Question

why?
recognizing patterns allows us to predict future behavior. weather experts use patterns to predict danger-
ous storms so people can get their families to safety. political analysts use patterns to predict election out-
comes. similarly, chemists classify chemical equations according to their patterns to help predict products
of unknown but similar chemical reactions.
model 1 – types of reactions
set a
$4fe(s) + 3o_2(g) \
ightarrow 2fe_2o_3(s)$
$n_2(g) + 3h_2(g) \
ightarrow 2nh_3(g)$
$2so_2(g) + o_2(g) \
ightarrow 2so_3(g)$
$mgo(s)+ h_2o(l) \
ightarrow mg(oh)_2(aq)$
$p_2o_5(g) + 3h_2o(l) \
ightarrow 2h_3po_4(aq)$
$so_3(g) + h_2o(l) \
ightarrow h_2so_4(aq)$
set b
$mgco_3(s) \
ightarrow mgo(s) + co_2(g)$
$8li_2s(s) \
ightarrow 16li(s) + s_8(s)$
$2h_2o(l) \
ightarrow 2h_2(g) + o_2(g)$
$2kclo_3(s) \
ightarrow 2kcl(s) + 3o_2(g)$
$2na_2o_2(s) \
ightarrow 2na_2o(s) + o_2(g)$
$(nh_4)_2co_3(s) \
ightarrow 2nh_3(g) + h_2o(l) + co_2(g)$
set c
$2fecl_3(aq) + 3zn(s) \
ightarrow 2fe(s) + 3zncl_2(aq)$
$2al(no_3)_3(aq) + 3ca(s) \
ightarrow 3ca(no_3)_2(aq) + 2al(s)$
$mg(s) + cuso_4(aq) \
ightarrow mgso_4(aq) + cu(s)$
$2al(s) + 6hcl(aq) \
ightarrow 2alcl_3(aq) + 3h_2(g)$
$cl_2(g) + 2nabr(aq) \
ightarrow 2nacl(aq) + br_2(l)$
$znbr_2(aq) + f_2(g) \
ightarrow znf_2(aq) + br_2(l)$
set d
$agno_3(aq) + nacl(aq) \
ightarrow agcl(s) + nano_3(aq)$
$2hno_3(aq) + mg(oh)_2(aq) \
ightarrow mg(no_3)_2(aq) + 2h_2o(l)$
$na_2co_3(aq) + cacl_2(aq) \
ightarrow caco_3(s) + 2nacl(aq)$
$fes(s) + 2hcl(aq) \
ightarrow h_2s(g) + fecl_2(aq)$
$hcl(aq) + naoh(aq) \
ightarrow h_2o(l) + nacl(aq)$
$febr_3(aq) + k_3po_4(aq) \
ightarrow fepo_4(s) + 3kbr(aq)$

1. the chemical equations in model 1 contain the phase notations (s), (l), (g), and (aq). match

each symbol with its meaning.
dissolved in water liquid solid gas

1. based on the examples provided, which set(s) of reactions in model 1 typically involve ions in

solution (a, b, c or d)?

1. based on the examples provided, which set(s) of reactions in model 1 typically involve gases

and/or solids?

Explanation:

Question 1

• (s) stands for solid, representing a substance in its solid state (e.g., Fe(s), MgO(s)).
• (l) stands for liquid, representing a substance in its liquid state (e.g., H₂O(l)).
• (g) stands for gas, representing a substance in its gaseous state (e.g., O₂(g), CO₂(g)).
• (aq) stands for aqueous, meaning the substance is dissolved in water (e.g., Mg(OH)₂(aq), AgNO₃(aq)).

• Set D has reactions with aqueous solutions (aq) like \( \text{AgNO}_3(\text{aq}) + \text{NaCl}(\text{aq})

ightarrow \text{AgCl}(\text{s}) + \text{NaNO}_3(\text{aq}) \), \( \text{HCl}(\text{aq}) + \text{NaOH}(\text{aq})
ightarrow \text{H}_2\text{O}(\text{l}) + \text{NaCl}(\text{aq}) \), etc. Set C also has aqueous reactants (e.g., \( 2\text{FeCl}_3(\text{aq}) + 3\text{Zn}(\text{s})
ightarrow 2\text{Fe}(\text{s}) + 3\text{ZnCl}_2(\text{aq}) \)) and involves ions in solution (redox or displacement reactions with ions).

• Set A and B have more solid/gas/liquid (non - aqueous ion - free or less ionic) reactions. So Sets C and D involve ions in solution.

• Set A: Reactions have solids (e.g., Fe(s), MgO(s)), gases (e.g., O₂(g), N₂(g)), and liquids (e.g., H₂O(l)). For example, \( 4\text{Fe}(\text{s}) + 3\text{O}_2(\text{g})

ightarrow 2\text{Fe}_2\text{O}_3(\text{s}) \), \( \text{N}_2(\text{g}) + 3\text{H}_2(\text{g})
ightarrow 2\text{NH}_3(\text{g}) \), \( \text{MgO}(\text{s})+\text{H}_2\text{O}(\text{l})
ightarrow \text{Mg(OH)}_2(\text{aq}) \).

• Set B: Reactions have solids (e.g., MgCO₃(s), Li₂S(s)) and gases (e.g., CO₂(g), O₂(g)). For example, \( \text{MgCO}_3(\text{s})

ightarrow \text{MgO}(\text{s}) + \text{CO}_2(\text{g}) \), \( 2\text{H}_2\text{O}(\text{l})
ightarrow 2\text{H}_2(\text{g}) + \text{O}_2(\text{g}) \).

• Set C: Reactions have solids (e.g., Zn(s), Al(s)) and aqueous solutions (but also products like Fe(s)). For example, \( 2\text{FeCl}_3(\text{aq}) + 3\text{Zn}(\text{s})

ightarrow 2\text{Fe}(\text{s}) + 3\text{ZnCl}_2(\text{aq}) \), \( \text{Cl}_2(\text{g}) + 2\text{NaBr}(\text{aq})
ightarrow 2\text{NaCl}(\text{aq}) + \text{Br}_2(\text{l}) \) (has gas and liquid).

• Set D: Reactions have solids (e.g., AgCl(s), CaCO₃(s)) and aqueous solutions. For example, \( \text{AgNO}_3(\text{aq}) + \text{NaCl}(\text{aq})

ightarrow \text{AgCl}(\text{s}) + \text{NaNO}_3(\text{aq}) \), \( \text{FeS}(\text{s}) + 2\text{HCl}(\text{aq})
ightarrow \text{H}_2\text{S}(\text{g}) + \text{FeCl}_2(\text{aq}) \) (has gas and solid). So all sets (A, B, C, D) involve gases and/or solids.

Answer:

• (s): solid
• (l): liquid
• (g): gas
• (aq): dissolved in water

Question 2