8. Fizzy drinks are made by adding carbon dioxide gas, preservative, colouring and flavouring to water - Scottish Highers Chemistry - Question 8 - 2023

To illustrate the effect of temperature increase on the yield of carbon dioxide:

• The graph should show a decrease in yield as temperature increases, indicating that as the temperature increases, the yield decreases.

Firstly, calculate the number of moles of sorbic acid:

• Moles of sorbic acid =
  [ \frac{7 \text{g}}{112 \text{g/mol}} = 0.0625 \text{ mol} ]

Next, calculate the moles of potassium hydroxide:

• Volume of KOH solution = 250 cm³ = 0.250 dm³
• Moles of KOH = Concentration × Volume =
  [ 0.025 \text{ mol/dm}^3 \times 0.250 ext{ dm}^3 = 0.00625\text{ mol} ]

Since there are fewer moles of KOH than sorbic acid, sorbic acid is the limiting reactant.

To find the moles of ammonium ferric citrate needed:

• First, convert percentage concentration to mass in 330 cm³: [ 0.002% \text{ of } 330 ext{ g} = 0.0066 ext{ g} ]

• Now convert mass to moles: [ ext{Moles} = \frac{0.0066 ext{ g}}{261.8 ext{ g/mol}} = 2.52 \times 10^{-5} ext{ mol} ]

Essential oils are typically volatile and have distinctive aromas.

The type of compound formed is a terpenoid.

The structural formula for isoprene is as follows:

      H   H
       \ /  
        C
       / \  
      H   C   H
         / \ / 
        C   C
          |   |
          H   H

A zingiberene molecule is composed of three isoprene units.

Product X is shogaol.

The two functional groups are:

1. Hydroxyl (-OH)
2. Carbonyl (-C=O)