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Mixtures and Solutions

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Melissa Nagode

on 20 December 2013

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Transcript of Mixtures and Solutions

FOSS Module: Mixtures and Solutions
Investigation 1
A mixture combines two or more materials that retain their own properties.
A solution forms when a material dissolves in a liquid (solvent) and cannot be retrieved with a filter.
Investigation 2
Is there a limit to the amount of salt that can dissolve in 50 mL of water?
How can you describe the amount of acid needed to saturate 50 mL of water?
Can an unknown chemical be identified by its solubility?
Investigation 3
What happens to the soft-drink solution
when you increase the amount of powder in a
given amount of water?
How can you determine which of two salt solutions is more
concentration?
How can you tell whether three solutions have different concentration?
Mastery
Final Exam
Investigation 1.1: Making and Separating Mixtures
Investigation 1.2: Separating a Salt Solution
I. Question
How do you separate a salt solution?
Investigation 1.3: Observing Crystals
I. Question
What is left when salt water solution is evaporated?
Investigation 3.1: Soft-Drink Recipes
I. Question
How much powder should we mix with 1000
mL of water to make a good tasting drink? 25 mL or 75 mL?
Investigation 4: Fizz Quiz
Investigation 2.1: Salt Saturation
I. Question
How much Salt is needed to saturate 50mL of water?
Investigation 2.2: Citric-Acid Saturation
I. Question
How much citric-acid is needed to saturate 50mL of water?
Investigation 2.3: The Saturation Puzzle
I. Question
Can the saturation of a
chemical be used to find out what the chemical is?
Investigation 3.2: Salt Concentration
Hypothesis
:
If we use a balance then it will/will not be able to determine differences in concentration of solutions.
Investigation 3.3: Mystery Solutions
I. Question
Will any combination of chemicals make a solution when mixed with water?

Inv. 4.1; Chemical Reactions
Inv. 4, Part 2: Reaction Products
I. Question
What are the results of a chemical reaction?
Inv. 4.3, Reaction in a Zip Bag
I. Question
What will happen when you combine calcium chloride, baking soda, and water in a zip bag?

http://www.teachertube.com/viewVideo.php?video_id=183575
Preview and Pretest
Always follow the safety procedures outlined by your teacher.
Never put any materials in your mouth. Do not taste any chemical unless your teacher specifically tells you to.
Do not smell any unknown material. If your teacher asks you to smell a material, wave a hand over the material to draw the scent toward your nose.
Avoid touching your face, mouth, ears, or eyes while working with chemicals, plants, or animals.
Do not mix unknown chemicals just to see what might happen.
Always wash your hands immediately after using chemicals.
Clean up spills immediately.
Clean up your work space after each investigation.
Be careful when using sharp or pointed tools. Always make sure that you protect your eyes and those of your neighbors.
Report all accidents, even small ones, to your teacher.
Follow directions and ask questions if you’re unsure of what to do.
Behave responsibly during science investigations.
Lab Safety
How can a mixture be separated?
How can a solution be separated?
What is the shape and pattern of a salt crystal?
How can you separate a dry mixture of gravel, powder, and salt?
I. Question
What will happen if you add water to each of these materials: gravel, powder, and salt?
II. Hypothesis
If we add water to gravel then ________________________________.
If we add water to powder then _______________________________.
If we add water to salt then ___________________________________.
III. Materials
 5 mL gravel
 5mL salt
 5 mL powder
 150 mL water
 3 stir sticks
 sticky notes
 3 cups
 hand lenses
IV. Procedure
1. Label the “G”, “P”, and “S”., 2. Add 5mL of gravel to the “G” cup.
3. Add 5mL of powder to the “P” cup., 4. Add 5mL of salt to the “S” cup.
5. Use the
hand lenses
to make observations about the materials and
record
your observations on Part 1 of the “Separating Mixtures” sheet.
6. Use the syringe to add 50 mL of water to each cup then stir each cup with a stir stick.
7. Make observations about the mixtures and record your observations on Part 2 of the “Separating Mixtures” sheet.
8. Now attempt to separate each mixture by using a screen first then filter paper. Place the screen over an empty cup and pour the contents of the mixture through the screen.
a. Use the FOSS Funnel to hold the filter paper while you pour the contents of the mixtures through the filter paper.
9. Record which methods of separation were successful on Part 3 of the “Separating Mixtures” sheet.
II. Hypothesis
If I test a salt solution then it will separate by …
__________________________________________________
III. Materials
 50 mL water
 2 Plastic Cups
 1 Craft stick
 Syringe
 Balance
 Gram weight set
 5 mL salt
 Evaporating Dish
 Sticky notes
IV. Procedure
1. Weigh 50 mL on the balance. Put 2 cups on the balance add 50 mL of water to one cup and add gram weights to the other cup until the balance is balanced.
2. Count the 50 gram pieces to get the mass of the water and record it on the “Making a Solution” sheet.
3. Make a salt solution with one 5 mL spoon of salt and 50 mL of water. Stir with a stir stick until solution is clear.
4. Weigh the salt solution to get its mass on the balance and record the mass on the “Making a Solution” sheet.
5. Subtract the mass of the water from the mass of the salt solution and to get the mass of the salt in the solution.
6. Label the underside of an evaporating dish with the class period and one of your group members names.
7. Pour just enough salt solution in the evaporating dish to cover the bottom. Bring the evaporating dish to the evaporating trays at the materials counter.
8. Check each day and make observations.
VI. Conclusion
My hypothesis’ that…____________________________________________
was true/false. The data showed…________________
Next time I would...______
VI. Conclusion:
(Yep, that's right! Write it all by yourself
You can do it!)
II. Hypothesis
If salt water solution is evaporated, then…
__________________________________________________
III. Materials
 Evaporated salt water solution
 hand lenses

