Unit A Energy and Matter in Chemical Change : 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?
To protect the environment and the people
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 the 3 types of heterogeneous mixtures?
- Mechanical mixtures
- Suspensions
- Colloids
What is one type of homogenous mixture?
Solution
What are the 4 types of mixtures?
- Solutions
- Mechanical mixtures
- Suspensions
- Colloids
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 caused scurvy?
The lack of vitamin C
What did sea captains do to get rid of scurvy?
They brought pickled cabbage aka Sauerkraut
Scurvy is caused by a severe lack of vitamin C (acetic acid). At sea it is hard to get fresh produce so they realized that they would need to have something preserved but that still contains vitamin C. Fermenting actually increases the likelihood of absorbing vitamins and helps digestion along with preserving the food so that it doesn’t rot.
What is metallurgy?
The science of producing and using metals
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
Who were the 4 scientists who contributed to models of atoms?
- Dalton
- Thomson
- Rutherford
- Bohr
Who created the Billiard ball model?
John Dalton
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
What are the physical characteristics of metals?
- Silver or grey
- Shiny
- Malleable and ductile
- Solid
Which metal is not solid at room temperature?
Mercury
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
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
What are groups in the periodic table that react to form salts?
Halogens and Alkali Metals
Halogens can also combine with other metals to form salts.
Salts are formed from an acid and an alkali.
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 and neutrons
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 in 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 isotope of an element be described by?
Nuclear notation which includes the following:
Mass Number top left
Element Symbol right
Atomic Number bottom left
What is the atomic molar mass?
The average mass of a mole of an element’s 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 ionic compounds? What are the physical properties of ionic compounds?
- Solid
- High melting and boiling points
- Conductive
- Retention of crystal shape
- Soluble in water
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
Nona
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?
Chlorofluorocarbons (CFCs) are non-toxic, nonflammable chemicals containing atoms of carbon, chlorine, and fluorine. They act as catalysts in the upper atmosphere and cause destruction of the Earth’s 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 chemicals like carbon monoxide, carbon dioxide, tar, formaldehyde, and benzene. It also damages the respiratory or circulatory systems
