Post on 20-Feb-2017
Compounds And Elements
Objectives:3.3 Describe a pure substance as a
compound or an element, after conducting an experiment.
3.4 Analyze a compound.
Classification: Everything in the world that has a mass
is called “matter” Matter can be classified as:
Matter
Pure Substance Mixture
Element Ex. gold
Compound Ex. water
Hetero-geneous Mixture
Homo-geneous Mixture
Matter:anything that takes up space & has a
mass
Ex. a deskEx. pizzaEx. silver necklaceEx. oxygen
Mixture: combinations of two or more substances
that are not chemically combined (mixed)Easily separatedEx. fruit saladEx. sugar in coffee
Pure Substance: composed of a single substance with the
same properties throughoutEx. waterEx. table salt
simplest form of matter
cannot be separated or broken down into simpler substance
Ex. Oxygen Ex. Aluminum Ex. Gold Ex. Copper
A pure substance can be further broken down into an element or a compound……Elements:
substance made of two or more elements
can be separated into simpler substance
Ex. Water (H2O) Ex. Carbon dioxide (CO2) Ex. Sugar (C6H12O6) Ex. Salt (NaCl)
Recall, a pure substance can be further broken down into an element or a compoundCompounds:
NOTE:With chemical reactions you can go from an element to compound & vise versa!!!
Element Compound
HO
Ex. oxygen & hydrogen
Ex. water (H2O)
H
OH H
Recall, a mixture can be further broken down into a homogeneous mixture or a heterogeneous mixture……
Homogeneous Mixture:Mixture that looks uniform throughout or
like one substance
Ex. milk in coffeeEx. sugar dissolved in water
Heterogeneous Mixture:mixtures that are not uniformcan see individual parts
Ex. saladEx. chocolate chip muffin
State whether the following are examples of an
element or a compound.
A gold ringRust (Fe2O3)Carbon monoxide (CO)Aluminum FoilCalcium
element compound
compound element element
State whether the following are examples of an element or a
compound or a mixture
A blueberry muffinChunky SoupSalt (NaCl)Helium Water (H2O)
mixture mixture compound elementcompound
Element Compound Mixture Compound
State whether the following pictures represent an element or a compound or a mixture
Which statement best describes a compound.
A) A pure substance that has a high melting point.
B) A mixture that is formed by two or more elements.C ) A pure substance that is formed by two or more elements.
Reactions:Chemical Reactions can combine
elements to make compounds (synthesis reaction)
OR
Chemical Reactions can break apart compounds into its elements(decomposition reaction)
Synthesis Reaction:
Makes a new substance Sign of a chemical change Increase in mass Ex.
Ex.
If you see mass, the ONLY thing
you know is that a compound was
made!!!
+
+
Decomposition Reaction:
Two or more substances produced Sign of a chemical change Decrease in mass Ex.
Ex.
If you see mass, the
ONLY thing you know is
that you started with
a compound!
+
+
You a leave a 2g copper penny outside. Over time, the penny becomes green in color & its mass is now 2.5g.
Which statements below are true?A) A chemical change occurredB) A physical change occurredC) A compound was made
TRUE
TRUED) An element was made
You have 5g orange powder which you heat. As the powder is heated you noticed that a gas is given off & a silver liquid is produced. After heating you only have 1g of the orange powder left.
Which substance was definitely a compound? Why?
orange powderdecrease in mass production of two
substances
A grey colored solid is heated. The following observations were recorded
Before Heating After HeatingState solid solidColor grey blackTexture smooth granularMass 1.75g 2.5g
What statement is DEFINITELY true?A) The solid after heating is an elementB) The solid after heating is a compoundC ) The solid before heating is an element
TRUE
A) The white powder could be an element
In a lab you heat 50g of a white powder in an open container. Over time, you obtain a yellow substance with a mass of 65g.
Which statement is FALSE?
B) The white powder could be a compoundC) The yellow substance could be an elementD) The yellow substance could be a compound
Mixture: 2 or more components brought together that
can be separated physically Pure Substance
A single substance with the same properties throughout
Element Simplest form of matter that can not be
broken down Compound
2 or more elements chemically combined
To identify elements or compounds:
If mass increases, you know that you have made a compound
If mass decreases, you know that you started with a compound
Activities
Physical Science Worksheet #3 Student Study Guide- Module 1.19
to 1-22 Other Activities:
Science Quest Textbook – page 31 – 33
References
Student Study Guide – Physical Science 416/436 - MEQ
Science Quest – Grenier, Daigle, Rheaume – 1998, Cheneliere
http://www.elmhurst.edu/~chm/vchembook/101Aatoms.html
http://www.elmhurst.edu/~chm/vchembook/103Acompounds.html
Animation Factory Google Images