IV. Procedure
1. Get the evaporated salt water solution in the evaporating dish from the evaporating tray.
2. Use the hand lenses to make observations about the remaining material.
3. Draw what you see through the hand lens and write a description in the conclusion.
VI. Conclusion
My hypothesis’ that…____________________________________________
was true/false. The data showed…________________
Next time I would...______
Investigation 1.4: Separating a Dry Mixture
I. Question
How can you separate a dry mixture of gravel, powder and salt?
II. Hypothesis
If we test a mixture of gravel, powder and salt, then it will separate by ...________________________
III. Materials
 5 mL gravel  5mL powder
 5mL salt  Plastic cup
 ____________  _________________
 ____________  ____________
IV. Procedure
1. Add one 5mL scoop of gravel, one 5mL scoop of powder, and one 5mL scoop of salt in a cup and stir.
2. _______________________________________________________________________________________
3. ______________________________________________________________________________________
4. etc.
V. Data:
Draw your set up and write your results in the space provided.

VI. Conclusion:
Don't forget to complete your conclusion.
Challenge Lab
Inv. 1.1 Vocabulary
Inv. 1, Part 1 Vocabulary
1. Mixture – two or more materials stirred together.
2. Property – a characteristic of an object, something you can observe such as size, color, shape, or texture.
3. Solution – a special mixture formed when a material dissolves is water.
4. Dissolving – a process in which one material disappears into another
material.
A solution is saturated when as
much solid material as possible has dissolved in the liquid.
Solubility is the property that
substances have of dissolving in solvents.
Solubility is different for
different materials and can change with temperature and different solvents.
Simple Solutions are composed
of two components: a liquid
solvent and a solid solute dissolved
in the solvent.
II. Hypothesis
If…__________________ ,
then…________________.
III. Materials
 1 Plastic Bottle  5 plastic cups  Foss funnel
 5mL spoon  4 sticky notes  .5 L container of water
 Syringe  Balance  Gram weights
 50mL of kosher salt  Safety goggles
IV. Procedure; Part 1:
1. Add 50mL of water to the plastic bottle.
2. Tape a sticky note to the side of each bottle and mark the water level on the note with a pencil by drawing a line. Label one bottle “water”, and the other, “salt solution”
3. Place the “salt solution” bottle under the funnel and add one level 5mL spoonful of salt to the bottle through the funnel.
4. Carefully, remove the bottle from under the funnel. Then cap the bottle and shake until the salt is fully dissolved and the liquid solution is clear.
5. Keep track of how many level
spoonfuls of salt you add in Data Table 1 below.
6. Repeat steps 3 – 5 until no more salt will dissolve into the solution.
7. Place a cup labeled "S" under the funnel.
8. Place a piece of filter paper in the funnel and wet the paper with a syringe of water.
9. Discard the water in the cup below the funnel into the .5 L cup of water.
10. Starting with an empty “S” cup below the funnel, pour the “salt solution” through the filter paper.
11. Place the “S” cup on one side of the balance and an empty cup on the other side, then measure and record its mass in Data Table 2.
12. Place a cup of 50mL of plain water on one side of the balance and an empty cup on the other side, then measure and record its mass in Data Table 2.
13. Find the difference of the two masses to find
the mass of the salt dissolved in the
“salt solution”.

