Review

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Review
Review
Chemical and Physical Changes
Chemical and physical properties
Conservation of mass
Reaction Rates
For each of the following, give an example of what
you might see in a chemical reaction that would
indicate…..:
a. color change
b. energy change
c. Precipitate
d. gas formation
For each of the following, give an example of what
you might see in a chemical reaction that would
indicate…..:
a. color change color disappears or you get a
color that isn’t the result of color wheel
mixing (ex..yellow + blue = green, this doesn’t
necessarily indicate a color change)
b. energy change temperature change, got
hotter or colder, light produced
c. Precipitate formation of a solid
d. gas formation bubbles/foaming
• Which of the following would increase the
rate of a reaction?
a) Increase temperature
b) Decrease concentration
c) Adding a catalyst
d) Decreasing temperature
e) Decreasing the surface area
• Which of the following would increase the
rate of a reaction?
a) Increase temperature
b) Decrease concentration
c) Adding a catalyst
d) Decreasing temperature
e) Decreasing the surface area
Which of these equations are
balanced?
1. H2CO3 → H2O+ CO2
2. NH3 + H2O → 3NH4OH
3. SnO2 + H2 → Sn + H2O
Which of these equations are
balanced?
1. H2CO3 → H2O+ CO2
2 H, 1 C, 3 O  2 H, 1 C, 3 O
2. NH3 + H2O → 3NH4OH
1 N, 5H, 1 O  3 N, 15 H, 3 O
3. SnO2 + H2 → Sn + H2O
1 Sn, 2 O, 2H  1 Sn, 1 O, 2H
What can you do to balance this
equation.
2. NH3 + H2O → 3NH4OH
What can you do to balance this
equation.
2. NH3 + H2O → 3NH4OH
NH3 + H2O → NH4OH
Which of these reactions is
exothermic…how do you know?
Which is endothermic…how do you
know?
1. H2CO3 → H2O+ CO2 + energy
2. NH3 + H2O + energy → 3NH4OH
3. SnO2 + H2 → Sn + H2O
Living things obtain energy through this
reaction
O₂ + C₆H₁₂O₆  CO₂ + H₂O + energy
The process reflected by this equation is____
1. If the masses of the reactants are 19g and 24g,
what will be the mass of the products?
2. In the following equation:
SnO2 + 2 H2 → Sn + 2 H2O
The mass of SnO2 is 6g, the mass of Sn is 2g, and the
mass of H2O is 8 grams, what is the mass of H2 ?
__________________  ______________
(what are substances on this side of the arrow called?)
(what are substances on this side of the arrow called?)
Matching…
1. products
2. Chemical change/reaction
3. Catalyst
4. Reactant
A. A substance that increases the rate (speeds up) of a
chemical reaction but is not consumed in the reaction
B. Every chemical reaction forms at the end of the reaction
C. Changes the way in which atoms are arranged by causing
bonds between the atoms to break and new bonds to
form between different atoms.
D. A substance present at the beginning of a chemical
reaction
matching
1.
2.
3.
4.
A.
Specific Heat
Precipitate
Temperature
Surface Area
Affects the rate of a chemical reaction by changing the speed at
which particles of reactants move
B. Affects the rate of a chemical reaction by increasing the number
of molecules of one reactant that are exposed to the other
reactant.
C. A solid product that sometimes forms when chemicals in liquids
react
D. The amount of energy required to raise the temperature of 1g of
material 1 degree
1 Which is a more suitable material for roofers to use when removing iron
nails from a yard: magnets or water?
2 Which is a more suitable material to “foil” teeth in dental work: Carbon (C)
Tin (Sn)?
4 Which is a more suitable material for power lines: Selenium (Se) or
Tungsten (W)
5 Which is a more suitable material for use in water pipes: Potassium (K) or
Copper (Cu)?
6 Which is a more suitable material to stir boiling liquid for a long time: a
Silicon (Si) spoon or an Aluminum (Al) spoon?
7
Which is a more suitable material for creating a reflective surface on the
back of a mirror: Silver (Ag) or Arsenic (As)?
1 Which is a more suitable material for roofers to use when removing iron nails
from a yard: magnets or water? Becaue they are metals and a physical
property of metal is magnetism.
2 Which is a more suitable material to “foil” teeth in dental work: Carbon (C) Tin
(Sn)? Because metals are malleable and nonmetals are brittle. Tin is a metal,
carbon is a nonmetal.
4
Which is a more suitable material for power lines: Selenium (Se) or Tungsten
(W) Because metals are conductive, tungsten is a metal and selenium is a non
metal
5 Which is a more suitable material for use in water pipes: Potassium (K) or
Copper (Cu)? Because copper is a transition metal which is stable and
Potassium is a member of the alkali metal group which is unstable and reacts
with water.
6 Which is a more suitable material to stir boiling liquid for a long time: a Silicon
(Si) spoon or an Aluminum (Al) spoon? Because silicon is a metalloid and
therefore conducts heat poorly, aluminum is a metal and conducts heat….an
aluminum spoon gets HOT
7 Which is a more suitable material for creating a reflective surface on the back of
a mirror: Silver (Ag) or Arsenic (As)? Silver is a metal and therefore shiny,
Arsenic is a nonmetal and therefore dull. A mirror needs to have a shiny
backing so it will reflect light and your image
• Your brother finds a golden-colored cube at a
flea market. The price is $100, and your
brother is sure that it is gold. You pull out
your old geology textbook and look up gold in
the mineral table, and read that its density is
19.3 g/cm3. You test the cube and find that it
displaces 8 cm3 of water, and has a mass of
40g. What is the cube’s density? Is it gold?
Should you buy it?
The gold colored cube has a density of 40/8 = 5 g.
It does not have the same density as gold,
therefore it is not gold.

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