Okay, bazuunelson, let's tackle these questions. Question 13: Calculate the mass of copper metal that was obtained. Step 1: Write the half-reaction for copper deposition. During electrolysis, copper(II) ions gain electrons to form solid copper. $$Cu^{2+}(aq) + 2e^- \to Cu(s)$$ This reaction shows that $2 \text{ moles of electrons}$ are required to deposit $1 \text{ mole of Cu}$. Step 2: Calculate the moles of electrons transferred. Given charge $Q = 144,750 \text{ C}$ and Faraday's constant $F = 96,500 \text{ C/mol e}^-$. $$\text{Moles of electrons} = \frac{Q}{F}$$ $$\text{Moles of electrons} = \frac{144750 \text{ C}}{96500 \text{ C/mol e}^-}$$ $$\text{Moles of electrons} = 1.5 \text{ mol e}^-$$ Step 3: Calculate the moles of copper deposited. From the half-reaction, $1 \text{ mole of Cu}$ requires $2 \text{ moles of electrons}$. $$\text{Moles of Cu} = \frac{\text{Moles of electrons}}{2}$$ $$\text{Moles of Cu} = \frac{1.5 \text{ mol}}{2}$$ $$\text{Moles of Cu} = 0.75 \text{ mol}$$ Step 4: Calculate the mass of copper deposited. Given molar mass of Cu = $64 \text{ g/mol}$. $$\text{Mass of Cu} = \text{Moles of Cu} \times \text{Molar mass of Cu}$$ $$\text{Mass of Cu} = 0.75 \text{ mol} \times 64 \text{ g/mol}$$ $$\text{Mass of Cu} = 48 \text{ g}$$ The mass of copper metal obtained is $\boxed{\text{48 g}}$. Question 14: State one physical and one chemical difference between Na₂O₂ and Na₂O. Physical difference: Sodium peroxide ($Na_2O_2$) is a pale yellow solid, while sodium oxide ($Na_2O$) is a white solid. Chemical difference: Sodium peroxide ($Na_2O_2$) reacts with water to produce hydrogen peroxide ($H_2O_2$) and sodium hydroxide, showing its peroxidic nature. $$Na_2O_2(s) + 2H_2O(l) \to 2NaOH(aq) + H_2O_2(aq)$$ Sodium oxide ($Na_2O$) reacts with water to produce only sodium hydroxide, as it is a basic oxide. $$Na_2O(s) + H_2O(l) \to 2NaOH(aq)$$ Question 15: The question states "The diagram below shows an electrochemical cell:". However, the diagram itself is not visible in the image provided. Therefore, this question cannot be answered without the diagram. Last free one today — make it count tomorrow, or type /upgrade for unlimited.