Let's address the questions asked one by one in a clear and detailed manner:
#### 7. Which chemical equation is unbalanced?
To determine which chemical equation is unbalanced, we need to check if the number of atoms for each element is the same on both sides of the equation.
A. [tex]\(2 KClO_3 \rightarrow 2 KCl + 3 O_2\)[/tex]
- Reactants: 2 K, 2 Cl, 6 O
- Products: 2 K, 2 Cl, 6 O
This equation is balanced.
B. [tex]\(CH_4 + 2 O_2 \rightarrow CO_2 + 2 H_2O\)[/tex]
- Reactants: 1 C, 4 H, 4 O
- Products: 1 C, 4 H, 4 O
This equation is balanced.
C. [tex]\(Fe_2O_3 + CO \rightarrow 2 Fe + 2 CO_2\)[/tex]
- Reactants: 2 Fe, 3 O, 1 C
- Products: 2 Fe, 4 O, 2 C
This equation is unbalanced.
D. [tex]\(H_2CO_3 \rightarrow H_2O + CO_2\)[/tex]
- Reactants: 2 H, 1 C, 3 O
- Products: 2 H, 1 C, 3 O
This equation is balanced.
### Answer: C. [tex]\(Fe_2O_3 + CO \rightarrow 2 Fe + 2 CO_2\)[/tex]
#### 8. Which is a size-dependent property?
A size-dependent property is one that changes when the size or the amount of material changes.
A. Boiling point:
- The temperature at which a substance changes from a liquid to a gas. This is an intensive property and does not depend on the amount of substance.
B. Conductivity:
- The ability of a substance to conduct electricity or heat. This can depend on size when considering the resistance in electrical conductivity, but it’s typically considered an intensive property because the intrinsic ability to conduct remains the same regardless of size.
Checking other options, the typical correct characterizations highlight boiling point as an intensive property that doesn't usually scale with size, while conductivity can have extensive examples, but typically we consider it not as precisely size-dependent in direct terms of material quantity like mass or volume would be.
### Answer: B. Conductivity
