Chapter 5: The Mole and Chemical Formulas
Perform the following calculation:
2.14 mol of sodium sulfide, Na2S, to grams.
167 g Na2S
Draw the Lewis structure and give the electron pair geometry and molecular shape:
CH3Cl
EG: Tetrahedral
MS: Tetrahedral
Write an unbalanced chemical equation to represent the following:
Solid magnesium and oxygen gas react to form solid magnesium oxide.
Mg(s) + O2(g) → MgO(s)
Consider the following balanced chemical equation:
4 Fe(s) + 3 O2(g) → 2 Fe2O3(s)
How many moles of iron are required to react with 24.0 moles of oxygen?
32.0 mol Fe
Silicon tetrachloride (SiCl4) can be prepared by heating Si in chlorine gas:
Si(s) + 2 Cl2(g) → SiCl4(l)
How many moles of chlorine were used to produce 0.507 mol of SiCl4?
1.01 mol Cl2
Perform the following calculation:
7.98*1023 atoms of argon (Ar) to grams.
52.9 g Ar
Draw the Lewis structure and give the electron pair geometry and molecular shape:
SO32-
EG: Tetrahedral
MS: Trigonal pyramidal
Write an unbalanced chemical equation to represent the following:
Aqueous potassium hydroxide and phosphoric acid react to to form aqueous potassium phosphate and water.
KOH(aq) + H3PO4(aq) → K3PO4(aq) + H2O(l)
Consider the following balanced chemical equation:
4 Fe(s) + 3 O2(g) → 2 Fe2O3(s)
How many moles of oxygen are required to produced 12.5 moles of Fe2O3?
18.8 mol O2
Determine the mass of potassium in 8.11 x 1023 atoms of K.
52.7 g K
Find the percent composition of ammonium phosphate: (NH4)3PO4
28.18% N
8.11% H
20.78% P
42.93% O
Draw the Lewis structure and give the electron pair geometry and molecular shape:
H2CO
EG: Trigonal planar
MS: Trigonal planar
Is this compound soluble or insoluble?
Ca(OH)2 (aq)
Soluble
How many moles of propane gas, C3H8, react with 4.35 mol of oxygen gas given the unbalanced chemical equation?
C3H8(g) + O2(g) → CO2(g) + H2O(g)
0.870 mol C3H8
Which of the following molecules are polar?
CO
CO2
SO2
BeCl2
CO and SO2
Determine the empirical formula for a compound with the following percent compositions: 40.0% carbon, 6.7% hydrogen, and 53.3% oxygen.
CH2O
Draw the Lewis structure and give the electron pair geometry and molecular shape:
C2H4
No matter which carbon you choose, they are both central atoms:
EG: Trigonal planar
MS: Trigonal planar
Balance the following chemical equation:
Al(s) + CuO(s) → Al2O3(s) + Cu(s)
2 Al(s) + 3 CuO(s) → Al2O3(s) + 3 Cu(s)
Consider the following unbalanced chemical equation:
Cu2O(s) + O2(g) → CuO(s)
Determine the mass (in grams) of CuO formed from the reaction of 92.0 g Cu2O.
102 g CuO
Consider the following reaction:
B2H6(g) + O2(g) → HBO2(g) + H2O(l)
Determine the mass of HBO2 formed from 40.0 g of B2H6.
127 g HBO2
Lactose (or milk sugar) is a disaccharide (two sugar compound) that is found in milk and dairy products. Find the percent composition of lactose, C12H22O11.
42.11% C
6.48% H
51.42% O
Draw the Lewis structure and give the electron pair geometry and molecular shape:
HCN
EG: Linear
MS: Linear
Balance the following chemical equation:
Be2C + H2O → Be(OH)2 + CH4
Be2C + 4 H2O → 2 Be(OH)2 + CH4
Consider the following unbalanced chemical equation:
Cu2O(s) + O2(g) → CuO(s)
Determine the mass (in grams) of CuO formed from the reaction of 12.0 g O2.
119 g CuO
Write a balanced chemical equation for the following:
Solid calcium carbide (CaC2) reacts with water to form gaseous acetylene (C2H2) and aqueous calcium hydroxide.
CaC2(s) + 2 H2O(l) → C2H2(g) + Ca(OH)2 (aq)