Unit A: Exam Flashcards
What does an orange diamond mean?
Warning
What does a red octagon mean?
Danger
What does a yellow triangle mean?
Caution
What shape are WHMIS symbols in?
Circles
What does WHMIS stand for?
Workplace Hazardous Materials Information System
What are MSDS?
Sheets that identify the chemical and physical hazards associate with each substance. It also includes the physical properties
What is the most important safety feature in the lab?
You
Why does the Canadian government have so many rules and regulations for chemicals?
The environment
What do are physical properties?
Properties that describe the physical appearance and composition of a substance
What are some examples of physical properties?
- Boiling point
- Melting point
- Freezing point
- Malleability
- Ductility
- Color
- State
- Solubility
- Crystal formation
- Conductivity
- Magnetism
What is Malleability?
The ability to be beaten or rolled into sheets without crumbling
What is Ductility?
Ability to be stretched without breaking
What is Solubility?
The ability to dissolve
What is Conductivity?
Ability to conduct heat or electricity
What is Magnetism?
Magnetic attraction between objects
What are Chemical Properties?
Properties that describe the reactivity of a substance
What are some examples of chemical properties?
- Ability to burn
- Flash point
- Behavior in air
- Reaction with water
- Reaction with acids
- Reaction to heat
- Reaction to litmus paper
What is Flash Point?
Temperature needed to ignite a flame
What are the 2 groups that matter can be classified into?
Pure substance and mixtures
What is a pure substance?
A pure substance is when all the particles that make it up are identical and cannot be broken down
What can be in a pure substance?
An element or compound
What is a compound?
A chemical combination of two or more elements in a specific ratio
What is a mixture?
A combination of pure substances. The proportions and properties vary
What are the 3 types of heterogeneous mixtures?
- Mechanical mixtures
- Suspensions
- Colloids
What is the one type of homogenous mixture?
Solution
What are the 4 types of mixtures?
- Solutions
- Mechanical mixtures
- Suspensions
- Colloids
What is a mechanical mixture?
A mixture where the different parts are visible such as soil
What is a suspension?
A type of mixture where the components are in different states such as mud
What is a colloid?
A type of mixture where the suspended mixture is in different states but cannot separate out easiliy
What is solution?
When the different parts are not visible and the mixture is uniform throughout
What is a chemical reaction?
A process that occurs when a substance or substances react to create a different substance or substances
What do chemical reactions always produce?
New substances that have completely new properties
What are the characteristics of chemical reactions?
- Involve production of new substance
- Involve the flow of energy
- Cause a phase change
What is a phase change?
-Formation of a gas or solid
What are the ways of food preservation?
- Freezing
- Salting
- Fermentation
What does heating do to food?
Temporarily sterilizes it
What is sterilization?
Any process that kill micro-organisms
What does freezing to food?
Preserves food almost indefinitely
How does freezing preserve food?
The low temperature prevents the growth of micro-organisms that cause decay
What salting do to meat and fish?
Dries and preserves by drawing the water out and kills bacteria
What caused scurvy?
The lack of vitamin C
What did sea captains do to get rid of scurvy?
They brought pickled cabbage aka Sauerkraut
What is fermentation?
A technique using the bacteria lactobacilli that converts starches and sugars into a chemical called lactic acid
What is Lactic Acid?
A preservative that prevents that prevents the growth of bacteria that cause food to rot
How is lactobacilli beneficial to food?
Increases digestion and increase vitamin levels
What is smoking?
A method of food preservation
How does smoking preserve foods?
Introduces anti-oxidants that slow the rotting process
What is metallurgy?
The science of producing and using metals
Why was gold used extensively in jewelry?
Because it is soft and easy to work with
What was copper originally used for?
Weapons and jewelry
What type of copper did the intuit use?
Native copper found in pure form in the Coppermite river
What was the problem with copper?
When it was hammered it became bitter
What is annealing?
