Presentation is loading. Please wait.

Presentation is loading. Please wait.

Conservation Of Mass D. Crowley, 2007. Conservation Of Mass  To be able to explain why mass is conserved when substances dissolve Saturday, September.

Similar presentations


Presentation on theme: "Conservation Of Mass D. Crowley, 2007. Conservation Of Mass  To be able to explain why mass is conserved when substances dissolve Saturday, September."— Presentation transcript:

1 Conservation Of Mass D. Crowley, 2007

2 Conservation Of Mass  To be able to explain why mass is conserved when substances dissolve Saturday, September 05, 2015

3 Dissolving  See if you can identify as many facts about dissolving as you can…  What do you think will happen to the mass of water if salt is added to it?  Using these facts, write a small paragraph in your book why salt dissolves  See if you can identify as many facts about dissolving as you can…  What do you think will happen to the mass of water if salt is added to it?  Using these facts, write a small paragraph in your book why salt dissolves

4 Salt Dissolving  Some substances are soluble meaning they dissolve  They are able to mix completely with a liquid, forming a transparent mixture  Salt (the solute) dissolves in water (the solvent), and its particles become completely mixed in our newly formed solution.  But the mass stays the same - we do not loose any salt or water particles, they are just mixed up, which is why they become difficult to see  Some substances are soluble meaning they dissolve  They are able to mix completely with a liquid, forming a transparent mixture  Salt (the solute) dissolves in water (the solvent), and its particles become completely mixed in our newly formed solution.  But the mass stays the same - we do not loose any salt or water particles, they are just mixed up, which is why they become difficult to see SoluteSolventSolution

5 Particles Look at the particle model for the soluble sugar: - Sugar, added to the water Water

6 Particles Look at the particle model for the soluble sugar: - Water Sugar, added to the water Sugar and water solution

7 Particles

8 Demonstration  What will happen to the rice and peas when they are placed in water?  Can you identify what will happen in our particle model?  What can you say about the mass of the water and the peas?  What will happen to the rice and peas when they are placed in water?  Can you identify what will happen in our particle model?  What can you say about the mass of the water and the peas?

9 Mass  Remember - the mass always stays the same - even if the solute dissolves  Both substances are still there, however the solute may have mixed with the solvent forming a solution  Remember - the mass always stays the same - even if the solute dissolves  Both substances are still there, however the solute may have mixed with the solvent forming a solution

10 Getting Salt Back  Imagine you added some salt to water  The salt would dissolve in the water  How could you get your salt back?  Imagine you added some salt to water  The salt would dissolve in the water  How could you get your salt back?

11 Filtration  Filtration is great at seperating insoluble solids (like our pea) from the liquid  It does this by creating a barrier which the larger insoluble particles cannot pass  E.g. the large peas cannot pass through the filter (like using a sieve at home)  Why is this process no use in seperating salt from water (something which has dissolved)?  Filtration is great at seperating insoluble solids (like our pea) from the liquid  It does this by creating a barrier which the larger insoluble particles cannot pass  E.g. the large peas cannot pass through the filter (like using a sieve at home)  Why is this process no use in seperating salt from water (something which has dissolved)? Large peas do not dissolve (their particles remain together), so can be easily filtered using a sieve

12 Filtration  When something dissolves, the solute particles become spread throughout the solvent  Because the particles are so spread out, a barrier will not stop them (they pass straight through)  This is why filtration is no use  Instead we must use evaporation – boiling off the water and leaving the salt behind  You task it to dissolve 1 gram of salt in water and via evaporation get the salt back – most accurate wins!  When something dissolves, the solute particles become spread throughout the solvent  Because the particles are so spread out, a barrier will not stop them (they pass straight through)  This is why filtration is no use  Instead we must use evaporation – boiling off the water and leaving the salt behind  You task it to dissolve 1 gram of salt in water and via evaporation get the salt back – most accurate wins!

13 Dissolving  Remember, when something dissolves its particles spread throughout the solvent, forming a solution  This is a lot like diffusion, where the particles (net) went from an area of high to low concentration  How could you speed up dissolving?  Remember, when something dissolves its particles spread throughout the solvent, forming a solution  This is a lot like diffusion, where the particles (net) went from an area of high to low concentration  How could you speed up dissolving?

14 Heat!  The particles diffused quicker when they were heated - more heat gives them more energy, so they move quicker  This can be applied to diffusion - heat the particles and they will diffuse quicker  Try it yourself - get an equal quantity of water and sugar for two cups  With one cup, use tap water  With the other use boiling water  Add the sugar, and see which dissolves quicker! H/W - explain this to someone at home!  The particles diffused quicker when they were heated - more heat gives them more energy, so they move quicker  This can be applied to diffusion - heat the particles and they will diffuse quicker  Try it yourself - get an equal quantity of water and sugar for two cups  With one cup, use tap water  With the other use boiling water  Add the sugar, and see which dissolves quicker! H/W - explain this to someone at home!


Download ppt "Conservation Of Mass D. Crowley, 2007. Conservation Of Mass  To be able to explain why mass is conserved when substances dissolve Saturday, September."

Similar presentations


Ads by Google