Download Chemistry Experiments

with Dr. Doumit
The Explosion
2H2 (g) + O2 (g) ---------------- 2H2O (g)
An example of a combustion reaction!
Hydrogen Balloon ignited by a flame.
Observing Chemical Change
Properties of Copper
Pennies are coated with
copper. Which are
physical properties of
copper and which are the
chemical properties?
What are two additional
properties?
Observing Chemical Change
Breaking and Making Bonds
Describe what happens to the bonds in each of the steps as oxygen
reacts with magnesium.
Describing Chemical Reactions
Chemical Formulas
The formula of a compound
identifies the elements in the
compound and the ratio in which
their atoms or ions are present.
What are the missing chemical
formulas in the table?
Describing Chemical Reactions
Modeling a Chemical Equation
Like a skateboard, a chemical equation has a basic structure. How
many complete skateboards can be made from the parts pictured?
Describing Chemical Reactions
Molecules of nitrogen (N2) and hydrogen (H2) react to form ammonia
(NH3). How many H2 and N2 molecules are needed to yield two
molecules of NH3?
Describing Chemical Reactions
Balancing Chemical Equations
What are the four steps in balancing chemical equations?
Step 1
Step 2
Step 3
Step 4
Describing Chemical Reactions
Types of
Reactions
What is
each type
of reaction
represented?
Controlling Chemical Reactions
Activation Energy
A chemical reaction needs a push to the “top of the mountain” to get started.
Where has enough activation energy been added to start the reaction?
Controlling Chemical Reactions
Graphs of Exothermic and Endothermic Reactions
Each of the graphs shows the amount of energy before and after the
reaction. On each graph, determine whether energy is absorbed or
released.
Controlling Chemical Reactions
Catalysts
Adding a catalyst speeds up a chemical reaction. How would the
energy graph change for the same chemical reaction if a catalyst were
used?
Crookes Tube
(Cathode ray tube)
Deflection of electrons
on a magnetic field.
If a magnetic field is placed
across the beam (with the north
pole indicated by tape in front),
the beam is deflected downward
as shown (by Steve Grabowski) in
Figure 110-3.
If the magnetic field is reversed
(so that the north pole is in the
back) the beam is deflected
upward as shown in Figure 110-4.
Why it Works
 A magnetic field does not exert a force on a stationary
electron. However, a magnetic field does produce a
force on a moving electron. The electron's motion, the
magnetic field, and the force are all at right angles to
each other.
The Point
 Properties of the electron can be determined by observing
its behavior in electric and magnetic fields.
 The electron is negatively charged. The force produced by a
magnetic field on a moving beam of electrons can be
described by the right-hand rule, in which the thumb
indicates the direction of the force, the index finger
indicates the direction of the motion of the electrons, and
the rest of the fingers indicate the direction of the
magnetic field.
 Careful analysis of electric and magnetic fields on an
electron beam determines the charge to mass ratio of the
electron.