Question

Describe an activity to determine the boiling point of water and melting point of ice.

June 22, 2024

Answer

Determination of boiling point of water:

▪ In a beaker take some water and insert a thermometer in it with the help of a clamp

▪ Put the beaker on a tripod stand and heat the apparatus with the help of kerosene burner slowly

▪ Observe what happens to water.

▪ You will observe a steady stream of bubbles. This temperature is the boiling point of water.

Determination of melting point of ice:

▪ Take crushed ice in a beaker and insert a thermometer in the beaker by hanging it from the clamp of the stand in such ay that the bulb of the thermometer is completely inside the ice.

▪ Wait for some time and keep recording the temperature after small intervals of time.

▪ Note down the temperature when ice just starts melting.

▪ Let the bulb of the thermometer remain in mixture of ice and water for some more time and keep recording the temperature. This temperature is the melting point of ice.

💡 Some Related Questions

One day, Reena was helping her mother in household work. Suddenly a bottle from her mother’s cosmetics broke and the liquid fell on her hand. She got worried and asked her mother why she felt cold. Her mother explained the reason to her which satisfied her. Answer the following questions based on above passage. (𝒊) Can you guess the liquid that felt on Reena’s hand? (𝒊𝒊) Why did she feel cold when liquid fall on her hand? (𝒊𝒊𝒊) What are the values shown by Reena’s mother?

Mrs. Khanna was making breakfast in kitchen. For this purpose she was heating water in a pan. In the meantime, her 12 years old son, Pappu entered the kitchen and saw the water vapour coming out from the pan. Pretend yourself to be Mrs. Khanna and answer the following questions: (𝒊) What is the process going on in the pan? (𝒊𝒊) Why was this process occurring? (𝒊𝒊𝒊) Give one way by which Pappu can relate this phenomenon with his everyday life. (𝒊𝒗) What values are shown by Pappu?

Water as ice has a cooling effect, whereas water as steam may cause severe burns. Explain these observations.

The temperature-time graph given alongside shows the heating curve for pure wax. From the graph answer the following: (a) What is the physical state of the substance at the point A, B, C and D? (b) What is the melting point of the substance? (c) What is the boiling point? (d) Which portions of the graph indicates that change to state is taking place? (e) Name the terms used for heat absorbed during change of states involved in above process.

Name the changes in the terms of processes P, Q, R and S. (b) Which of the changes are exothermic and endothermic?

You are given the following substances with their melting and bowling points. Identify the physical status of X, Y and Z at room temperature (30°C).

Substance Melting point(°C) Boiling point(°C)

X -219 -183

Y 119 445

Z -15 78

A sample of water under study was found to boil at 102°C at normal temperature and pressure. Is the water pure? Will this water freeze at 0°C Comment.

A small volume of water in a kettle can fill a kitchen with steam’. Explain why.

The diagram below shows burning of an oil lamp. Draw the arrangement of particles of position ‘X’ and ‘Y’ when the lamp is burning.

Comment on the following statements Evaporation causes cooling. (b) Rate of evaporation of an aqueous solution decreases with increase in humidity. (c) Sponge though compressible is a solid. (d) Ice is solid at 0°C, while water is liquid at room temperature. (e) Sugar crystals dissolve faster in hot water than cold water.