Page 253 - Chemistry eBook

Choice #3
Explanation:
Important Formul(a4s a)nd4Equations
( 1)
Sample Regents Questions
36 Which compound has the highest percent com- position by mass of strontium?
(1) SrCl2 (3) SrO (2) SrI2 (4) SrS
37 Given the formula for hydrazine:
42 Which particl matter that ca
means?
=a =a
Find the percent composition of Sr in all four choices. The highest percent composition
• Plug the values into the equation and solve.
(4) NaOH and BaSO 4
Reffy, Table T (p.12)
× 100 = 26%
2 342 (1) 􏰁73 K
(2) 73 K
Combined Gas Law
88
SrS: × 100 = 73% ( 2)
40 A 1
0
.
0
-gram s
a
m
p
l
e
MA = molarity of H+ MB = molarity of OH–
of H O(l) at 23.0°C
tleE
% error =
measured value – accepted value
n
(2) Cl and H S
Concentration
mola1r2ity0= P1V1 P2V2
(3) 200. K
oler.SO d
a
HH
June 2013 #36
NN HH
How many pairs of electrons are shared between the two nitrogen atoms?
(1) 1 (2) 2
Density
Answer
d = density d = V m = mass
is the answer. 38 Which formulas represent one ionic compound
Mole Calculations number of moles =
To find the percent composition of Sr in the four equations: gram-formula mass
and one molecular compound?
• Find the mass of the atom that you have been asked about.
• Find the mass of t(h1e e)ntiN
2 2
(3) BaCl accepted value 2
dN O 2 4
Prercmenoa
ncrur
m
(3) 3
Table T
V = volume given mass
×
0
10
22
Percent Composition
% composition by mass =
mass of part
× 100
mass of whole
SrCl : 88
× 100 = 53% SrO: 88
104 mass of solution
2 SrI :
165 88
× 10m0ass=of so8lu5te%
parts per million = × 1000000
39 Which Kelvin temperature is equal to 200.°C?
T
itr
at
ion
M
V
T = T 1 2
P = pressure
V = volume
T = temperature
43 Which form hydrocarbon?
AV
A=
MB
B
VA = volum2e of acid VB = volume of base
moles of solute
liter of solution
(4) 473 K
e diagram re n not be brok
Key
tom of one el tom of a diffe
ula represe
absorbs 209 joules of heat. What is the final
p
UNIT 6: MATH IN CHEMISTRY © 252
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