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 first need to determine the volume of the displaced water:

Volume of water displaced = Water level after lowering iron - Original water level = 530 cm³ - 490 cm³ = 40 cm³.

Using the density formula:

We rearrange it to find mass:

Substituting the known values:

Rounding to two significant figures gives:

Answer: 320 g.

The method from part (b) cannot be used because the density of the wood is less than that of water, causing it to float. Therefore, it would not displace a volume of water equivalent to its mass, leading to an incorrect measurement.

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

1. Equipment Needed:

   • Low voltage heater
   • Thermometer
   • Measuring cylinder/balance (for mass of water)
   • Power supply
   • Stirrer
   • Stopwatch

2. Measurements Needed:

   • Measure the initial temperature of the water.
   • Measure the mass of the water used.
   • Record the voltage and current during heating.

3. Procedure:

   • Ensure the heater is fully submerged in water.
   • Start the heater and stir the water continuously to ensure even heating.
   • Measure the temperature at regular intervals until a significant change is observed.
   • Stop the heater after a set time, recording the final temperature.
   • Use the formula:
   $$Q = m imes c imes riangle T$$

   where Q is heat energy supplied, m is mass, c is specific heat capacity, and $riangle T$ is the change in temperature.

4. Calculations:

   • Calculate the total energy supplied using the voltage and current readings:

   $ext{Energy} = ext{Voltage} imes ext{Current} imes ext{Time}$

   • Rearrange to find the specific heat capacity (c).

5. Repeat and Average:

   • Repeat the experiment multiple times for accuracy and take an average of the results.

The answer may be aided by a well-labeled diagram illustrating the setup.