CHM 1025 Final Exam
240U undergoes alpha decay which results in the
loss of 2 protons and 2 neutrons from the nucleus.
What is the resulting isotope from the alpha decay?
i)90 236 U
ii)90 236 T h
iii)90 238 T h
iv)92 236 U
v) 88 236 Ra Correct Answers 90 236 Th [90
protons- 2 protons= 90 Th
[ 240- 2 protons - 2 neutrons= 236 Th
A 2.00 g sample of FeSO4xH2O is dried in an oven
and the mass of the resulting anhydrous salt is
1.0925 g. What was the value of x in the hydrated
salt? Correct Answers 7
[2.00- 1.0925= 0.9075 g
0.9075 gX 1 mole/ 18.02 g= 0.0504 moles
1.0925X 1 mole/ 151.908 g= 0.00719
0.0504/ 0.00719= 7 moles
A 2.06g sample of AgNO3•xH2O is dissolved in an
aqueous solution of excess NaCl. The resulting
AgCl precipitate is filtered off and is found to have
a mass of 1.32 g. What is the value of x in
AgNO3•xH2O? Correct Answers three
[1.32 g AgClX 1 mol/ 143.3 gX 1 mole AgNO3xH2O/
1 mol AgClX 1 mol AgNO3/ 1 mol AgNO3xH2OX
169.9 g AgNO3/ 1 mol =1.565 g AgNO3
,2.06- 1.565= 0.495 g H2O
mol AgNO3 1.565 g X 1 mol/ 169.9 g= 0.009211
mol H2O = 0.495g x (1 mol / 18.02g) = 0.02747
mole AgNO3 = 0..009211 = 1
mole H2O = 0..009211 = 3
3 moles H2O]
A certain metallic oxide M2O3 is 34.81% oxygen by
mass. What is the identity of the metal "M"?
Correct Answers Sc
[34.81 g O3X 1 mole/ 47.998 g= 0.7252 mol
65.19 g M/ (2X0.7252)= 44.946g]
A flask has a mass of 78.23 g when empty and
593.63 g when filled with water. When the same
flask is filled with concentrated sulfuric acid,
H2SO4, its mass is 1026.57 g. What is the density
of concentrated sulfuric acid? (Assume water has a
density of 1.00 g/cm3 at the temperature of the
measurement.) Correct Answers 1.840 g/cm^3
[593.63 g -78.23 g = 515.4 cm^3 water
1026.57 g - 78.23 g = 948.34 g
948.34 g/ 515.4 cm^3 = 1.840 g/cm^3]
A rectangle has sides of 5.6 m and 15.99 m. What
are the perimeter (sum of all sides) and area of the
rectangle, respectively? Correct Answers 43.18 m;
89.5 m2
, A solution is prepared by transferring 40.00 mL of a
8.50 M stock solution to a 500.0 mL volumetric
flask and diluting with water to the mark. Then,
10.00 ml of that solution is further diluted to a total
volume of 50.0 ml. What is the molarity of the final
diluted solution? Correct Answers 0.136 M
An aqueous solution contains Cu+, Ca2+, and
Fe3+. Which of the following compounds could be
added to this solution to selectively precipitate the
Ca2+ ion, but not the other ions? Correct Answers
NaF
[Read solubility chart]
An unknown substance has a density of 10.2
g/cm3, what is its density in kg/m3? Correct
Answers 10,200 kg/m^2
[1 g/cm^3= 1000 kg/m^3]
Arrange the following elements in order of
decreasing atomic radii. Pb, P, Cl, F, Si Correct
Answers Pb > Si > P > Cl > F
[Increases from top to bottom, right to left]
Arrange the following elements in order of
decreasing electronegativities. Al, Cs, Mg, Na, P
Correct Answers P > Al > Mg > Na > Cs
[Increases bottom to top, left to right]
240U undergoes alpha decay which results in the
loss of 2 protons and 2 neutrons from the nucleus.
What is the resulting isotope from the alpha decay?
i)90 236 U
ii)90 236 T h
iii)90 238 T h
iv)92 236 U
v) 88 236 Ra Correct Answers 90 236 Th [90
protons- 2 protons= 90 Th
[ 240- 2 protons - 2 neutrons= 236 Th
A 2.00 g sample of FeSO4xH2O is dried in an oven
and the mass of the resulting anhydrous salt is
1.0925 g. What was the value of x in the hydrated
salt? Correct Answers 7
[2.00- 1.0925= 0.9075 g
0.9075 gX 1 mole/ 18.02 g= 0.0504 moles
1.0925X 1 mole/ 151.908 g= 0.00719
0.0504/ 0.00719= 7 moles
A 2.06g sample of AgNO3•xH2O is dissolved in an
aqueous solution of excess NaCl. The resulting
AgCl precipitate is filtered off and is found to have
a mass of 1.32 g. What is the value of x in
AgNO3•xH2O? Correct Answers three
[1.32 g AgClX 1 mol/ 143.3 gX 1 mole AgNO3xH2O/
1 mol AgClX 1 mol AgNO3/ 1 mol AgNO3xH2OX
169.9 g AgNO3/ 1 mol =1.565 g AgNO3
,2.06- 1.565= 0.495 g H2O
mol AgNO3 1.565 g X 1 mol/ 169.9 g= 0.009211
mol H2O = 0.495g x (1 mol / 18.02g) = 0.02747
mole AgNO3 = 0..009211 = 1
mole H2O = 0..009211 = 3
3 moles H2O]
A certain metallic oxide M2O3 is 34.81% oxygen by
mass. What is the identity of the metal "M"?
Correct Answers Sc
[34.81 g O3X 1 mole/ 47.998 g= 0.7252 mol
65.19 g M/ (2X0.7252)= 44.946g]
A flask has a mass of 78.23 g when empty and
593.63 g when filled with water. When the same
flask is filled with concentrated sulfuric acid,
H2SO4, its mass is 1026.57 g. What is the density
of concentrated sulfuric acid? (Assume water has a
density of 1.00 g/cm3 at the temperature of the
measurement.) Correct Answers 1.840 g/cm^3
[593.63 g -78.23 g = 515.4 cm^3 water
1026.57 g - 78.23 g = 948.34 g
948.34 g/ 515.4 cm^3 = 1.840 g/cm^3]
A rectangle has sides of 5.6 m and 15.99 m. What
are the perimeter (sum of all sides) and area of the
rectangle, respectively? Correct Answers 43.18 m;
89.5 m2
, A solution is prepared by transferring 40.00 mL of a
8.50 M stock solution to a 500.0 mL volumetric
flask and diluting with water to the mark. Then,
10.00 ml of that solution is further diluted to a total
volume of 50.0 ml. What is the molarity of the final
diluted solution? Correct Answers 0.136 M
An aqueous solution contains Cu+, Ca2+, and
Fe3+. Which of the following compounds could be
added to this solution to selectively precipitate the
Ca2+ ion, but not the other ions? Correct Answers
NaF
[Read solubility chart]
An unknown substance has a density of 10.2
g/cm3, what is its density in kg/m3? Correct
Answers 10,200 kg/m^2
[1 g/cm^3= 1000 kg/m^3]
Arrange the following elements in order of
decreasing atomic radii. Pb, P, Cl, F, Si Correct
Answers Pb > Si > P > Cl > F
[Increases from top to bottom, right to left]
Arrange the following elements in order of
decreasing electronegativities. Al, Cs, Mg, Na, P
Correct Answers P > Al > Mg > Na > Cs
[Increases bottom to top, left to right]
