7. équilibre les réactions suivantes:
a) $ \ce{c7h_{12}(l) + o_{2}(g) - co_{2}(g) + h_{2}o(g)} $
b) $ \ce{naoh(aq) + cucl_{2}(aq) - nacl(aq) + cu(oh)_{2}(s)} $
c) $ \ce{alf_{3}(aq) + li_{2}so_{4}(aq) - lif(aq) + al_{2}(so_{4})_{3}(s)} $
d) $ \ce{c_{4}h_{8}(l) + o_{2}(g) - co_{2}(g) + h_{2}o(g)} $
8. trace la structure des molécules organiques suivantes à partir de leurs noms uicpa.
a) hex-3-yne
b) 2,4-diméthyl-4-éthylheptane
c) 3-éthyl-4-propyloctane
d) but-2-ène
e) cyclopropane
f) cyclopentène

Question

7. équilibre les réactions suivantes:
a) $ \ce{c7h_{12}(l) + o_{2}(g) -> co_{2}(g) + h_{2}o(g)} $
b) $ \ce{naoh(aq) + cucl_{2}(aq) -> nacl(aq) + cu(oh)_{2}(s)} $
c) $ \ce{alf_{3}(aq) + li_{2}so_{4}(aq) -> lif(aq) + al_{2}(so_{4})_{3}(s)} $
d) $ \ce{c_{4}h_{8}(l) + o_{2}(g) -> co_{2}(g) + h_{2}o(g)} $
8. trace la structure des molécules organiques suivantes à partir de leurs noms uicpa.
a) hex-3-yne
b) 2,4-diméthyl-4-éthylheptane
c) 3-éthyl-4-propyloctane
d) but-2-ène
e) cyclopropane
f) cyclopentène

Accepted Answer

### For Question 7 (Balancing Chemical Reactions)
# Explanation:
## Step1: Balance C then H then O
For reaction a): $C_7H_{12}(l) + O_2(g)
ightarrow CO_2(g) + H_2O(g)$
1. Balance C: $C_7H_{12} + O_2
ightarrow 7CO_2 + H_2O$
2. Balance H: $C_7H_{12} + O_2
ightarrow 7CO_2 + 6H_2O$
3. Balance O: Total O on right = $14 + 6 = 20$, so $O_2$ coefficient = 10
Final: $C_7H_{12}(l) + 10O_2(g)
ightarrow 7CO_2(g) + 6H_2O(g)$

## Step2: Balance Cu, Cl, Na, OH
For reaction b): $NaOH(aq) + CuCl_2(aq)
ightarrow NaCl(aq) + Cu(OH)_2(s)$
1. Balance Cu: $NaOH + CuCl_2
ightarrow NaCl + Cu(OH)_2$
2. Balance OH: Add 2 to NaOH: $2NaOH + CuCl_2
ightarrow NaCl + Cu(OH)_2$
3. Balance Na/Cl: Add 2 to NaCl: $2NaOH(aq) + CuCl_2(aq)
ightarrow 2NaCl(aq) + Cu(OH)_2(s)$

## Step3: Balance Al, F, Li, $SO_4$
For reaction c): $AlF_3(aq) + Li_2SO_4(aq)
ightarrow LiF(aq) + Al_2(SO_4)_3(s)$
1. Balance Al: $2AlF_3 + Li_2SO_4
ightarrow LiF + Al_2(SO_4)_3$
2. Balance $SO_4$: Add 3 to $Li_2SO_4$: $2AlF_3 + 3Li_2SO_4
ightarrow LiF + Al_2(SO_4)_3$
3. Balance Li/F: Add 6 to LiF: $2AlF_3(aq) + 3Li_2SO_4(aq)
ightarrow 6LiF(aq) + Al_2(SO_4)_3(s)$

## Step4: Balance C then H then O
For reaction d): $C_8H_{14}(l) + O_2(g)
ightarrow CO_2(g) + H_2O(g)$
1. Balance C: $C_8H_{14} + O_2
ightarrow 8CO_2 + H_2O$
2. Balance H: $C_8H_{14} + O_2
ightarrow 8CO_2 + 7H_2O$
3. Balance O: Total O on right = $16 + 7 = 23$, so $O_2$ coefficient = $\frac{23}{2}$, multiply all by 2:
Final: $2C_8H_{14}(l) + 23O_2(g)
ightarrow 16CO_2(g) + 14H_2O(g)$

# Answer:
a) $\boldsymbol{C_7H_{12}(l) + 10O_2(g)
ightarrow 7CO_2(g) + 6H_2O(g)}$
b) $\boldsymbol{2NaOH(aq) + CuCl_2(aq)
ightarrow 2NaCl(aq) + Cu(OH)_2(s)}$
c) $\boldsymbol{2AlF_3(aq) + 3Li_2SO_4(aq)
ightarrow 6LiF(aq) + Al_2(SO_4)_3(s)}$
d) $\boldsymbol{2C_8H_{14}(l) + 23O_2(g)
ightarrow 16CO_2(g) + 14H_2O(g)}$

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### For Question 8 (Drawing Organic Structures, simplified skeletal/condensed form)
# Brief Explanations:
Each structure is drawn following IUPAC rules: identify parent chain, add substituents, place double/triple bonds at the correct position.
# Answer:
a) **hex-3-yne**: $CH_3CH_2C \equiv CCH_2CH_3$ (6-carbon chain, triple bond at C3)
b) **2,4-dimethyl-4-ethylheptane**: $CH_3CH(CH_3)CH_2C(CH_3)(CH_2CH_3)CH_2CH_2CH_3$ (7-carbon parent chain, methyl at C2, methyl/ethyl at C4)
c) **cyclopropane**: 3-carbon ring with single bonds between each C: $	riangle$
d) **but-2-ène**: $CH_3CH=CHCH_3$ (4-carbon chain, double bond at C2)
e) **3-éthyl-4-propyloctane**: $CH_3CH_2CH(CH_2CH_3)CH(CH_2CH_2CH_3)CH_2CH_2CH_2CH_3$ (8-carbon parent chain, ethyl at C3, propyl at C4)
f) **cyclopentène**: 5-carbon ring with one double bond: $\bigcirc^=$ (skeletal ring with a double bond between two adjacent carbons)

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QUESTION IMAGE

Question

Explanation:

For Question 7 (Balancing Chemical Reactions)

Step1: Balance C then H then O

Step2: Balance Cu, Cl, Na, OH

Step3: Balance Al, F, Li, $SO_4$

Step4: Balance C then H then O

Answer:

For Question 8 (Drawing Organic Structures, simplified skeletal/condensed form)