Question

complete these equations, balance and classify the type of reaction.
a. solid sulfur plus oxygen gas yields sulfur dioxide gas.
____ + o₂ (g) → ____
reaction type: ______
b. nitrogen gas plus hydrogen gas yields ammonia (nh₃) gas.
n₂ (g) + ____ → ____
reaction type: ______
c. aqueous calcium chloride plus a solution of silver nitrate produces aqueous calcium nitrate precipitate of silver chloride.
____ + __ → __ + ____
reaction type: ______
d. a solution of sodium bromide plus chlorine gas yields aqueous sodium chloride and bromine.
____ + cl₂ (g) → __ + ____
reaction type: ______

Explanation:

Step1: Write the unbalanced equation for A

Solid sulfur is \(S(s)\) and sulfur dioxide is \(SO_{2}(g)\). The un - balanced equation is \(S(s)+O_{2}(g)\to SO_{2}(g)\). Since there is 1 S atom and 2 O atoms on both sides, it is already balanced. This is a combination reaction (also called synthesis reaction) as two substances combine to form one product.

Step2: Write the unbalanced equation for B

Hydrogen gas is \(H_{2}(g)\) and ammonia is \(NH_{3}(g)\). The un - balanced equation is \(N_{2}(g)+H_{2}(g)\to NH_{3}(g)\).

• Balance N: There are 2 N atoms on the left. So, we put a 2 in front of \(NH_{3}\): \(N_{2}(g)+H_{2}(g)\to 2NH_{3}(g)\).
• Balance H: There are 6 H atoms on the right. So, we put a 3 in front of \(H_{2}\). The balanced equation is \(N_{2}(g)+3H_{2}(g)\to 2NH_{3}(g)\). This is a combination reaction.

Step3: Write the unbalanced equation for C

Calcium chloride is \(CaCl_{2}(aq)\), silver nitrate is \(AgNO_{3}(aq)\), calcium nitrate is \(Ca(NO_{3})_{2}(aq)\) and silver chloride is \(AgCl(s)\). The un - balanced equation is \(CaCl_{2}(aq)+AgNO_{3}(aq)\to Ca(NO_{3})_{2}(aq)+AgCl(s)\).

• Balance Cl: There are 2 Cl atoms on the left. So, we put a 2 in front of \(AgCl\): \(CaCl_{2}(aq)+AgNO_{3}(aq)\to Ca(NO_{3})_{2}(aq)+2AgCl(s)\).
• Balance Ag: There are 2 Ag atoms on the right. So, we put a 2 in front of \(AgNO_{3}\). The balanced equation is \(CaCl_{2}(aq)+2AgNO_{3}(aq)\to Ca(NO_{3})_{2}(aq)+2AgCl(s)\). This is a double - displacement reaction (also called metathesis reaction) as the cations and anions of two ionic compounds exchange partners.

Step4: Write the unbalanced equation for D

Sodium bromide is \(NaBr(aq)\), sodium chloride is \(NaCl(aq)\) and bromine is \(Br_{2}(l)\). The un - balanced equation is \(NaBr(aq)+Cl_{2}(g)\to NaCl(aq)+Br_{2}(l)\).

• Balance Br: There are 2 Br atoms on the right. So, we put a 2 in front of \(NaBr\): \(2NaBr(aq)+Cl_{2}(g)\to NaCl(aq)+Br_{2}(l)\).
• Balance Na and Cl: There are 2 Na and 2 Cl atoms on the left. So, we put a 2 in front of \(NaCl\). The balanced equation is \(2NaBr(aq)+Cl_{2}(g)\to 2NaCl(aq)+Br_{2}(l)\). This is a single - displacement reaction as one element (Cl) displaces another element (Br) from its compound.

Answer:

A. \(S(s)+O_{2}(g)\to SO_{2}(g)\); Combination (Synthesis) reaction
B. \(N_{2}(g)+3H_{2}(g)\to 2NH_{3}(g)\); Combination (Synthesis) reaction
C. \(CaCl_{2}(aq)+2AgNO_{3}(aq)\to Ca(NO_{3})_{2}(aq)+2AgCl(s)\); Double - displacement (Metathesis) reaction
D. \(2NaBr(aq)+Cl_{2}(g)\to 2NaCl(aq)+Br_{2}(l)\); Single - displacement reaction