II. Hypothesis
If…__________________________________ ,
then…___________________________________
III. Materials
 I Plastic Bottle  5 plastic cups
 Foss funnel  5mL spoon
 4 sticky notes  .5 L container of water
 Syringe  Balance
 Gram weights  50mL of citric-acid
 Safety goggles
IV. Procedure
Part 1:
1. Add 50mL of water to the plastic bottle.
2. Tape a sticky note to the side of each bottle and mark the water level on the note with a pencil by drawing a line. Label one bottle “water”, and the other, “citric-acid solution”
3. Place the “citric-acid solution” bottle under the funnel and add one level 5mL spoonful of citric-acid to the bottle through the funnel.
4. Carefully, remove the bottle from under the funnel. Then
cap the bottle and shake until the citric-acid is fully dissolved and the liquid solution is clear.
5. Keep track of how many level spoonfuls of citric-acid
you add in Data Table 1 below.
6. Repeat steps 3 – 5 until no more citric-acid will
dissolve into the solution. Answer the question below Data Table 1.
Part 2: 7. Place a cup labeled “C-A” under the funnel.
8. Place a piece of filter paper in the
funnel and wet the paper with a
syringe of water.
9. Discard the water in the cup below the
funnel into the .5 L cup of water.
10. Starting with an empty “C-A” cup below
the funnel, pour the “citric-acid solution”
through the filter paper.
11. Place the “C-A” cup on one side of the
balance and an empty cup on the other side,
then measure and record its mass in Data
Table 2.
12. Place a cup of 50mL of plain water
on one side of the balance and an
empty cup on the other side, then
measure and record its mass in Data
Table 2.
13. Find the difference of the
two masses to find the mass
of the citric-acid
dissolved in the
“citric-acid solution”.

II. Hypothesis
If we saturate 50 mL of water with the mystery chemical, then we can identify it with it's solubility.
IV. Procedure
1. Add 50 mL of water to the bottle and mark the water line with a sticky note.
2. Add 1-5mL scoop of the mystery chemical and shake until dissolved.
3. Repeat until saturation is reached.
4. Filter out any solid, or undissolved chemical.
Weigh the solution and subtract the amount of the water to get the chemicals solubility.
Concentration expresses a
relationship between the amount of dissolved material and the volume of solvent.
The more
material dissolved in a liquid, the more concentrated the solution.
A concentrated
solution can be made more dilute by adding solvent to the solution.
When equal volumes of
two solutions made from the same ingredients are compared, the heavier one is the more concentrated solution.
Apply content
introduced in previous parts.
II. Hypothesis
If we test different amounts of soft drink mix, then _________ mL will taste best.
III. Materials
 2 Pitchers  small paper cups
 Soft-drink mix  25 mL spoon
 1000 mL beaker
IV. Procedure
1. Observe the teacher as she prepares the
soft-drink mixtures from the “Soft-Drink Recipes” page.
2. Taste each soft-drink solutions and
record your observations and
comments on the “Soft-Drink Recipes” sheet.
V. Data
Thinking About Mixtures
1. two or more things mixed together. Can
be separated by a filter. Cereal and milk, trail mix.
2. a mixture where the solid material dissolves and can not be separated with a filter. Salt and water and lemonade.
3. It is two things mixed together but one dissolves, so it is both.
4. You know that it is a solution when the material dissolves.
5. Mixtures can be separated with filters.
6. Screen and paper filters both separate materials from liquids in a mixtures. Screens have larger holes than
paper filters.
Response Sheet--Separating Mixtures, p. 9
4. Kim is NOT correct; and you explain that a solution is a special kind of mixture where one material (solute) dissolves in another (solvent); a solution is always a mixture, but mixtures aren't always solutions.

