States of matter flashcards

All 20 cards

1. Card 1

   Explain why a gas can change directly to a solid, even though it's not always shown in simple state change diagrams.

   A gas can change directly to a solid through a process called deposition or desublimation. This occurs when gas particles lose enough kinetic energy to form a solid structure without first passing through a liquid phase, typically under specific temperature and pressure conditions.

2. Card 2

   Why do changes 1 and 3 (condensation and freezing, respectively) involve particles moving closer together?

   Changes like condensation (gas to liquid) and freezing (liquid to solid) involve particles moving closer together because energy is removed from the substance. As particles lose kinetic energy, their movement slows down, allowing intermolecular forces to pull them into more ordered, compact arrangements.

3. Card 3

   Explain why changes 2 and 4 (boiling/evaporation and melting, respectively) involve particles moving further apart.

   Changes such as boiling/evaporation (liquid to gas) and melting (solid to liquid) involve particles moving further apart because energy is supplied to the substance. This added energy increases the kinetic energy of the particles, enabling them to overcome intermolecular forces and move more freely, leading to increased separation.

4. Card 4

   Why do changes 3, 4, and 5 (freezing, melting, and condensation/evaporation) not all involve the release of energy?

   Changes 3 (freezing) and 5 (condensation) involve the release of energy as particles come closer together and form stronger bonds. However, change 4 (melting) involves the absorption of energy to break bonds and allow particles to move further apart, not the release of energy.

5. Card 5

   In a diffusion experiment with ammonia and hydrogen chloride gases, why does a white deposit of ammonium chloride form closer to the hydrogen chloride source?

   Ammonium chloride forms closer to the hydrogen chloride source because ammonia gas (NH3, Mr=17) has a lower relative molecular mass than hydrogen chloride gas (HCl, Mr=36.5). According to Graham's Law of Diffusion, lighter molecules diffuse faster, so ammonia travels a greater distance in the same amount of time before reacting with HCl.

6. Card 6

   Why does the smell of bromine eventually spread across a room after drops are placed on a table-top?

   The smell of bromine spreads due to diffusion. After evaporation, bromine particles collide with air particles, move in a random way, and spread out to occupy the total available space. This continuous random motion and collision lead to the uniform distribution of bromine particles throughout the room.

7. Card 7

   DEFINITION: Define diffusion and explain why it provides strong evidence for the particle theory of matter.

   Diffusion is the net movement of particles from an area of higher concentration to an area of lower concentration, resulting from their random motion. It provides strong evidence for the particle theory of matter because it demonstrates that particles are in constant, random motion and that there are spaces between them, allowing them to spread out and mix.

8. Card 8

   Explain why propane (C3H8) and carbon dioxide (CO2) diffuse at the same rate at room temperature and pressure.

   Propane (C3H8) and carbon dioxide (CO2) diffuse at the same rate because they have the same relative molecular mass (Mr). Propane's Mr is 3(12) + 8(1) = 44, and carbon dioxide's Mr is 12 + 2(16) = 44. The rate of diffusion is inversely proportional to the square root of the relative molecular mass, so identical molecular masses result in identical diffusion rates.

9. Card 9

   Why do brown fumes of bromine vapour slowly spread through a covered gas jar when a drop of liquid bromine is placed at the bottom?

   This phenomenon occurs because bromine molecules and the molecules in the air are always moving around randomly. The bromine molecules, initially concentrated at the bottom, collide with air molecules and gradually spread out due to their constant motion until they are uniformly distributed throughout the gas jar.

10. Card 10

    In a diffusion experiment with a porous pot, which gas (CO2, Cl2, CH4, or NO2) in the beaker will cause the water level at Y to rise, and why?

    Methane (CH4, Mr=16) will cause the water level at Y to rise. This is because methane has a lower relative molecular mass than air (average Mr approx. 29). Lighter methane molecules will diffuse into the porous pot faster than the heavier air molecules diffuse out, increasing the pressure inside the pot and pushing the water level down in the pot and up at Y.

11. Card 11

    If air is cooled, water condenses first. What is the next substance to condense from the given list (argon, carbon dioxide, nitrogen, oxygen) and why?

