When water boils and turns into steam, there are changes in the arrangement of particles and the density - Edexcel - GCSE Physics Combined Science - Question 6 - 2022 - Paper 1

To find the mass of the lump of iron, we can use the formula:

$$ext{density} = \frac{\text{mass}}{\text{volume}}$$

Rearranging the formula gives:

$$\text{mass} = \text{density} \times \text{volume}$$

Substituting the known values:

• Density of iron = 7.9 g/cm³
• Volume = 530 cm³ - 490 cm³ = 40 cm³

Thus:

$$\text{mass} = 7.9\, \mathrm{g/cm^3} \times 40\, \mathrm{cm^3} = 316\, g$$

Rounding to two significant figures, the mass of the lump of iron is 320 g.

The method used in part (b) cannot be used for the piece of wood because:

1. The density of wood is less than that of water, therefore it would float rather than submerge completely.
2. Since the wood does not displace an equivalent amount of water when it floats, the volume measurement for the wood would be incorrect, leading to an inaccurate mass calculation.

To determine the specific heat capacity of water, the student should follow these steps:

1. Equipment Needed:

   • Low voltage heater
   • Measuring cylinder for water
   • Thermometer to measure the temperature
   • Power supply to operate the heater
   • Stopwatch/clock to time the heating

2. Method:

   • Measure a known volume of water using the measuring cylinder and record the initial temperature.
   • Place the heater fully submerged in the water to ensure even heating.
   • Begin heating the water, measuring the temperature at regular intervals.
   • Stir the water gently while heating to maintain uniform temperature throughout.
   • Stop heating once the water reaches a certain maximum temperature and record the final temperature.

3. Measurements Needed:

   • Mass of the water (use the density of water for conversion if needed).
   • Change in temperature (final - initial).
   • Power input to the heater, which can be determined from voltage and current readings.

4. Data Collection:

   • Use the formula:
   $$Q = m \cdot c \cdot \Delta T$$

   where Q is the energy supplied, m is the mass of water, c is the specific heat capacity, and ΔT is the change in temperature.

   • Calculate c based on the collected data.

5. Diagram (if applicable):

   • A labeled diagram can help visualize the setup, including the heater, measuring cylinder, and thermometer.