Provide answers for the extraction of zinc and sequence of copper reactions questions, including chemical…

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Provide answers for the extraction of zinc and sequence of copper reactions questions, including chemical equations and observations.

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here are the solutions to the questions.

Question 9: Extraction of Zinc

a) The process used in step 2 to concentrate the ore is froth flotation (or gravity separation).

\boxed{\text{Froth flotation}}

b) The reaction that takes place in step 3 is the thermal decomposition of zinc carbonate to zinc oxide and carbon dioxide.

\boxed{\text{ZnCO}_3(\text{s}) \xrightarrow{\text{heat}} \text{ZnO}(\text{s}) + \text{CO}_2(\text{g})}

c) One use of zinc other than galvanizing is in the production of alloys (e.g., brass) or dry cell batteries.

\boxed{\text{Alloys (e.g., brass)}}

Question 10: Sequence of Copper Reactions

a) In step 1, excess 3M nitric acid was added to 0.5g of copper powder.

(i) Two observations made were:
- The reddish-brown copper powder dissolves, and the solution turns blue.
- A brown gas is evolved.
(ii) Dilute hydrochloric acid cannot be used in step 1 because copper is less reactive than hydrogen and therefore cannot displace hydrogen from hydrochloric acid. Hydrochloric acid is also a non-oxidizing acid.
(iii) I. The equation for the reaction in step 1 is: $\boxed{\text{Cu}(\text{s}) + 4\text{HNO}_3(\text{aq}) \to \text{Cu(NO}_3)_2(\text{aq}) + 2\text{NO}_2(\text{g}) + 2\text{H}_2\text{O}(\text{l})}$
(iii) II. Calculate the volume of 3M nitric acid needed.

Calculate moles of copper.

$$
\text{Moles of Cu} = \frac{\text{Mass}}{\text{Molar mass}} = \frac{0.5 \text{ g}}{63.5 \text{ g/mol}} \approx 0.007874 \text{ mol}
$$

Use stoichiometry to find moles of nitric acid.
From the equation, $1 \text{ mol Cu}$ reacts with $4 \text{ mol HNO}_3$ . $\text{Moles of HNO}_3 = 4 \times \text{Moles of Cu} = 4 \times 0.007874 \text{ mol} \approx 0.031496 \text{ mol}$

Calculate the volume of nitric acid.

$$
\text{Volume of HNO}_3 = \frac{\text{Moles}}{\text{Concentration}} = \frac{0.031496 \text{ mol}}{3 \text{ mol/dm}^3} \approx 0.010499 \text{ dm}^3
$$
Converting to $\text{cm}^3$:
$$
\text{Volume of HNO}_3 = 0.010499 \text{ dm}^3 \times 1000 \text{ cm}^3/\text{dm}^3 \approx 10.5 \text{ cm}^3
$$
$$
\boxed{10.5 \text{ cm}^3}
$$

b) The names of the types of reactions that took place in steps 4 and 5 are:

$\text{CuO}(\text{s}) + 2\text{HCl}(\text{aq}) \to \text{CuCl}_2(\text{aq}) + \text{H}_2\text{O}(\text{l})$ is an acid-base reaction (or neutralization).
$\text{Cu}^{2+}(\text{aq}) + \text{Metal Q}(\text{s}) \to \text{Cu}(\text{s}) + \text{Q}^{2+}(\text{aq})$ is a displacement reaction.
$\boxed{\text{Step 4: Acid-base reaction, Step 5: Displacement reaction}}$
c) Apart from good conductivity of electricity, two other properties of copper that make it suitable for the electrical industry are:
- Ductility (can be drawn into wires).
- Malleability (can be hammered into sheets).
Question 11: Investigation of Temperature Changes

a) Two factors that must be kept constant in this experiment are:
- Initial temperature of the acid and sodium hydroxide solutions.
- Concentration of the acid and sodium hydroxide solutions.
- Volume of the acid.
b) The use of a polystyrene cup will reduce heat loss to the surroundings because polystyrene is a good thermal insulator. This will lead to a more accurate measurement of the temperature change.

Question 12: Molar Heat of Displacement and Energy Level Diagram

a) The molar heat of displacement is the enthalpy change when one mole of a metal is displaced from its salt solution by a more reactive metal.

b) The reaction $\text{Z}^{2+}(\text{aq}) + \text{Y}(\text{s}) \to \text{Z}(\text{s}) + \text{Y}^{2+}(\text{aq})$ has $\Delta \text{H} = -\text{ve}$ , meaning it is an exothermic reaction.
The energy level diagram for an exothermic reaction shows the products at a lower energy level than the reactants.
\begin{tikzpicture} \draw[->] (0,0) -- (0,4) node[above] {Energy}; \draw[->] (0,0) -- (4,0) node[right] {Reaction progress}; \draw[thick] (0.5,3.5) -- (1.5,3.5) node[right] {Reactants: $\text{Z}^{2+}(\text{aq}) + \text{Y}(\text{s})$}; \draw[thick] (2.5,1.5) -- (3.5,1.5) node[right] {Products: $\text{Z}(\text{s}) + \text{Y}^{2+}(\text{aq})$}; \draw[<->, dashed] (1.5,3.5) -- (2.5,1.5) node[midway, right] {$\Delta \text{H} = -\text{ve}$}; \end{tikzpicture}

Provide answers for the extraction of zinc and sequence of copper reactions questions, including chemical equations and observations.

Step-by-step solution

Calculate moles of copper.

Use stoichiometry to find moles of nitric acid.

Calculate the volume of nitric acid.

$\text{CuO}(\text{s}) + 2\text{HCl}(\text{aq}) \to \text{CuCl}_2(\text{aq}) + \text{H}_2\text{O}(\text{l})$ is an acid-base reaction (or neutralization).

$\text{Cu}^{2+}(\text{aq}) + \text{Metal Q}(\text{s}) \to \text{Cu}(\text{s}) + \text{Q}^{2+}(\text{aq})$ is a displacement reaction.

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More Chemistry Questions

Provide answers for the extraction of zinc and sequence of copper reactions questions, including chemical equations and observations.

Step-by-step solution

Calculate moles of copper.

Use stoichiometry to find moles of nitric acid.

Calculate the volume of nitric acid.

CuO(s)+2HCl(aq)→CuCl2(aq)+H2O(l)\text{CuO}(\text{s}) + 2\text{HCl}(\text{aq}) \to \text{CuCl}_2(\text{aq}) + \text{H}_2\text{O}(\text{l})CuO(s)+2HCl(aq)→CuCl2​(aq)+H2​O(l) is an acid-base reaction (or neutralization).

Cu2+(aq)+Metal Q(s)→Cu(s)+Q2+(aq)\text{Cu}^{2+}(\text{aq}) + \text{Metal Q}(\text{s}) \to \text{Cu}(\text{s}) + \text{Q}^{2+}(\text{aq})Cu2+(aq)+Metal Q(s)→Cu(s)+Q2+(aq) is a displacement reaction.

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More Chemistry Questions

$\text{CuO}(\text{s}) + 2\text{HCl}(\text{aq}) \to \text{CuCl}_2(\text{aq}) + \text{H}_2\text{O}(\text{l})$ is an acid-base reaction (or neutralization).

$\text{Cu}^{2+}(\text{aq}) + \text{Metal Q}(\text{s}) \to \text{Cu}(\text{s}) + \text{Q}^{2+}(\text{aq})$ is a displacement reaction.