So as not to mix types in a recovery system and to alert you to the presence of dangerous hydrocarbons like propane.
Answer: The number of moles in 250.0 L of He at STP is 11.0 mole.
Explanation:
- It is known that 1.0 mole of a gas at STP conditions will occupy 22.7 L.
- To show this information: STP means that T = 0.0 °C = 273.15 K and P = 1.0 kPa = (100/101.325) = 0.9869 atm.
- From the ideal gas law: PV = nRT.
- Where, P is the pressure in atm <em>(P = 1.0 atm at STP).</em>
- n is the number of moles (n = 1.0 mole).
- R is the general gas constant (R = 0.0821 L.atm/mol.K).
- T is the temperature in K (T = 273.15 K at STP).
- and now we can get the volume of 1.0 mole at STP: V = nRT/P
- V = (1.0 mole x 0.0821 L.atm/mol.K x 273.15 K) / (0.9869 atm) = 22.7 L.
- Now, we can get the number of moles of 250.0 L of He at STP:
<em>Using cross multiplication:</em>
1.0 mole → 22.7 L
??? mole → 250.0 L
- The number of moles in 250.0 L of He at STP = (250.0 L x 1.0 mole) / (22.7 L) = 11.01 mole ≅ 11.0 mole.
Answer:
Explanation:
i. From solid to liquid (melting)
For melting to occur, heat must be absorbed by the substance being melted. When the substance gains significant amount of heat, its particles begins to vibrate and move on top of one another.
ii. From liquid to solid (freezing or hardening)
In this phase change, heat is removed from the system. This allows for the molecules to lose their kinetic energies and form an ordered arrangement from their liquid or molten state.
iii. From liquid to gas (evaporation)
As randomness continues to increase, more heat is absorbed to break the attractive forces between molecules of liquids. Phase change from liquid to gas is a heat absorbing process.
iv. From gas to liquid (condensation)
In condensation, heat is lost by a substance. To condense or collect gas particles together, heat must be removed from the system. This allows for a diminished kinetic energy among the particles of the system.