols of hazardous materials.
What is MSDS?
Material Safety data Sheet; identifies the chemical and physical hazards associated with each substance. it includes physical data, such as melting point and boiling point, toxicity, health effects, first aid, and spill/leak cleanup procedures.
What are physical properties? Name 10 of them.
Physical properties describe the physical appearance and composition of a substance.
Examples: boiling/condensation point, melting/freezing point, malleability, ductility, colour, state, solubility, crystal formation, conductivity, magnetism
What is malleability?
The ability to be beaten or rolled into sheets without crumbling.
What is ductility?
The ability to be stretched without breaking.
What is solubility? Crystal formation? What about conductivity?
Solubility is the ability to dissolve. Crystal formation refers to crystalline appearance. Conductivity is the ability to conduct heat or electricity.
What is a chemical property? Name 7.
They describe the reactivity of a substance.
Examples: ability to burn, flash point, behaviour in air, reaction with water, reaction with acids, reaction with acids, reaction heat, reaction to red/blue litmus.
What is flash point?
The temperature needed to ignite a flame.
What is a pure substance?
All the particles that make up the substance are identical; it cannot be broken down into other substances and is made up of one type of atom. It may be an element or a compound.
What is a mixture?
A combination of pure substances; includes mechanical mixtures, suspensions, colloids, and solutions.
What is a mechanical mixture?
Mixture in which the different substances are visible.
What is a heterogeneous mixture?
Mixture in which the different substances are visible.
What is a suspension?
It is a kind of mechanical mixture where the components are in different states. E.g. mud is a suspension of dirt in water.
What is a colloid?
It is similar to a suspension but the suspended substance cannot be easily separated from the other substance.
What is a solution?
One substance is dissolved in another.
What is homogenous mixture?
The separate components are not visible.
What is a chemical reaction?
It is a process that occurs when a substance(s) react to create a different substance or substances. They always involve the production of new substances with their own physical and chemical properties. Energy is always absorbed or released.
Name 3 characteristics of a chemical reaction.
1) all reactions involve reactions involve the production of new substances with their own characteristics
2) all reactions involve a flow of energy (may be detected by a temp change)
3) many cause a phase change like the formation of a gas or a solid precipitate
Bonus: must be consistent with the law of conservation of mass.
Describe a physical change.
- chemical components remain the same
- no new substances form
- e.g. freezing
What is sterilization?
It is any process that kills micro-organisms.
Describe heating and freezing. Are they a physical or chemical change?
Heating food (physically) temporarily sterilizes it. canning involves heat sterilization. Freezing is another physical process that can preserve food; the very low temperature prevents the growth of micro=organisms
What is salting? Is it a physical or chemical change?
Salting is a physical method of preventing meat and fish and is a method of drying. The salt draws the water out of the meat.
What is fermentation? Is it a physical or chemical change? Make sure to mention lactobacilli and lactic acid.
Fermentation is a process in which chemical change occurs. It’s a preservation technique involving the bacteria called lactobacilli, which are present on the surfaces of all living things. They convert starches/sugars present in fruits and veggies into a chemical called lactic acid, which is a preservative that prevents the growth of bacteria that makes food rot.
Extra: lactobacilli make food more digestible and increase vitamin levels.
How does smoking preserve food?
Smoking introduces chemicals called antioxidants that slow the rotting process.
What is metallurgy?
The science of producing and using metals.
What practical advantages does copper have over gold?
Although gold is easier to work with, copper is harder, so it can be made into tools and weapons, as well as jewelry.
What is annealing?
It is the heating of copper before it is hammered. It made the copper easier to hammer because it was no longer brittle.
What is smelting?
It is the process of separating a metal from the other elements in a compound my melting
What is an alloy?
Any mixture of metals. E.g. copper and tin form an alloy called bronze.
What was Aristotle’s description of matter? Was it correct? What about Democritus?
Aristotle believed that all matter was composed of fire, earth, water, and air. He was incorrect. Democritus proposed that matter was made up of tiny particles that could not be divided into smaller pieces. He called them atomos (means indivisible). His theory was much closer to today’s model, but Aristotle was well-respected and his idea was accepted for the next 2000 years.
What is alchemy?
Alchemy was a combination of science and magic, with the goal of turning cheap metals into gold. Scientists wanted to get rich quick, so they were secretive about their work, meaning that specific knowledge was slow to develop.
What did alchemy contribute to the development of chemistry and science?
- mercury was discovered
- procedures for making mineral acids (like hydrochloric acid) were developed
- improved lab equipment
- helped develop casts
What atomic model did John Dalton create? Name four points that he used to explain matter.
Billiard ball model
- all matter is made of small, indivisible particles called atoms
- all the atoms of an element are identical in properties, such as size and mass
- atoms of different elements have different properties
- atoms of different elements can combine in specific fixed ratios to form new substances
What atomic model did J.J. Thomson create? Explain some of his discoveries.
Raisin bun/plum pudding model
- Thomson discovered the electron (negatively charged)
- atoms of different elements contained smaller particles that were identical called subatomic particles
What atomic model did Ernest Rutherford create? Explain some of his discoveries.
Planetary/nuclear model
- discovered the nucleus of the atom
- suggested that an atom is mainly empty space through which the positive particles could pass, but each atom has a tiny, dense, positively charged core
Explain Rutherford’s gold foil experiment.
He shot positively charged particles of a radioactive substance at a thin sheet of gold foil. He predicted that they would pass straight through the foil, which happened to most of the particles. However, some bounced back and some were sharply deflected.
What atomic model did Neils Bohr create? What were some of his discoveries?
Bohr model
- proposed that electrons surrounded the nucleus in specific energy levels
- electrons do not fall below the lowest energy level (never merge with the positively charged nucleus)
Describe the quantum mechanical model of the atom.
- each electron is thought of as a cloud of negative charge, instead of a tiny negative particle
- electrons occupy the whole space all at once at different energy levels
- cloud surrounds a nucleus containing two types of particles called nucleons: protons and neutrons
What are nucleons and their charges?
Protons: positive electrical charge
Neutrons: no electrical charge
Describe metals.
- most are silver/grey
- shiny
- good conductors
- malleable and ductile
- most are solids at room temperature
- some are highly reactive, some are inert expect with the most corrosive acids
What does inert mean?
Unreactice/inactive
Describe non-metals.
- 17 non metals
- can be any state at room temp
- variation in colour
- dull
- usually good insulators
- some are highly reactive and some are generally unreactive, like noble gases
- half exist as molecules
- brittle
Describe metalloids.
- properties of metals and non metals
- some conduct electricity, but not very well
- often brittle solids
What is the periodic table?
It organizes all the elements according to their chemical properties. Metals are on the left side/centre, non-metals on the right, and metalloids in between
What is a period on the periodic table?
A horizontal row, numbered 1 to 7. Usually, the period an element is in determines their number of electron levels.
What is a group/family of the periodic table? What are groups 1 and 2? What about 17 and 18? Describe each of them.
Each vertical column, numbered 1 to 18. Chemical families are groups of elements that have similar chemical/physical properties. Group 1 is called the alkali metals, which are soft, shiny, silver, and very reactive with water. Group 2 is the alkaline-earth metals. They are shiny/sliver but not as soft as group 1. Group 18 is the noble gases, which are very unreactive. The elements in group 17 are halogens, which are poisonous and form salts with group 1.
What accounts for most of the mass of the atom? What about the volume?
Protons and neutrons take up most of the mass. Electrons take up most of the volume.
