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 using the formula:

ext{density} = rac{ ext{mass}}{ ext{volume}}

We know:

• The density of iron = 7.9 g/cm³
• The volume of water displaced = 530 cm³ - 490 cm³ = 40 cm³

Rearranging the formula to find mass:

$$ext{mass} = ext{density} imes ext{volume}$$

The mass of the lump of iron is:

$$ext{mass} = 7.9 ext{ g/cm}^3 imes 40 ext{ cm}^3 = 316 ext{ g}$$

Rounded to 2 significant figures, the answer is 320 g.

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

• The density of wood is less than that of water, which means the wood would float and not displace an equivalent volume of water as the iron did.
• Consequently, the volume of water displaced by the wood would not reflect its actual volume, leading to incorrect mass calculations.

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

1. Equipment Required: The student will need:

   • A low voltage heater
   • A thermometer to measure water temperature
   • A measuring cylinder to measure the volume of water
   • A power supply for the heater
   • An optional stirrer to ensure even heating.

2. Setup: Place the water in a measuring cylinder. Ensure the heater is fully immersed and the thermometer is inserted to monitor temperature.

3. Measurements: Record the initial temperature of the water, and then turn on the heater. Measure a specific volume of water, and ensure to note the voltage and current used for heating.

4. Heating Process: Allow the water to heat for a predetermined time, stirring if necessary to maintain even temperature distribution.

5. Final Measurements: After a set time, measure the final temperature of the water. Using these measurements, the specific heat capacity of water can be calculated using the formula:

$$Q = mc heta$$

Where:

• Q is the heat added,
• m is the mass of the water,
• c is the specific heat capacity,
• θ is the change in temperature.

6. Average and Repeat: Repeat the experiment to find an average value.