hi everyone welcome to IGCSE study buddy where you can revise chemistry topics from the Cambridge IGCSE syllabus if you are enjoying our videos so far please don't forget to hit the like button and subscribe to our Channel in this video you are going to learn topic 1 states of matter Mata is everything around us that has mass and occupies space matter is made up of tiny particles there are three states of matter solids liquids and gases here are the basic properties that make solids liquids and gases different solids have a fixed volume they keep their own shape and particles inside are tightly packed liquids have a fixed volume but they take the shape of their container particles inside can move around a bit gases have no fixed volume they take the shape of their container particles inside move around freely let's describe the structures of solids liquids and gases in terms of particle separation Arrangement and motion so as we know matter is made up of tiny particles in solids particles are very close together with minimal separation in liquids particles are slightly separated compared to solids in gases particles are relatively far apart solids are arranged in a tightly packed orderly or regular pattern particles are Loosely arranged in a disorganized manner in the case of liquids gas particles have a highly disordered arrangement with particles spread out particles in solids vibrate in place but don't move around freely their motion is limited to Tiny back and forth movements particles in liquids can slide past each other allowing them to flow and take the shape of their container they have more freedom of motion compared to solids particles in gases move rapidly and freely in all directions they collide with each other and container walls creating pressure so solids have closely packed vibrating particles liquids have Loosely arranged particles that can flow and gases have widely spaced fast moving particles next changes of state melting is the change from a solid to a liquid when a solid is heated its particles gain kinetic energy and start moving faster that's because when a substance is heated its particles absorb heat energy and transform it into kinetic energy causing them to move faster the tightly packed particles in a solid vibrate faster until the solid melts at a specific temperature called the melting point the solid turns into a liquid for example ice which is a solid melts into water which is a liquid at its melting point which is 0 degrees Celsius boiling is the change from a liquid to a gas as you continue to heat a liquid its particles gain more kinetic energy so continuing to heat the substance in its liquid form causes particles to gain enough energy to turn into gas at the boiling point the liquid changes rapidly into a gas for instance water boils at 100 degrees Celsius during boiling the liquid turns into water vapor which is a gas boiling and evaporation both turn a liquid into a gas but they differ in how they occur boiling occurs when the liquid reaches its specific boiling point while evaporating can happen at lower temperatures over time and is a slower process so evaporation can happen at various temperature levels even at temperatures below the boiling point some particles in a liquid gain enough kinetic energy to escape and become gas for example puddles dry up as the liquid gradually evaporates into the air condensing is the change from a gas to a liquid when a gas loses heat its particles lose kinetic energy and slowed down and come closer together condensing can occur at a range of temperatures the gas condenses into a liquid for instance steam in the air can lose heat and condense into tiny water droplets freezing is the change from a liquid to a solid when a liquid loses heat its particles lose kinetic energy and slow down at the freezing point the liquid turns into a solid water freezes at zero degrees Celsius and its particles arrange themselves into a solid structure so heating a solid turns it into a liquid which is melting while cooling a liquid turns it back into a solid which is freezing heating a liquid turns it into a gas that's evaporation and cooling a gas turns it back into a liquid that is condensation Heating and Cooling curves help illustrate how temperature changes impact changes in the state of matter a heating curve shows how the temperature of a substance changes as it's heated over time at the start the substance is solid it warms up but it's still solid particles inside Shake faster when it reaches the melting point it starts turning from solid to liquid temperature stays steady heat goes into breaking bonds now it's fully liquid and the temperature goes up as it gets heated particles move more freely at the boiling point it changes from liquid to gas temperature stays constant while heat breaks forces between particles after boiling it's all gas if you keep heating the gas temperature rises this curve helps us see how temperature links to a substances state that is solid liquid or gas when we add Heat during a change in state temperature remains constant in a cooling curve the temperature of a substance is decreasing and it shows how the substance changes from a gas to a liquid to a solid when the substance cools down it goes through the reverse of what happens in a heating curve from gas to liquid to solid the horizontal sections on the curve represent moments when the substance is changing its state but the temperature remains constant during those changes the volume of a gas is greatly affected by changes in temperature and pressure when you increase the temperature of a gas its particles start moving faster and have more kinetic energy this increased kinetic energy causes the gas particles to collide more frequently and with greater force pushing them farther apart and pushing them against their container walls as a result the gas expands and takes up more space so higher temperature leads to increased volume when you increase the pressure on a gas you are basically squeezing it this makes the gas particles come closer together reducing the space they occupy so higher pressure leads to decreased volume conversely decreasing the pressure allows the gas particles to move further apart increasing the volume in summary raising the temperature makes a gas expand that is increase in volume while increasing the pressure makes it shrink that is decrease in volume next diffusion diffusion is the process where particles typically gas or liquid molecules spread out from an area of high concentration to an area of low concentration as we know the kinetic particle theory says that all matter is made up of tiny particles in constant random motion when particles are in a high concentration area they Collide frequently and move randomly as they Collide and exchange energy some particles gain enough energy to break away and move to areas with lower particle concentration this continuous motion and collision process causes particles to spread out until they are evenly distributed completing the process of diffusion finally the effect of relative molecular mass on diffusion of gases lighter gas particles are able to move faster and cover greater distances than heavier ones this means that a gas will diffuse more quickly when it has a lower relative mass for example helium is a very light gas with a low relative molecular mass because its atoms are very light oxygen has a higher relative molecular mass compared to helium therefore helium gas moves faster and covers greater distances than oxygen gas because helium is lighter that concludes topic 1 states of matter are you enjoying our videos are they helping you here's a way you can show your appreciation and support our continued efforts you may use YouTube super tanks to send us thanks thank you hope this video helped you please share your thoughts and suggestions in the comment section thank you for watching and please don't forget to subscribe to 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