Separating Solutions

Q1: Describe the physical properties of the substance that remains in the evaporating dish.

A1: The substance in the dish has these physical properties: white in colour, mushy, closer together, softer, warmer, and wetter.

Q2: Where is the water that was in the salt water solution?

A2: The water is now in the air, adding to the humidity of the room. The air has dissolved the water, forming a cloud.

Q3: What do you think the substance is that remained in the evaporating dish?

A3: I think the substance is fresh salt because it was burnt to a point where the bacteria would die. Some of the bacteria could have mixed with the water.

Q4: What could you do to identify the substance?

A4: I could test its density, solubility and mass. I could just test all physical properties.

Q5: Explain why scientists would classify cereal as a heterogeneous mixture.

A5: Cereal looks different from the top to bottom and is not evenly distributed throughout.There are different colours and sizes, which makes it look different.

Q6: After a minor traffic accident, the police noticed that a solution had spilled and run off

the roadway onto the shoulder of the road. Describe how you could recover a

sample of this solution from the dirt, rocks, and sand on the road’s shoulder.

A6: I could use tweezers to remove the rock from the mixture, then use a spoon to get the sand and dirt. You should then be left with some unabsorbed solution in the cup.

Q7: When a scientist mixed together a number of substances, light, heat, and gas were

produced. The scientist could not separate the new substance using physical

properties like solubility, density, or color. Did the scientist create a mixture, or did

she produce something else? Explain how the product she produced was alike and/or

different from the homogeneous and heterogeneous mixtures you have used.

A7: The scientist produced a compound or something else, but definitely not a mixture because a mixture can be easily separated, a solution is a bit harder, but this is much harder than a solution. This is like a homogeneous mixture I have used because light is bright and same colour from top to bottom, heat is invisible and so is gas.

Solubility Questions

1. Mr.Anderson described solubility as how easy it is for the solute to dissolve in a given solvent. If the solubility is low then it is hard for the solute to dissolve but if the solubility is high it is easy.

2. Talc is insoluble because it cannot mix with water no matter how much you stir. Even if you stir a really small amount, it won’t dissolve.

3. Increasing the temperature of the solvent will increase the solubility of a solute because it will allow more of the solute to go in and dissolve.

4. There is less oxygen near the equator than at a higher latitude because colder water allows more air to dissolve than warmer water.

5. The fish keep dying because of the warm water. The warm water cannot dissolve as much oxygen as the previous cold water. This is why the fish die.

Boiling Point lab 2

  1. What is the boiling point of water in degrees Celsius and Fahrenheit? The universal known boiling point of water is 100 degrees celsius or 212 degrees fahrenheit.
  2. How does the boiling point of water change at altitudes below sea level? The boiling point rises the lower your altitude because the atmospheric pressure becomes higher.
  3. Does water containing impurities boil at a higher or lower temperature than pure water? It will boil at a higher temperature because the impurities will need to be heated up as well.

Lab 1: Boiling point

I predicted that the ice would completely melt at 10 degrees celsius  but we started at 19.2 degrees so I don’t know whether that was right or not. I predicted that the water would boil at 100 degrees celsius and I was 0.1 degrees off. Our water boiled at 99.9 degrees celsius.

1. The temperature of a substance rises as the heat and energy increases. The data from the graph shows that the temperature of the water rose higher and higher as the temperature of the hotplate increased.

2. In the first one, all the molecules are waiting for the solid to completely melt. Once the solid melts, they are finally be able to break free of the bonds and attractions so that they can start making heat again. They need to stop once the liquid reaches boiling point because they have to wait for the liquid to turn into gas so that they can break free of the bonds and attractions. Once the liquid turns completely into gas, they can continue producing heat.

3. During my observations I noticed that near the start of when it turned into liquid, the molecules were calmer and there weren’t many bubbles, but as it became hotter and hotter, the water molecules started going mad through the bubbles when the were turning into water vapour or steam. This happened because in particle theory the liquid’s molecules will become freer and freer as it becomes hotter and hotter.

4. a) Why did our water level go down when our ice melted?

b) How do the molecules actually separate? Is it because of the heat or is there a better explanation as to how they break?

c) How long does it take for all of the water to turn into gas?

d) If we used a different container to hold the water and ice in, would we have gotten different results?

e) Does the container affect the boiling point?

Sink or Float

I noticed that the objects that had less mass than volume would float since the density is calculated by dividing mass by volume so if the volume is more than the mass the object will float because if it goes below 1 then it will float.I noticed that the objects that had less mass than volume would float since the density is calculated by dividing mass by volume so if the volume is more than the mass the object will float because if it goes below 1 then it will float. I noticed that the hollow objects were all floating since they were filled with air and air floats. Most of the not hollow objects were sinking because it was only the object that was being calculated. One seems to be the magic number because water at 4 degrees celsius is 1 g/cm3 and that is what all densities are based out of. I saw that some of the calculations were incorrect because we said that the object floats but the density was more than 1. I am wondering how we get irregular shaped objects volume if they float.

Density and Slope Lab

1. Aluminium with the volume of 12 cm3 would weigh 31 grams on my chart.

2. Gray Plastic with the volume of 12 cm3 would weigh 17 grams on my chart.

3. Aluminium is heavier.

4. Aluminium

5. Yes. I think the connection is that the more dense an object is, the steeper the slope is when the data is graphed.

6. ?

7. Aluminium – 2.70 g/cm3  Gray Plastic – 1.10 g/cm3 Aluminium is heavier.