1. Total 1.5 point
(If an exact chemical formula is presented + 1.0 point,
if the exact mass of carbon dioxide generated is given + 0.5 point)
C2H5OH + 3O2 → 2CO2 + 3H2O
Solution A) Stoichiometric Methods
46.0 g of ethanol = 0.998 mol ≒ 1.00 mol
96.0 g of oxygen = 3.00 mol
54.0 g of water = 3.00 mol
As 3.00 mol of water is produced, 2.00 mol of carbon dioxide is produced.
So, 2.00 mol * 44.01 g/mol = 88.0 g of carbon dioxide is produced.
Solution B) Conservation of mass
For closed systems, total mass of the reactants must be equal to the mass of the
products.
Reactants (46.0 g + 96.0 g) = Products (54.0 g + x)
x = 88.0 g of carbon dioxide
2. Total 1.5 point ( 0.25 / each question )
𝑎) 178𝑂
𝑏) 37
17𝐶𝑙
𝑐) 60
27𝐶𝑜
𝑑) 57
26𝐹𝑒
𝑒) 131
53𝐼
𝑓) 73𝐿𝑖
3. Total 2.0 point (0.4/ each question) 1. False, charge of neutron is 0; Nucleus contains proton and neutron
2. False, most of space is empty
3. False, nucleus contains most of the mass of the atom.
4. True.
5. False, the number of protons in neutral and electrons are equal; There is no numerical
relationship between neutrons and electrons.
4. Total 1.2 point ( 0.3 / each question )
(a) Te, Tellurium
(b) Rb, Rubidium
(c) Ar, Argon
(d) At, Astatine
5. Total 1.8 point ( 0.2 / each question )
(a) Iron(III) chloride
(b) Nitrogen dioxide
(c) Calcium oxide
(d) Aluminum sulfide
(e) Iron(III) phosphate
(f) Diphosphorus pentasulfide
(g) Sodium peroxide
(h) Nitric acid
(i) Hydrosulfuric acid, dihydrogen sulfide, hydrogen sulfide (common name)
6. Total 1.0 point ( 0.2 / each question )
(a) HBr
(b) Pb(CO3 )2
(c) SF6
(d) Hg 2 Cl2
(e) CrO3