Question 1: Define a solid, a liquid, and a gas, highlighting their main characteristics.

Answer: A solid has a fixed shape and volume, with particles tightly packed; a liquid has a fixed volume but takes the shape of its container, with particles close but able to move; a gas has neither fixed shape nor volume, with particles spread out and moving freely.

Question 2: Explain why gases are compressible whereas solids are not.

Answer: Gases are compressible because their particles are spread out with lots of space, allowing them to be pushed closer together; solids have tightly packed particles, leaving no room for compression.

Question 1: A sample of gas occupies 4.0 liters at a pressure of 1.0 atm. If the pressure is increased to 2.0 atm at constant temperature, what is the new volume of the gas? (Use Boyle’s Law: P1V1 = P2V2)

Answer: V2 = 2.0 liters

Question 2: Calculate the density of a liquid sample that has a mass of 150 grams and occupies a volume of 50 mL. Provide your answer in g/mL.

Answer: Density = 3 g/mL

Question 1: Describe a simple experiment to demonstrate the compressibility of gases. Include the variables involved and safety precautions.

Answer: One experiment involves using a syringe filled with air; by pushing the plunger, students can observe the reduction in volume, demonstrating compressibility. The independent variable is the applied pressure; the dependent variable is the volume of air. Safety precautions include avoiding over-pressurizing the syringe to prevent accidents and wearing safety goggles.

Question 1: A container holds 2 liters of helium gas at 25°C and a pressure of 1 atm. If the temperature increases to 50°C while pressure remains constant, what will be the new volume of the gas? (Use Charles' Law: V1/T1 = V2/T2, temperatures in Kelvin)

Answer: V2 = 2.08 liters

Question 2: A scientist observes that a particular substance melts at 0°C and boils at 100°C under standard atmospheric pressure. Based on these observations, identify the state changes occurring at these temperatures and explain the significance regarding phase transitions.

Answer: At 0°C, the substance changes from solid to liquid (melting), and at 100°C, it changes from liquid to gas (boiling). These temperatures are significant because they represent the melting point and boiling point under standard pressure, indicating phase transitions where the substance changes its state due to energy absorption.

Question 1: Explain how understanding the properties of gases is essential in the design of scuba diving equipment.

Answer: Knowing how gases compress and expand helps in designing scuba tanks and regulators to ensure safe breathing under different depths and pressures, preventing accidents caused by pressure changes.

Question 2: Describe a modern technological application that relies on the principles of states of matter, such as in refrigeration or air conditioning systems.

Answer: Refrigeration and air conditioning systems rely on the properties of gases and liquids to transfer heat, using the compression and expansion of refrigerants to cool or heat spaces efficiently.