1
Which molecule contains resonance?
A) CH₄
B) NH₃
C) NO₃⁻
D) CCl₄
C (NO₃⁻ has resonance)
Identify the oxidizing agent in:
Zn + Cu²⁺ → Zn²⁺ + Cu
A) Zn
B) Cu
C) Cu²⁺
D) Zn²⁺
C (Cu²⁺ is reduced → oxidizing agent)
Which statement is TRUE about polar molecules?
A) All molecules with polar bonds are polar.
B) A molecule can have polar bonds and still be nonpolar.
C) Symmetry does not affect polarity.
D) Lone pairs never affect polarity.
B (CO₂ is example)
How many moles are present in 100. Grams of aspirin (C9H8O4 molar mass is 180.2 g/mol)?
Write out half reactions to show how many electrons are gained or lost by each species.
F2 + 2I--> I2 + 2F-
Oxidation half reaction:
2I--> I2 + 2e-
Reduction half reaction:
F2 + 2e- -> 2F-
2. What is the electron geometry of SO₂?
A) Linear
B) Trigonal planar
C) Tetrahedral
D) Bent
B (Trigonal planar electron geometry)
How many moles of O₂ are required to completely react with 4 moles of C₂H₆?
Balanced equation:
2C₂H₆ + 7O₂ → 4CO₂ + 6H₂O
A) 7
B) 14
C) 3.5
D) 10.5
A (Double everything → 7 moles O₂ needed)
What is the molar mass of Al₂(SO₄)₃?
A) 150 g/mol
B) 342 g/mol
C) 294 g/mol
D) 270 g/mol
B (~342 g/mol)
Ethanol (C2H6O, molar mass 46.07 g/mol) is synthesized by reactive ethylene (C2H4, molar mass 28.05 g/mol) with water. How many grams of ethanol are formed from 14 g of ethylene?
23g of C2H6O
best match for the two reactants in a redox reaction.
Metal
Non metal
reducing agent
oxidizing agent
Metal- Reducing agent
non-metal- Oxidizing agent
Which molecule is polar?
A) BF₃
B) CO₂
C) CCl₄
D) SO₂
D (SO₂ is bent and polar)
How many grams of CO₂ are produced from 3.0 moles of CO₂?
A) 66 g
B) 88 g
C) 132 g
D) 44 g
C (3.0 × 44 g/mol = 132 g)
Classify Reaction Type
2H₂O → 2H₂ + O₂
Zn + CuSO₄ → ZnSO₄ + Cu
NaOH + HCl → NaCl + H₂O
2Mg + O₂ → 2MgO
Decomposition
Single replacement
Double replacement
Combination
Do a mole to mole conversion:
you have 3.5 mol of C2H6 : how many mol of CO
2C2H6(g) + 5O2(g)-> 4CO(g) + 6H2O(g)
7.0 mole CO
A virus has a mass of 9.0 × 10-12 mg and an oil tanker has a mass of 3.0 × 107 kg
What is the mass of 1 mole of viruses?
Round your answer to 2 significant digits..
5.4 x 109 g
Which bond is MOST ionic?
A) C–O
B) Na–Cl
C) N–H
D) O–H
B (Na–Cl has largest electronegativity difference)
What is the molecular geometry of SF₄?
A) Tetrahedral
B) Trigonal bipyramidal
C) Seesaw
D) Square planar
C (Seesaw shape)
Balancing Equations
Balance:
___ H₂ + ___ Cl₂ → ___ HCl
___ Fe + ___ O₂ → ___ Fe₂O₃
___ C₂H₆ + ___ O₂ → ___ CO₂ + ___ H₂O
___ Al + ___ HCl → ___ AlCl₃ + ___ H₂
___ Na₃PO₄ + ___ CaCl₂ → ___ Ca₃(PO₄)₂ + ___ NaCl
H₂ + Cl₂ → 2HCl
4Fe + 3O₂ → 2Fe₂O₃
2C₂H₆ + 7O₂ → 4CO₂ + 6H₂O
2Al + 6HCl → 2AlCl₃ + 3H₂
2Na₃PO₄ + 3CaCl₂ → Ca₃(PO₄)₂ + 6NaCl
Draw the lewis structures
H₂O
NH₃
CO₂
CH₂O
SO₂
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Predict molecular geometry and bond angle:
CO₂
NH₃
H₂O
BF₃
CH₄
CO₂ → Linear, 180°
NH₃ → Trigonal pyramidal, ~107°
H₂O → Bent, ~104.5°
BF₃ → Trigonal planar, 120°
CH₄ → Tetrahedral, 109.5°
In the reaction
Fe²⁺ → Fe³⁺ + e⁻
This process is:
A) Reduction
B) Oxidation
C) Combination
D) Double replacement
B (Loss of electron = oxidation)
Which molecule has bond angles closest to 109.5°?
A) NH₃
B) H₂O
C) CH₄
D) CO₂
C (Perfect tetrahedral)
Determine if each bond is nonpolar, polar, or ionic:
a) H–F
b) C–H
c) Na–Cl
d) O–O
a) H–F → Polar
b) C–H → Nonpolar
c) Na–Cl → Ionic
d) O–O → Nonpolar
In a chemical equation,_____are on the left side of the reaction arrow and_____ are on the right side.
Reactants, Products
Calculate the molar mass of:
a) H₂O
b) CO₂
c) CaCO₃
d) NH₃
a) H₂O = 18.02 g/mol
b) CO₂ = 44.01 g/mol
c) CaCO₃ = 100.09 g/mol
d) NH₃ = 17.03 g/mol