Chemistry Flashcards
What does WHMIS stand for? What is WHMIS used for?
Workplace Hazardous Material Information System
~used for workplace/school environments and labs
~eight WHMIS symbols
What does HHPS stand for? Where is it used/found?
Hazardous Household Information Symbol
~Found in household products
~Four main HHPS symbols with three warning levels
What is a physical property?
Describes a substance without changing it chemically
What are the two groups physical properties are divided into?
Qualitative:described using your senses
Quantitative: properties that can be measured
What is a characteristic physical property? What are the 3 characteristic physical properties?
Physical properties that are unique to a substance, meaning no other substance has the same physical property
- density
- boiling/melting point
- mass
What is a chemical property? What are the three chemical properties?
Describe a substance as it is chemically changed into one or more new substances
-combustibility: measure of how easily a substance sets on fire
Ex: paint, fuel oil, magnesium
- light sensitivity: the reaction of a a substance exposed to light ex: hydrogen peroxide is kept in an opaque bottle because it reacts with light
- reaction to acid: the result of adding acid to a substance ex: copper turns green when exposed to acid
What is density? Boiling/melting point? Mass?
Density: ratio of it’s mass to it’s volume. The units are g/mL for liquid and g/cm3 for solid
Boiling point/melting point: the temperature at which a substance boils or melts ex: 0 degrees Celsius is the freezing point of water
Mass: the measure of the wight of a substance
What are the 8 qualitative physical properties? Explain each.
Lustre: shininess or dullness (how shiny a substance is) ex: silver has high lustre and rusty nail has low lustre
Optical clarity: to allow light to pass through; thin blue glass is transparent, frosted glass is translucent and a brick wall is opaque
Brittleness: break ability (how easily a substance breaks) ex: glass is brittle
Viscosity: the ability of a substance to flow or pour readily ex: molasses is viscous and water is less viscous
Hardness: the ability to scratch or be scratched by another substance ex: diamonds is high on the hardness scale and wax is low
Malleability: how flexible a substance is
Ductility: ability of a substance to be pulled into finer strands ex: pieces of copper
Electrical conductivity: ability of a substance to allow an electrical current to pass through ex: copper wires have high conductivity, plastics do not have any conductivity
What is a physical change? Give examples
- Change in the shape or form of a substance
- Doesn’t change what the original substance is
- can usually be reversed
- no new substance is formed
Ex: dissolving, breaking into smaller pieces…
Ex: sugar in water, cutting wood
What is a chemical change? Give examples
Change in the original substance as it reacts chemically with another substance
Ex: corrosion-chemical reaction between metal and oxygen
Ex: combustion-chemical reaction between a substance and oxygen that releases energy
What are the 5 clues a chemical change has occurred? Give examples of each.
- Change in odour
- garbage
- Change in colour
- eggs (clear to white after cooking)
- Gives off heat or light
- Glow stick or firefly
- Forms a precipitate
- milk and vinegar
- Bubbles or fizzes
- vinegar and baking soda
What is volume? Matter?
Volume: how much spaces etching takes up.
Matter: anything that has mass and takes up space
What is the formula for density? What is density, mass and volume measured in?
D=M\V
Mass: grams (g)
Volume: cm or cm^3
Density: g/cm^3 for solid and g/mL for liquid
What is the periodic table? What is it arranged by?
What does the horizontal and vertical axis tell you?
What is ion charge?
How do you find the number of neutrons?
The periodic table is a table of all the elements arranged in order by increasing atomic number
The horizontal axis is the period and it tells you the number of shells there are in that element
The vertical axis is the group/family and it tells you the number of valence electrons
An ion charge tells you the charge number it’ll have if it were to bond with other elements to have a full valence shell. The ion charge number depends on how many it’ll have to lose or gain to have a full valence shell
Subtract atomic number from atomic mass. AM-AN= # of neutrons
What are atoms? What are the 3 subatomic particles location and charge?
Atoms are the main building block of all matter. Made up of three subatomic particles:
Electrons: orbit around nucleus and is negatively charged
Protons: in the nucleus of atom and is positively charged
Neutron: in the nucleus of atom and has no charge
What are elements? Examples?
Element is a pure substance that cannot be broken down into a simpler substance. Consists of only one type of atom
Ex: Hydrogen, Oxygen, Neon (all elements on the periodic table
What are molecules?
Two or more of the same or different atoms chemically joined together
Ex: H2, H2O
What is a particle?
Can be a single atom or molecule
Ex: Hydrogen (H), H2, H2O, HO3
What is a pure substance?
Substance made up of only ONE TYPE of particle; the particles are chemically joined together
Pure substances are elements, compounds, particles, molecules
Ex: H2O, H2, H2SO4, Fe
What is a mixture?
Substance made up of at least two DIFFERENT types of particles
Ex: H2O&H2SO4
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The “&“indicates that H2O and H2SO4 are not chemically combined but just mixed together
What is a compound?
Pure substance composed of two or more DIFFERENT elements joined together
Ex: H2OH, H2O
All compounds are molecules but not all molecules are compounds. This is because compounds are two or more DIFFERENT elements joined together (ex: H2O, H2SO4) and molecules are two or more SAME or DIFFERENT atoms joined together. So, compounds can be molecules but not all molecules are compounds. The molecules that are made of the same atoms cannot be compounds.
What is a subscript?
Small number in front of element symbols indicating how many atoms there are
Ex: H2O
-2 hydrogen atoms and 1 Oxygen
Ex: (H2O)3
Six hydrogen atoms and three oxygen
What is a coefficient?
Total number of molecules present
Ex: 3H2O =H2O + H2O + H2O
Three H2O molecules
To count how many elements there are in a molecule, multiply all the elements to the coefficient
In this case, there are 6 hydrogen atoms and 3 oxygen
What are metals, non-metals and metalloids and where are they on the periodic table?
Metals: good conductors of heat and electricity and are malleable. They are on the left side of the periodic table
Metalloids: have properties both of metals and non-metals. In their physical properties, they a more like non-metals, but under certain circumstances, several can be made to conduct electricity. Along the staircase between metals and non-metals, separating the two.
Non-metals. Are usually poor conductors of heat and electricity and are not malleable or ductile. Many non-metals are solids, liquids or gas at room temperature
What are the 5 trends in the periodic table?
- Valence electrons
- number of electrons in the outer most shell is the same for all the elements in the same group/family - Electron shell
- the number of electron shells is the same for all the elements in the same period - Reactivity
- the reactivity of an element increases as you go down a group - Atomic radius
- the distance from the centre of nucleus to the boundary of surrounding cloud of electrons (first shell) - Atomic mass
- the atomic mass of an element increases as you travel down a family/group
What are the group 1 elements? Group 2? Group 17? Group 18?
Group 1 elements are alkali metals. They are very reactive because they only have 1 valence electrons, so they can easily lose this to get a full valence shell
Group 2 elements are alkaline-earth metals. They are not as reactive as group 1 elements but still fairly reactive because they need to lose two electrons to have full valence shell
Group 17 elements are halogens and they are the most reactive elements in the periodic table because they have 7 valence electrons, so they can easily gain one to fill valence shell.
Group 18 elements are noble gases and they have full valence shell, so they are the least reactive elements.
Hydrogen has only 1 electron so it can either lose one or gain electrons. Very unreactive element
The reactivity of electrons in the outer-most shell increases as you travel __________ a ___________
Travel; group
The reactivity of an element depends on the ____________________________ it has.
Number of valence electrons
The number of electron shells increase as you travel down a _____________________
Period