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Unformatted text preview: Cypress Creek HS
TAKS Objective 4:
Structure & Properties of Matter
Structure A Quick Density Review
Quick ratio of mass to volume high density: a lot of mass in a small
volume Density of water is 1 g/mL Density = mass
v Evaluating Density
Compare the mass,
volume and density of
sample A and B
below. What would happen
to the density of B if
the sample were cut
Figure 1 1
A A B B Mass, Volume, and Density
Figure 1 1
VA __ VB
A B DA __ DB = B B A block of maple wood with a volume of
405 cubic centimeters and a density of
0.67g/cm3 is sawed in half. The density of
the two smaller blocks is now.
A One-fourth the original density
B One-half the original density
C Two times the original density
D The same as the original density Evaluating Density How
How does the density of the Diet Coke compare
to that of the Coke? Explain.
to If the density of water is 1 g/mL, then what can
you infer about the density of each can of soda? The table shows some properties
of four different substances. The
picture shows a solid
sphere of one of the four
substances in a water-ethanol
solution (D = 0.9199 g/mL). The
sphere is most likely composed
of which substance?
A Substance Q
B Substance R
C Substance S
D Substance T D = 0.9199 g/mL The
The instruments below
show the mass and volume
difference of an irregularly
shaped object. Using the
data, the density of the
object is ____________.
A 25.4 g/mL
B 4.40 g/mL
C 0.019 g/mL
D 5.24 g/mL Answer Explanation
Answer • Recall, Density = Mass/Volume Here, the mass is shown on the balance as 22 g. The volume of the irregular-shaped object must be found
by using the water displacement method. The initial
volume of water reads 20.0 mL and the final volume of
water reads 25.0 mL. Subtract the final volume by the
initial volume to determine the volume of the object, 5.0
mL. D = M/V = 22 g/5.0 mL = 4.40 g/mL. Therefore, answer
choice B is correct.
This pipette is filled with a
20% NaOH solution. The
solution is at 20°C and has
a density of 1.23 g/mL.
According to this
information, what is the
mass of this NaOH
A 3.88 g
D =m 1.23 g = _m_
B 15.7 g
1 mL 19.4 mL
C 23.9 g
m=1.23g x 19.4mL = 23.9 g
D 24.6 g
24.6 1 mL
Answer is C Two
Two scientists decided to compare the densities
of a crown and a block of metal. The scientists
found the volume of the block and computed its
density based on its known mass (2,400 g). The
diagram below shows the dimensions of the block
of metal that the scientists measured. What is
the density of the block of metal?
the Answer: ____________ g/cm3 Answer Explanation
D = M/V The mass is given in the problem;
M = 2400 g.
2400 To determine the volume of the box:
V = length x width x height V = 5 cm x 5 cm x 5 cm = 125 cm3
D = 2400 g/125 cm3 = 19.2 g/cm3 PERIODIC TABLE
Another tool for success on the
test. Atomic Number
(# of protons or electrons) Element Symbol
(Average mass of all
isotopes) + ++
++ + 14 Si
Silicon Element Name The Periodic Table
#protons identifies the element
#p = #e, for neutral atoms Periodic Table
Rows are called “periods.”
7 This is period number 3.
The elements in this row
have their electrons located
in 3 energy levels. Columns on the periodic table are called “groups” or
“families.”The groups are numbered from
13 14 15 16 17 2
3 4 5 6 7 8 9 10 11 12 This is group 1.
Families have similar
but not identical
physical and chemical
characteristics Chemical Properties
Groups: have similar
chemical and physical
properties Metals vs Nonmetals
•Form (+) ions Nonmetals:
•Form () ions •Lose/donate electrons •Gain/accept electrons •Combine/react with nonmetals •Combine/react with metals The
oxygen are most
similar to the bonding
characteristics of —
sulfur A certain atom has a nucleus containing
six protons and eight neutrons and has six
electrons orbiting the nucleus. This atom
is a form of the element —
D calcium valence electrons:
# electrons in the outermost energy level.
Determined by the ones place NOT the 10’s
place in the group number.
2 13 14 15 16 17
++ + Label Your Periodic Table
Label CIRCLE THE GROUP NUMBERS
Groups = Similar Chemical Properties
= Valence Practice Using Your Periodic Table
An isotope of which element has an
atomic number of 7 and a mass number of
D. Magnesium Practice Using Your Periodic Table
The table shows the electron configuration
of which neutral atom?
ELECTRON CONFIGURATION A. Sodium
D. Arsenic Energy Level 1 2 # Electrons 2 85 3 Practice Using Your Periodic Table
An element from group 2 on the periodic
table would bond easiest with an element
from which other group?
D. 16 Chemical & Physical Properties
Chemical The ability or
inability of matter to
with other matter
with Physical Measurable Observable by our
senses Classifying Matter
Element Compound Contains one type of atom,
found on periodic table
2 or more elements
Chemical Mixture elements and/or
compounds that are
physically combined and
different materials are
Solutions are homogenous
mixtures H2O Chemical vs. Physical Changes
Chemical Chemical Change Atoms
combine in a new way
combine Represented by a
Observations: Color change Temperature change Gas produced Solid formed Physical Same
Same Change combination of atoms
Change in shape, size
or Change in phase Ratios in Chemical Formulas
Ratios A chemical formula is a combination of element symbols
and subscripts that tells you the ratio of elements. (LabAids Inc.)
H2O = 2 atoms H to 1 atom O
Fe2O3 = 2 atoms Fe to 3 atoms of O 2 Fe : 3 O
*NaCl = 1 atom Na to 1 atom Cl
1 Na : 1 Cl
*For NaCl, the ratio is 1:1 because Na is a Group 1
element with 1 valence electron (loses 1e-) and Cl is a
Group 17 element with 7 valence electrons (gains 1e-).
Group The ionic compounds that results from combining Group
2 and Group 16 elements have a 1:1 ratio because—
D Group 2 elements are electrically neutral.
Group 2 elements have two valence electrons.
Group 2 elements contain neutrons in the
Group 2 contains more elements than other
Elements from Group 1 on the Periodic Table
will form compounds with elements from Group
15. An example would be potassium phosphide
(K3P). A compound with elements from these
two groups will always combine with a ratio of
__Group 1 : __Group 15.
3:1 Conservation of Mass
Conservation Both sides of a chemical reaction must have the same
mass: mass reactants = mass products.
mass: 2HgO 2Hg + O2 10g 9.3g + ? 10 g = 0.7 + 9.3 g ...But what happened to the O2? This is the Law of the Conservation of Mass –
Matter is neither created nor destroyed. According to the law of conservation of mass, how much
zinc was present in the zinc carbonate?
A 408 g
B 256 g
C 104 g
D 40 g Is mass conserved?
H2 + O2
What do we need to do? To be balanced, there must be the same number of atoms
of each element on both sides of the equation.
of 2H2 + O2
2H 2H2O Reactants: Products: 4H 4H 2O 2O Practice balancing the following
chemical __Al + __O2 __Al2O3
__Al __C2H4 + __O2 __CO2 + __H2O
__C __Zn(NO3)2 + __Na2CO3 __ZnCO3 + __NaNO3
__Zn(NO Good Luck!
Make good use of your periodic table and
Get a good night sleep.
Study the night before, your brain will
continue to process while you sleep.
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- Spring '11