The candle was described qualitatively and quantitatively before it was lit, during burning and after burning.
Ice cubes were placed in a beaker. Observations were made and recorded. The height of the water in the beaker was measured before melting and after melting. The height did not change because the ice displaced the water and when it melted it filled the space up.
Buttons and "wild things" were classified as a binary classification system and a multi-stage classification system.
Why does moisture collect on a beaker of ice water? Because room temperature is warmer than the ice water and causes condensation. The condensation comes from the moisture in the air. We can show that the moisture does not come from inside the glass by adding food coloring to the water.
The warmer water dissolved the Alka-Seltzer tablet faster than cooler water. The manipulated variable was the water temp., the responding variable was the time it took for the tablet to dissolve, and the control variables were the size of the tablet, the brand of the tablet, the water, the plastic cups, and the amount of water.
What's in a bag of M&M's? Predict the number of M&M's in a bag, the number of each color, and the most and least common colors. Compare data with the rest of the class groups and chart the data. On average there were more orange M&M's and the least amount were the red M&M's.
Tanagrams - one group member secretly made a design and tried to guide the other group members only with words on how to create the design. Not easy.
The stuff that everything is made of, or anything that has mass and volume
The amount of matter in an object, expressed in grams
The measure of the force exerted on an object by the pull of the Earth's gravity, expressed in Newtons
the amount of space taken up by an object, defined by l x w x h, or mL
constant composition with a specific set of properties
basic building blocks of matter
2 or more elements
2 or more pure substances where each substance will keep its own identity, does not form a new substance. i.e. sweet tea
Difference between physical and chemical properties and change:
Physical Properties - characteristics of an object that can be observed or measured, can be changed without changing the object itself
Chemical Properties - chemical changes the ability of matter to change into a new substance that has different properties. i.e. sterling silver -> (oxidation) -> black color (petina)
4 Signs that can tell you a Chemical Change has taken place:
1. gas is produced - fizzing
2. color change - rust
3. temperature change
4. produces light
Difference between heterogeneous and homogeneous mixtures:
Homogeneous mixture - well mixed, appears to be uniform but proportions can vary. i.e. sugar in a glass of tea
Heterogeneous mixture - not uniform, unevenly mixed
3 Phases of Matter and difference in physical properties of each:
Liquid - definite volume and indefinite shape
Solid - definite volume and definite shape
Gas - indefinite volume and indefinite shape
Burning a Candle Activity
The wick and wax work together as a system. The wax is the fuel and the wick transports the fuel to the flame. Without oxygen the flame cannot burn.
The Distinguishing Properties of Common White Powders
Each substance (granulate sugar, table salt, baking soda & cornstarch) behave differently when mixed with the various substances (water, iodine & vinegar). The biggest reaction came from mixing iodine with cornstarch. The cornstarch hardened and turned black. the other came when mixing vinegar and baking soda, which produces a gas evident from fizzing. Both of these are chemical reactions.
What are the properties of Oobleck?
Liquid or Solid? It doesn't have a definite shape, so it can't be a solid. It has a definite volume and no definite shape so it fits the definition of a liquid.
Changes of State of Water - 6 changes
+ Heat NRG
Solid -> Liquid = Melting
Liquid -> Gas = Evaporation
Solid -> Gas = Sublimation
- Heat NRG
Gas -> Liquid = Condensation
Liquid -> Solid = Freezing
Gas -> Solid = Deposition
The energy absorbed or released during a change of state.
the amount of heat it take to raise 1 gram of water 1 degree Celsius
Dew point temperature
the temperature at which the air must be cooled in order for condensation to occur
change of state from a gas to a liquid with a loss of heat energy
description of the amount of water vapor in the air
the maximum possible amount of water vapor the air can hold at a given temperature and pressure
in a graduated cylinder the meniscus is read at the bottom of the curve
What is condensation and how does it occur?
Condensation is a change of state when a gas turns into a liquid with a loss of heat energy. The ice cools the sides of the cup which cools the warmer air that contains the water vapor very close to the outside of the cup. Water vapor gathers on the outside of the cup as condensation.
What is the temperature at which condensation takes place?
Condensation first started showing on the cup at 5 degrees Celsius, when the temperature had dropped 19 degrees.