    The next substance to condense after water would be oxygen (boiling point -183°C). Condensation occurs when a gas is cooled to its boiling point. Among the given options, oxygen has the highest boiling point after water, meaning it will condense at a relatively higher temperature than argon, nitrogen, or carbon dioxide (which sublimes at -78°C).

12. Card 12

    Describe the arrangement and movement of molecules in a very dilute sugar solution at room temperature.

    In a very dilute sugar solution at room temperature, the water molecules are close together and moving at random, characteristic of a liquid. The sugar molecules are also widely separated and moving at random within the water, as they are dissolved and dispersed throughout the solvent.

13. Card 13

    Explain why energy is released when a substance changes from a liquid to a solid state.

    When a substance changes from liquid to solid (freezes), its particles lose kinetic energy and arrange themselves into a more ordered, fixed structure. This reduction in the internal energy of the particles is released to the surroundings, typically as heat, as stronger intermolecular forces are established.

14. Card 14

    Why does neon gas (Ne) diffuse faster than carbon dioxide gas (CO2)?

    Neon gas diffuses faster than carbon dioxide gas because neon atoms have a lower mass (Mr=20) compared to carbon dioxide molecules (Mr=44). According to Graham's Law of Diffusion, gases with lower relative molecular masses diffuse at a faster rate.

15. Card 15

    DEFINITION: Describe the arrangement of particles in a gas.

    In a gas, particles are widely separated and move rapidly and randomly in all directions. They have no fixed positions and collide frequently with each other and the walls of their container, filling any available volume.

16. Card 16

    Which gas diffuses at the same rate as nitrogen gas (N2), and why?

    Carbon monoxide (CO) diffuses at the same rate as nitrogen gas (N2). Nitrogen (N2) has a relative molecular mass of 28 (2 x 14), and carbon monoxide (CO) also has a relative molecular mass of 28 (12 + 16). Gases with the same relative molecular mass diffuse at the same rate under the same conditions.

17. Card 17

    DEFINITION: What property uniquely indicates that a liquid is pure?

    The property that uniquely indicates a liquid is pure is that it boils at a fixed temperature at a given pressure. Impurities would cause the boiling point to be elevated and occur over a range of temperatures rather than at a single, precise point.

18. Card 18

    If liquid air is cooled, and water condenses first, which elements (argon, helium, neon, nitrogen, oxygen) would be gaseous at -190°C?

    At -190°C, helium (boiling point -269°C) and neon (boiling point -246°C) would still be gaseous. Argon (-186°C), nitrogen (-198°C), and oxygen (-183°C) would have condensed into liquids or solids as their boiling points are higher than -190°C.

19. Card 19

    Why does an inflated balloon filled with methane (CH4) go down quicker than balloons filled with carbon dioxide (CO2), nitrogen (N2), or oxygen (O2) at the same temperature and pressure?

    The balloon filled with methane (CH4) would go down quickest because methane has the lowest relative molecular mass (Mr=16) compared to nitrogen (Mr=28), oxygen (Mr=32), and carbon dioxide (Mr=44). Lighter gas molecules diffuse through the rubber faster than heavier ones.

20. Card 20

    When a gas jar of nitrogen dioxide (dark brown, more dense than air) is inverted on top of a gas jar of air and the glass plate is removed, what correctly describes the colors inside the gas jars after a long period of time, and why?

    After a long period, both gas jars will contain a uniform brown color. This is due to diffusion: the nitrogen dioxide molecules, despite being denser, will randomly move downwards into the air, and air molecules will randomly move upwards into the nitrogen dioxide, eventually leading to a homogeneous mixture throughout both jars.

More flashcard decks

• Thermochemistry and Thermodynamics flashcards (149 cards)
• Género Bacillus y Clostridium flashcards (100 cards)
• Ψηφιακά Παιχνίδια και Μάθηση flashcards (100 cards)
• Philosophy AS flashcards (100 cards)
• Nervous system flashcards (100 cards)
• ECG, IGEL and Iv flashcards (100 cards)

Browse every shared deck