Which of the following processes are spontaneous, and which are nonspontaneous? (a) Freezing of water at 2 °C (b) Corrosion of iron metal (c) Expansion of a gas to fill the available volume (d) Separation of an unsaturated aqueous solution of potassium chloride into solid KCl and liquid water

Video transcript

Hello. In this problem, we are asked to classify the following processes as spontaneous or non spontaneous recall. That a spontaneous process is one that occurs without any outside intervention process A Then we're given an icicle melting out of hand on a cold day, the melting point of water is zero degrees Celsius. So the temperature is greater than zero degrees Celsius, ice will spontaneously melt warm liquid water as long as the pressure remains constant. Even on a cold day, the temperature at our hand is going to be greater than 0°C and the pressure acting on our hand is going to be the atmospheric pressure. So it will be a spontaneous process. The next process we're asked to consider then is the conversion of water into steam at 120°C. The normal boiling point of water. He's a hard degree Celsius. This means that the external pressure is one atmosphere we call that a liquid will boil and its vapor pressure is equal to the external pressure. To water will be converted into steam At 120°C spontaneously, As long as the pressure remains. Such that the boiling point is less than 120°C. So this will also be a spontaneous process. Again, we're consuming that the pressure is such that the boiling point will be less than 120°C. And then process c we're given a stone rolling uphill. So at the top of the hill will have high potential energy and it's on the hill, we'll have low potential energy. So things always move spontaneously towards the lower energy state. So, in order to get this rock to move uphill, we would have to put in potential energy that would require an outside intervention. So that means that this is non spontaneous. And the last process we have the dissolution of assault in water. So a Salt lake city implied will spontaneously disassociate to form its ions and a quick solution. And so we know this to be true, we've ever put salt into water, you know that it will spontaneously dissolve. So do you then is also spontaneous. Thanks for watching. Hope. This helps.