3 Subatomic Particles
Proton - inside nucleus, + charge, atomic #, identification of element depends on the number of protons
Electron - outside nucleus, - charge, # always = # protons, influence chemical reaction
Neutron - inside nucleus, no charge
the order of an element in Mendeleyev's table of the elements; equal to the number of protons in the nucleus
Atomic Mass Number (Atomic Weight)
Protons + Neutron = Atomic Mass
2 or more atoms are combined, smallest unit of a compound
Organization of the Periodic Table - Names of Groups
Rows: periods, there are 7
Columns: family - there are 18, they react in the same way
Group 1: Alkali Metal - very reactive, hardly find in nature
Group 2: Alkaline Earth Metals
Group 3 - 12: Transition Elements
Group 13 - 16: BCNO
Group 17: Halogens - non-metals, 5 elements, combine with alkali metals for form salts
Group 18: Noble Gases - found in Earth's atmosphere, colorless and odorless
Red Symbols: Gases
Solid Black Symbols: Solids
Blue Symbols: liquids at room temperature
Difference between a metal, nonmetal and metalloid:
Metal (left hand side):
Silver gray in color
Shiny metallic luster
Can be magnetic
Good conductors of heat and electricity
Non-Metals (right hand side):Not shiny
Brittle - will shatter
Not conductors of heat or electricity
Some gases at room temp., some liquids & some solids
Metalloid (semi-conductors in red outline):
Dull or shiny
Malleable or brittle
Conduct heat and electricity better than non-metals but not as good as metals
Has properties of metal and non-metals
Which 2 elements are liquids at room temperature?
Bromine and mercury
an attractive force that holds atoms together in a compound
Spheres of Hydration
The sphere of water molecules around each dissolved ion.
attraction of like molecules
attraction of dissimilar molecules
a change in matter in which different chemical substances are created by breaking or forming chemical bonds
Water-loving, readily bonds with water
does not like water, i.e. oil
chemical reaction occurring or formed with absorption of heat
chemical reaction occurring or formed with the release of heat
4 Types of Chemical Bonds
Covalent - formed by sharing a pair of electrons, generally, non-metallic elements
Polar - unequal sharing
Non-polar - atoms share electrons equally
Ionic - atoms transfer electrons, in general a metal reacts with 1 or more nonmetals
Metallic - formed between 2 or more metals, give electrical conductivity
Hydrogen - atoms share electrons in a water molecule
Unusual Properties of Water
1. The only substance found naturally on Earth in all 3 states
2. Temperature scales all based on water
3. Universal solvent
6. Polarity of water - water attracts other polar molecules like sugar which is hydrophilic
Balance Chemical Equations
Law of Conservation of Mass
Matter is neither created nor destroyed during a chemical reaction
Oxidation-Reduction Reaction - Redox
An oxidizing chemical change where an element's electron loss is accompanied by a simultaneous electron gain.
Generalized form for Each of the Subclasses or Redox Reactions
1. Combination reaction: x + y -> xy
2. Decomposition reaction: xy -> x + y
3. Replacement reaction: xy + z -> xz + y
Chemical Heating Activity
The vinegar reacted with the steel wool and produced heat energy. Evidence of a chemical reaction: produced rust, heat, and moisture
Change hydrogen peroxide into water and oxygen with the aid of a potato
Tiny bubbles form and rise to the top
The potato releases oxygen to form bubbles
Decomposition Reaction: H2O2 >> 2H2O(l) + O2 (g)The potato contains enzymes catalase that speeds up the reaction.
Mix yeast with hydrogen peroxide. The yeast reacted to the hydrogen peroxide and heat energy was released raising the temperature of the mixture. Evidence of a chemical reaction: heat is produced, bubbles produced
The Epsom salt absorbed the water's natural heat energy to split apart the magnesium and sulphate therefore making the water cooler.
MgSO4 + H2O
Bill Nye - Chemical Reactions
Everything is mad of chemicals
Chemicals react to make new chemicals
Electrons hook together
Chemicals react with chemicals in the air and give off heat
Water is the most important chemical
92 pure elements
Alfred Nobel - Swedish chemist who invented dynamite