Cooling/heating Curves, Solutions and Solubility Curves Flashcards
Why does hydrogen escape from a balloon much faster than carbon dioxide?
Hydrogen molecules are much lighter than carbon dioxide molecules.
Why does the temperature remain constant when a liquid boils?
All of the heat energy is going into breaking the bonds between particles so the liquid can become a gas, rather than heating the liquid.
What is the difference between evaporation and boiling?
Evaporation can happen below the boiling point.
What is the effect of impurities on the melting point of a substance?
Impurities lower the melting point.
Why is rock salt used on roads in winter?
In winter rock salt is used on roads to lower the melting point of ice so that roads don’t freeze in lower temperatures.
What is the effect of impurities on the boiling point of a substance?
Impurities increase the boiling point.
Why don’t all liquids have the same boiling point?
Some liquids have stronger forces of attraction between their particles so require more energy to break these bonds and therefore have a higher boiling point.
What is evaporation?
When molecules at the surface of a liquid have enough energy to escape as a gas.
What is boiling?
When all the molecules in a liquid have enough energy to overcome the forces of attraction and become a gas.
What is a boiling point?
The temperature at which the vapour pressure is equal to the atmospheric pressure.
Explain in terms of vapour and atmospheric pressure what happens during boiling.
The vapour pressure rises until it is equal to the atmospheric pressure so that the vapour pressure within the bubbles is high enough to stop them collapsing under the pressure of the surrounding water and they can rise and break the surface.
Why does water boil at a lower temperature at the top of Mt Everest?
The atmospheric pressure on top of Mt Everest is lower so the vapour pressure does not have to rise as much and the particles can become a gas much more easily at a lower temperature.