Heating of a metal before it is hammered
What solved the copper problem?
Annealing and smelting
What is smelting?
Separating a metal from other elements in a compound by heating
What is bronze?
The product produced when tin and copper are smelted
What is steel?
The product produces when Iron and Carbon are mixed
What did Aristotle believe about matter?
That it was made from fire, earth, water and air
Who was the first to coin the term atoms?
Democratis
What is alchemy?
A combination of science and magic
Why was scientific knowledge slow to develop in alchemy?
Because they were just finding ways to get rich quickly and did not want to share information
What did Robert Boyle do?
Measured relationships between volume and pressure of gasses
Who created the Law of Conservation of Matter?
Antoine Lavoisier
Who were the 4 scientists who contributed to models of atoms?
- Dalton
- Thomson
- Rutherford
- Bohr
Who created the Billiard ball model?
John Dalton
Describe John Daltons model of the atom
- All elements of a certain element are identical
- Atoms of different elements have different properties
- Atoms can combine in fixed rations to form substances
- Small spheres
Who discovered the electron?
J.J. Thomson
How did J.J. Thomson discover the electron?
- He was experimenting with beams of particles in a vacuum.
- It showed that all the beams were negative
- He concluded that they all must have something in common causing them to be negative
What model of the atom did J.J. Thomson create?
The raisin bun model
-He suggested that the sphere was positive and it had negative electrons embedded in it
What did Ernest Rutherford believe about atoms?
An atom is mainly empty space but each atom has a tiny positively charged core
How did Ernest Rutherford come to the conclusion of the nucleus?
- He had a radioactive material that produced positive particles and aimed it at gold foil
- He thought they would go straight through or be slightly deflected but instead some bounced back
- He said that sometimes the positive core was so strong it caused the atom to be very deflected
Who discovered the nucleus?
Rutherford
What did Neils Bohr believe?
Electrons orbited the nucleus in different levels
How did Neils Bohr come to his conclusion?
When electrons fall from different energy levels they emit different light
What is the Quantum Mechanics Model of atoms?
Electrons are thought of as clouds of negative charge that surrounds a nucleus of protons and neutrons
What are reactants?
The substances that react in a chemical reaction
What are products?
The new substances produced in a chemical reaction
How many elements are there?
115
What are the 3 classes of the periodic table?
Metals
Non-metals
Metalloids
What are the physical characteristics of metals?
- Silver or grey
- Shiny
- Malleable and ductile
- Solid
Which metal is not solid at room temperature?
Mercury
What does inert mean?
Unreactive
Why are non-metals grouped together?
For their lack of resemblance to each other
What type of variation is there in non-metals?
State
Color
Reactivity
Which group on the periodic table is the most non-reactive?
Noble gasses
What are molecules?
Groups of non-metallic elements held together by covalent bonds
What are metalloids?
Elements that have properties that are intermediate between metals and non-metals
What properties does the periodic table organize elements?
Chemical
Why is hydrogen special?
It is a non-metal but acts like a metal in chemical reactions
What is a period?
Each horizontal row on the periodic table
What is a group or family?
Each vertical column on the periodic table
What are chemical families?
Groups of elements that have similar chemical and physical properties
What is the very first group in the periodic table called?
Alkali metals
What is the group to the left of the noble gases?
Halogens
Which two groups in the periodic table react to form salts?
Halogens and alkali metals
What is an atom?
The smallest part of the element that still has the properties of the elements
What are the 3 kinds of subatomic particles?
Electrons
Protons
Neutron
What are electrons?
Negatively charged particles
What are protons?
Positively charged particles
What are neutrons?
Neutral particles
What adds most weight in an atom?
Protons
What is an energy level?
A region of space near the nucleus that may be empty or contain electrons
How many electrons can each energy level hold?
2, 8, 8
What does the atomic number indicate?
The number or protons on an atom
What are isotopes?
