CHEMN-134541: 121 Jadual 1 menunjukkan nombor prot

D

Key Concept

Insolubility in water of compounds formed by certain elements

Explanation

The compound formed by elements Y (with proton number 6) and Z (with proton number 17) is typically insoluble in water due to the nature of the ionic bonds and the solubility rules for salts.

D

Key Concept

Increasing temperature increases reaction rates.

Explanation

Increasing the temperature of hydrochloric acid provides more energy to the reacting particles, which increases the frequency and energy of collisions, leading to a higher rate of hydrogen production.

B

Key Concept

Energy profile diagrams show the energy changes during a chemical reaction.

Explanation

In the energy profile diagram, the value of X represents the energy difference between the reactants and products. Since the peak is at 180 kJ mol⁻¹ and the trough is at 80 kJ mol⁻¹, the difference is 100 kJ mol⁻¹, which corresponds to option B.

B

Key Concept

Average rate of reaction calculation

Explanation

The average rate of reaction is calculated using the formula:

\text{Average Rate} = \frac{\text{Change in amount of reactant}}{\text{Time}}

In this case, the change in moles of zinc is

0.20 \, \text{mol} - 0.05 \, \text{mol} = 0.15 \, \text{mol}

over 5 minutes. Converting moles to grams using the relative atomic mass of zinc (65 g/mol), we find:

\text{Mass of zinc reacted} = 0.15 \, \text{mol} \times 65 \, \text{g/mol} = 9.75 \, \text{g}

Thus, the average rate is:

\text{Average Rate} = \frac{9.75 \, \text{g}}{5 \, \text{min}} = 1.95 \, \text{g/min}

This corresponds to option B.

AskSia

Plus