Question: salt water is an example of
a.Element
b.Substance
c.Homogeneous mixture *
d.Heterogeneous mixture
e.compound
Sheldon wants Leonard to honor
room mate agreement section 8
subsection 2b by using precisely no
more than 172.5 cm3 of space for
his visiting non-human guest
(density of guest=2.3 lb / 1.2
quarts). Choose the best equation
to find out if Leonard’s 4.11 pound
non human guest, can stay
4.11 lb x 2.3 lb x 1.06 quart x 1 L
x 1 mL = 7.9 x 10-3 cm-3
1.2 quart 1 L
1000 mL 1 cm3
Yes, non human guest is allowed. (units = lb2/cm3)
a.
b.
c.
d.
4.11 lb x 1.2 quart x 1 L
x 1000 mL x 1 cm3 = 2000 cm3
2.3 lb
1.06 quart 1 L
1 mL
(2.0 x 103 cm3)
No, non human guest is not allowed. * (correct answer)
1.2 quart x 1L
x 1000 mL x 1 cm3 = 490 cm3/lb
2.3 lb
1.06 quart 1 L
1 mL
Yes, non human guest is allowed. (wrong unit for volume)
1
x 2.3 lb
x 1.06 quart x 1 L
x 1 mL = 4.9 x 10-4 cm -3
4.11 lbs 1.2 quart
1L
1000 mL 1 cm3
Yes, non human guest is allowed. (cm-3 not volume unit)
e. None are correct. Leonard will veto the room mate agreement & will
accept non human guest into the apartment regardless.
For the following symbol
a.
b.
c.
d.
e.
17
8
O
17 is the # of neutrons & protons
8 is the number of protons
17-8 = number of neutrons
Statements a and b are true.
a,b,c are true. *
Given the periodic table, choose the
one incorrect statement.
a. Periods go horizontally across the table.
Groups are vertical.
b. The alkaline earth metal elements are in
group IA and the alkali metals start with Be
and end with Ra. * (backwards IA alkali metal)
c. Noble gases consist of He to Rn and are very
inert to chemical reaction.
d. Halogens consist of F,Cl,Br, I and At.
e. The chalcogens consist of group VIA.
38
For the element Sr
87.62
(this is what you see in periodic table)
a. The number of protons = 38 & the
number of electrons = 38. The number
of neutrons = 87.62 - 38
b. The element is in group IIA and has a
charge of negative 2. (not true, +2)
c. Sr(NO3)2 is named strontium nitrate.
d. Statements a and c are true. *
e. Statements a,b are true.
Al (s) + HCl  AlCl3 + H2
The coefficients are:
a. 1, 1, 1, 1
b. 2,3,1,2
c. 2,6,2,3*
d. 1,3,1,3
e. 1,3,1,1
The molecular weight of H2SO4 is:
a.
b.
c.
d.
MW=2(1.01) x 32.0 x 4(16.0)
MW= 1.01 + 32.0 + 16.0
MW = 2(1.01) + 32.0 + 4(16.0) *
MW= 2(1.01) + 16.0 + 4 (8.0)
Choose the one incorrect statement:
a. 1 mole of the element Li has 6.02 x 1023 atoms
of Li and weighs 6.94 grams
b. 1 mole of Ca(OH)2 has 6.02 x 10 23 molecules
of Ca(OH)2 and weighs [40.1+2(16.0+1.01)]=
74.12grams)
c. 1 mole of SF6 has 4 x (6.02 x 1023) atoms of F
and has 4 x 19.0 = 76 grams of F (6)incorrect
d. 1 molecule of Ca(OH)2 weighs 74.12 amu
e. 1 mole of N2 has 2 x (6.02 x 1023) atoms of N
and 6.02 x 10 23 molecules of N2
Choose the one best statement.
a. 1 mole has 6.02 x 10 23 atoms of an element.
b. A mole weighs the same as the atomic mass
of the element in grams (ex: molar mass of
Mg is 24.3 grams)
c. 1 mole of a molecule has 6.02 x 10 23
molecules.
d. 1 mole weighs the same as the molecular
weight of the molecule in grams. (ex: molar
mass of MgCl2 is [24.3 + 2(35.5)] grams)
e. All statements are correct. best statement
How many atoms of Cl is in 354.2 g of MgCl2
[FW (MgCl2) = 95.3 g] ?
a.
95.3 g MgCl2 x 354.2 g MgCl2 x 6.02 x 1023 atoms Cl
mol MgCl2
35.4 g Cl
b. 354.2 g MgCl2 x 1 mol MgCl2 x 2 mol Cl x 6.02x1023 atoms Cl
correct
95.3 g MgCl2 1 mol MgCl 2
1 mol Cl
c. 354.2 g MgCl2 x 95.3 g MgCl2 x 1 mol MgCl2 x 6.02x1023atomCl
1mol MgCl2
2 mol Cl
1 mol Cl
d. There is not enough information to answer this question – duh!
For the reaction 2H2 + O2  2H2O, if you start with 2.0
grams of O2 [MW (H2) = 2.02, MW (O2) = 32.0, MW
(H2O) =18.02] (Choose the one best statement.)
a.grams(H2O)=2.0 g O2x 1mol O2 x 1 mol H2O x 18.02 g H2O
formed
32.0 g O2 1 mol O2
1 mol H2O
b.grams (H2)=2.0 gO2 x 1 mol O2 x 2 mol H2 x 2.02 g H2
(consumed)
18.02 g O2 1 mol O2
1 mol H2
c.moles (H2O)=2.0 g O2 x 1 mol O2 x 2 mol H2O correct
formed
32.0 g O2 1 mol O2
d. moles (H2)=2.0 g O2 x 1 mol O2 x 1 mol H2
(consumed)
32.0 g O2 1 mol O2
e. All statements are correct.