Identify and explain the function of parts of a thermos flask and a filtration apparatus.

Here is the solution to question 1:

c) i. Identify the figure above.
The figure above is a thermos flask (or vacuum flask).

c) ii. Name the parts labelled I, II, III, IV and V.

• I: Stopper (or lid)
• II: Vacuum
• III: Silvered surface
• IV: Inner glass wall (or inner bottle)
• V: Insulating support (or cork support)

c) iii. How does the device minimize heat loss or gain through (α) conduction? (β) convection? (γ) radiation?

• (α) Conduction: Heat loss by conduction is minimized by the vacuum (II) which is a poor conductor, and by the stopper (I) and insulating support (V) which are made of poor heat conductors.
• (β) Convection: Heat loss by convection is minimized by the vacuum (II) which prevents the movement of air particles, and by the stopper (I) which prevents air from entering or leaving the flask.
• (γ) Radiation: Heat loss by radiation is minimized by the silvered surfaces (III) which reflect infrared radiation.

c) iv. State one use of the thermos flask.
A thermos flask is used to keep hot liquids hot or cold liquids cold for an extended period.

d) i. Name each of the parts labelled I, II, III, IV and V.

• I: Filter funnel
• II: Evaporating dish (or watch glass)
• III: Bunsen burner (or heat source)
• IV: Condenser
• V: Beaker (or receiving flask)

d) ii. Name the separation method represented by each diagram.

• A: Filtration
• B: Evaporation
• C: Distillation

d) iii. Which of the set-ups is used to obtain clear water from muddy water?
Set-up A (Filtration) is used to obtain clear water from muddy water by separating insoluble mud particles from water.

d) iv. Which of the set-ups is used to obtain salt from salt solution?
Set-up B (Evaporation) is used to obtain salt from a salt solution by evaporating the water.