Physics Grade 10 Gas laws Isoprocesses Investigation sheet mark scheme

Question

Answer

Mark

Additional Guidance

1

a)

b)

c)

Dependent: volume

Independent: temperature

All variables, aside the dependent and independent variable, and experimental conditions must be kept constant to draw valid conclusions.

The piston must be frictionless

1

1

1

[3]

2

a)

b)

c)

d)

e)

axes labelled with V/mL on y axis and t/^oC on x axis

plots occupying at least half the grid  

all plots correct to Ѕ small square

good line judgement and quality of line (line of best fit)

triangle method used and shown

using at least half of line

calculation of G correct (G ≈ 0.4)

Correct value of b from their graph and correct equation (b ≈ 114)

y = 0 in equation and solves correctly

t ≈ – 280 ^oC

Absolute zero

1

1

1

1

1

1

1

1

2

1

[11]

See graph below

No units are required in answers b) and c)

Allow ± 6 ^oC

3

a)

b) i)

ii)

c)

Measure the (inner) diameter of the tube.

Attach a ruler vertically to the test tube and measure the height of air as it expands

V = π(D²/4)h

Temperature increases faster, so air expands faster; Difficult to read accurate matching values of volume and temperature

The experiment may take too long

Two of the following

wear goggles, lab coat and gloves to handle hot equipment

1

1

1

1

1

1

[6]

Accept any other reasonable method as long as it is correctly described