Skip to main content
3.E: Composition of Substances and Solutions- Homework
-
-
Last updated
-
-
Save as PDF
-
For Chapter 3 you MUST know:
-
The additional polyatomic ions: cyanide ( \(\ce{CN^-}\)), nitrite ( \(\ce{NO_2^-}\)), and sulfite ( \(\ce{SO_3^{2-}}\)).
Turn in your answers for the following questions - show your work
-
For the following molecules; write the chemical formula, determine the molecular weight and determine the number of moles in exactly 1 gram.
-
carbon dioxide
-
iron (II) chloride
-
dinitrogen pentoxide
-
iron (III) sulfate
-
Name the following compounds, determine the molecular weight and determine how many moles in 8.35 grams of the compound.
-
KI
-
CaF
2
-
Cu
2
SO
4
-
N
2
O
-
LiOH
-
Give the chemical formula (or atomic symbol), molecular (or atomic) weight, and charge for the following ions:
-
sulfate
-
sulfite
-
nitrate
-
chloride
-
nitride
-
acetate
-
carbonate
-
Calculate the number of moles in:
-
45.3594 g of Ne
-
0.198669 g of Ne
-
Calculate the mass of:
-
2.00 mole of Fe
-
4.362 x 10
-5
mol of Fe
-
Describe how to prepare 250 mL of 0.12 M lithium chloride solution from solid lithium chloride.
-
Describe how to prepare 100 mL of 0.012 M lithium chloride solution from a 0.12 M lithium chloride solution.
The Following Questions are for your practice - Do Not Turn In. They include answers so you can check your work
-
What is the total mass (amu) of carbon in each of the following molecules?
-
CH
4
-
C
12
H
10
O
6
-
(a)
-
12.01 amu
-
(b)
-
144.12 amu
-
Calculate the molecular or formula mass of each of the following:
-
P
4
-
H
2
O
-
Ca(NO
3
)
2
-
(a)
-
123.896 amu
-
(b)
-
18.015 amu
-
(c)
-
164.086 amu
-
Determine the molecular mass of the following compounds:
-
-
-
(a)
-
56.107 amu
-
(b)
-
54.091 amu
-
Calculate the molar mass of each of the following:
-
S
8
-
C
5
H
12
-
(a)
-
256.528 g/mol
-
(b)
-
72.150 g mol
−1
-
Determine the mass of each of the following:
-
0.0146 mol KOH
-
10.2 mol ethane, C
2
H
6
-
(a)
-
0.819 g
-
(b)
-
307 g
-
-
answer
-
Mg
3
Si
2
H
3
O
8
(empirical formula), Mg
6
Si
4
H
6
O
16
(molecular formula)
-
Calculate the percent composition of ammonia, NH
3
to four significant figures:
-
answer
-
% N = 82.24%; % H = 17.76%
-
A compound of carbon and hydrogen contains 92.3% C and has a molar mass of 78.1 g/mol. What is its molecular formula?
-
answer
-
C
6
H
6
-
Determine the empirical and molecular formula for chrysotile asbestos. Chrysotile has the following percent composition: 28.03% Mg, 21.60% Si, 1.16% H, and 49.21% O. The molar mass for chrysotile is 520.8 g/mol.
3.3: Molarity
-
Determine the molarity for 0.444 mol of CoCl
2
in 0.654 L of solution
-
answer
-
0.679
M
-
Determine the molarity for 98.0 g of phosphoric acid, H
3
PO
4
, in 1.00 L of solution
-
answer
-
1.00
M
-
Calculate the number of moles and the mass of the solute in 2.00 L of 18.5
M
H
2
SO
4
, concentrated sulfuric acid:
-
answer
-
37.0 mol H
2
SO
4
; 3.63 × 10
3
g H
2
SO
4
-
Calculate the molarity of 0.195 g of cholesterol, C
27
H
46
O, in 0.100 L of serum, the average concentration of cholesterol in human serum
-
answer
-
5.04 × 10
−3
M
-
What is the molarity of the diluted solution when 1.00 L of a 0.250-
M
solution of Fe(NO
3
)
3
is diluted to a final volume of 2.00 L?
-
answer
-
0.125
M
-
What volume of a 0.20-
M
K
2
SO
4
solution contains 57 g of K
2
SO
4
?
-
answer
-
1.6 L