Atoms of the same element that contain different numbers of neutrons
What is Deuterium?
An isotope of hydrogen that contains 1 proton and neutron
What is the mass number?
Total number of protons and neutrons in the nucleus of an atom
What will the element of an isotope look like?
Mass Number
Element Symbol
Atomic Number
What is the atomic molar mass?
The average mass of an elements isotopes
What is ionization?
The process of gaining or losing an electron
What is an ion?
An electrically charged atom
What are cations?
Positively charged ions
How is a cation formed?
An atom loses an electron and represents with a +
What are anions?
Negatively charged ions
How do anions form?
When atoms gain electrons and represents a -
Why do atoms gain or lose electrons?
So they have the same number of electrons of a noble gas
Why are noble gasses so stable?
They have filled outer energy levels
What are electrons in the outermost energy level called?
Valence electrons
What is the valence number?
The number of electrons an element can gain or lose to combine with other elements
What does the octet rule state?
Atoms bond in such a way as to have 8 electrons in their valence energy level
What is a crystal lattice?
What forms when an ionic compound forms
What state are the physical properties of ionic compounds?
- Solid
- High melting and boiling points
- Conductive
- Retention of crystal shape
What are multivalent elements?
Elements with more than 1 stable element
What is the chemical formula for methane?
CH4
What are the physical properties of molecular compounds?
- Any state
- Poor conductors
- Low boiling and melting points
How do atoms of molecules bond?
Using covalent bonds
What is a covalent bond?
When atoms share electrons so that they exist in both elements at the same time
What are molecular elements?
Molecules made of only type of element
What are prefixes for numbers 1-10
Mono Di Tri Tetra Penta Hexa Hepta Octa Ennea Deca
How can you recognize an ionic compound?
They will always have a positive and negative ion
What does polar mean?
Each water molecule is slightly positive and slightly negative so they attract each other
What is an electrolyte?
Any solution that conducts electricity
What does the subscript aq mean?
Aqueous, dissolved in water
What is a precipitate?
A solid with a low solubility that forms when 2 solutions are mixed
What is special about water?
It is polar because it has a positive and negative end so that they attract each other
Why does ice float?
Because there are fewer molecules of water in the ice because it spreads out
What type of acid is in stomachs?
Hydrochloric acid
What is an acid?
A compound that dissolves to form a solution with a pH lower than 7
What is a base?
A compound that dissolves to form a solution with a pH higher than 7
What is the pH of saliva?
Basic
What does the enzyme pepsin do?
Speeds up the digestion of protein and amino acids
What does the pancreas do?
Produces sodium hydrogen carbonate to deactivate pepsin
What is a buffer?
A substance that can keep the pH of a solution nearly constant despite the addition of an acid or base
What are the properties of acids?
- Sour
- Not slippery
- Reactive with metal
What are the properties of bases?
- Bitter
- Slippery
- Non-reactive with metal
What is a universal indicator?
A mixture of several different indicators that change color as the acidity changes
What is the pH of a neutral substance?
7
How can you identify an acid by its chemical formula?
It will begin with H or end with -COOH and will always be aqueous
How can you identify a base by its formula?
It will always end in OH
What is neutralization?
A reaction between acids and bases that produces water and salt
What are Chlorofluorocarbons?
Chemicals that chlorine that act as catalysts in the upper atmosphere and causes destruction of the earths ozone layer
What are the 2 most commonly used hazardous recreational substances?
Alcohol and nicotine
How does alcohol affect the body?
Cause destruction of the liver, kidneys, and brain cells
What is physical dependence or addiction?
When the body becomes used to the drug and needs it to function
What is psychological dependence?
When the use of a drug is linked to a certain mood or feelings but when the drug wears off the feeling disappears
What is nicotine present in?
All tobacco products
Why are cigarettes dangerous?
Because they contain many chemical like carbon monoxide, tar, formaldehyde, and benzene. It also damages the respiratory or circulatory systems
