Question

• please submit your answers on a separate sheet of paper. you do not need to write out the question.

1. what are the substances to the left of the arrow in a chemical equation called? what are the substances to the right of the arrow in a chemical equation called? what does the arrow itself mean?
2. for the unbalanced chemical equation: hcl(g) + o₂(g)→h₂o(g) + cl₂(g). list the reactants and. list the products and
3. what does “balancing” an equation accomplish?
4. a common lecture demonstration called “elephant’s toothpaste” demonstrates the reaction of hydrogen peroxide producing water and oxygen gas. write an unbalanced chemical equation for this process.
5. if electricity of sufficient voltage is passed into a solution of potassium iodide in water, a reaction takes place in which elemental hydrogen gas and elemental iodine are produced, leaving a solution of potassium hydroxide. write the unbalanced equation for this process.
6. silver oxide may be decomposed by strong heating into silver metal and oxygen gas. write the unbalanced chemical equation for this process.
7. balance each of the following chemical equations.

a. fecl₃(aq) + koh(aq)→fe(oh)₃(s) + kcl(aq)
b. pb(c₂h₃o₂)₂(aq) + ki(aq)→pbi₂(s) + kc₂h₃o₂(aq)
c. p₄o₁₀(s) + h₂o(l)→h₃po₄(aq)
d. li₂o(s) + h₂o(l)→lioh(aq)
e. mno₂(s) + c(s)→mn(s) + co₂(g)
f. sb(s) + cl₂(g)→sbcl₃(s)
g. ch₄(g) + h₂o(g)→co(g) + h₂(g)
h. fes(s) + hcl(aq)→fecl₂(aq) + h₂s(g)

Explanation:

Step1: Answer question 1

The substances to the left of the arrow in a chemical equation are reactants. The substances to the right are products. The arrow means "yields" or "reacts to form".

Step2: Answer question 2

For the equation $HCl(g)+O_2(g)
ightarrow H_2O(g) + Cl_2(g)$, the reactants are $HCl(g)$ and $O_2(g)$. The products are $H_2O(g)$ and $Cl_2(g)$.

Step3: Answer question 3

Balancing an equation accomplishes making the number of atoms of each element the same on both sides of the equation, which follows the law of conservation of mass.

Step4: Answer question 4

The un - balanced chemical equation for the decomposition of hydrogen peroxide is $H_2O_2
ightarrow H_2O + O_2$.

Step5: Answer question 5

The un - balanced equation for the electrolysis of potassium iodide solution is $KI(aq)+H_2O(l)
ightarrow H_2(g)+I_2(s)+KOH(aq)$.

Step6: Answer question 6

The un - balanced chemical equation for the decomposition of silver oxide is $Ag_2O
ightarrow Ag+O_2$.

Step7: Answer question 7a

The balanced equation for $FeCl_3(aq)+KOH(aq)
ightarrow Fe(OH)_3(s)+KCl(aq)$ is $FeCl_3(aq) + 3KOH(aq)
ightarrow Fe(OH)_3(s)+3KCl(aq)$.

Step8: Answer question 7b

The balanced equation for $Pb(C_2H_3O_2)_2(aq)+KI(aq)
ightarrow PbI_2(s)+KC_2H_3O_2(aq)$ is $Pb(C_2H_3O_2)_2(aq)+2KI(aq)
ightarrow PbI_2(s)+2KC_2H_3O_2(aq)$.

Step9: Answer question 7c

The balanced equation for $P_4O_{10}(s)+H_2O(l)
ightarrow H_3PO_4(aq)$ is $P_4O_{10}(s)+6H_2O(l)
ightarrow 4H_3PO_4(aq)$.

Step10: Answer question 7d

The balanced equation for $Li_2O(s)+H_2O(l)
ightarrow LiOH(aq)$ is $Li_2O(s)+H_2O(l)
ightarrow 2LiOH(aq)$.

Step11: Answer question 7e

The balanced equation for $MnO_2(s)+C(s)
ightarrow Mn(s)+CO_2(g)$ is $MnO_2(s)+C(s)
ightarrow Mn(s)+CO_2(g)$ (already balanced in terms of atoms).

Step12: Answer question 7f

The balanced equation for $Sb(s)+Cl_2(g)
ightarrow SbCl_3(s)$ is $2Sb(s)+3Cl_2(g)
ightarrow 2SbCl_3(s)$.

Step13: Answer question 7g

The balanced equation for $CH_4(g)+H_2O(g)
ightarrow CO(g)+H_2(g)$ is $CH_4(g)+H_2O(g)
ightarrow CO(g)+3H_2(g)$.

Step14: Answer question 7h

The balanced equation for $FeS(s)+HCl(aq)
ightarrow FeCl_2(aq)+H_2S(g)$ is $FeS(s)+2HCl(aq)
ightarrow FeCl_2(aq)+H_2S(g)$.

Answer:

1. Reactants; Products; Yields or reacts to form
2. $HCl(g)$, $O_2(g)$; $H_2O(g)$, $Cl_2(g)$
3. Makes the number of atoms of each element the same on both sides of the equation
4. $H_2O_2

ightarrow H_2O + O_2$

1. $KI(aq)+H_2O(l)

ightarrow H_2(g)+I_2(s)+KOH(aq)$

1. $Ag_2O

ightarrow Ag+O_2$
7a. $FeCl_3(aq) + 3KOH(aq)
ightarrow Fe(OH)_3(s)+3KCl(aq)$
7b. $Pb(C_2H_3O_2)_2(aq)+2KI(aq)
ightarrow PbI_2(s)+2KC_2H_3O_2(aq)$
7c. $P_4O_{10}(s)+6H_2O(l)
ightarrow 4H_3PO_4(aq)$
7d. $Li_2O(s)+H_2O(l)
ightarrow 2LiOH(aq)$
7e. $MnO_2(s)+C(s)
ightarrow Mn(s)+CO_2(g)$
7f. $2Sb(s)+3Cl_2(g)
ightarrow 2SbCl_3(s)$
7g. $CH_4(g)+H_2O(g)
ightarrow CO(g)+3H_2(g)$
7h. $FeS(s)+2HCl(aq)
ightarrow FeCl_2(aq)+H_2S(g)$