3. Kim is NOT correct; you explain that mixtures are two or more materials stirred together and solutions are when one material dissolves into a liquid.

2. Kim is NOT correct; you include a description about either a mixture or solution but not both.

1. Kim IS correct; or incorrect descriptions of a mixture, solution or both.

0. Did not complete the response; not done.
"Mixtures and Solutions" Science Story Questions, p. 10
1. Sand, vegetables soup, lemonade, air, and the ocean.
2. By hand, filter or evaporation.
3. A substance that cannot be broken down any further.
4. Salt or sugar and water, corn syrup and water, carbon dioxide dissolved into water, and the air we breathe.
5. A solution is a special mixture where on material dissolves in another.
6. Solute - salt; solvent - water; solute is detergent and solvent is water.
7. By evaporation.
8. An atom
9. 92
"A Salty Story" Science Story Questions, p. 13-14
1. They used it to preserve food; it adds flavor.
2. By evaporation and mining
3. To salt icy roads; to add to animal feed; to soften water; to make chlorine and sodium.
4. Sodium and chloride
5. Compound
6. Chlorine is used to purify water, and make medicines and pesticides; sodium is used to make soap and medicines.

SALTY FACTS
1. A swelling of the thyroid gland in the neck caused by lack of iodine.
2. Iodine
3. David Marine, a physician.
4. It could end iodine deficiency in many countries.
"Earth Elements" Science Story Questions, p. 13-14
1. Liquid
2. Our body is like a vessel that contains water. Our solid structure makes us solid.
3. Five Elements
4. Carbon, oxygen, hydrogen, nitrogen, and calcium.
5. Only a few elements make up both things; water is common on Earth and in humans.
6. Earth and humans are composed of different elements in different amounts.
7. The elements combine in a huge variety of ways to create many different materials.
Inv. 1.3 Vocabulary, p.4
Evaporation
- To turn into a gas, like water into water vapor.

Crystal
- The solid form of a material that can be identified by its natural shape and pattern.
Inv. 2.1 Conclusion, p.21
VI. Conclusion
My hypothesis that

that
_______ g of salt would saturate 50 ml of water was true/false.
The data showed that
________ g of salt saturates 50 ml of water.
Next time I would
_______________________________________________
Use the equation to find out your hypothesis in grams.
Hypothesis number in ml = h
( h / 5 ) 4 = ______ g
Actual number of grams that saturate 50 ml of water
The last number on data table 2 on page 20.
Inv. 2.1 Vocab, p. 23
1. Saturated Solution - A solution in which as much solute as possible has been dissolved.

2. Solute - A substance that dissolves in a solvent to form a solution. Example: salt.

3. Solvent - A substance that dissolves a solute to form a solution. Example: water.
Stamp Sheet Key
Any colorful stamp = completed assignment - 10/10 points, 100%
No more than 1 missing part/question/vocabulary term
i = incomplete - 5/10 points, 50%
2 or more missing parts/questions/vocabulary terms
m = missing - 0/10 points, 0%
None of the assignment is complete

100% Stamp = that part of the journal is 100% complete and a prize is earned (except if the stamp sheet was lost since the last journal check).
Hand written score is the current overall class grade.
Each "Journal Check" box with a parent signature/initial will earn 1 extra credit point on the final exam.
Any assignments can be finished before the final Journal Check (last one on the Stamp Sheet) for full credit on their report card grade.
Inv. 2.1 Science Story Questions, p.24 - Corrections
"Decompression Sickness", p.13-15
1. Nitrogen
2. Decompression Sickness
3. They are pretty much the same; both are about nitrogen in the blood.
4. It causes a lack of muscle coordination, nausea, speech defects, and severe pain in the joints.
5. Air pressure decreases the as the altitude increases, allowing nitrogen to come out of the bloodstream.
6. The bends
Inv. 2.2 Vocabulary, p.23
Solubility
- the property that some substances have of being able to dissolve into water; like salt's solubility into water.
Example: Citric Acid is more soluble than salt.
VI. Conclusion
My hypothesis that we could use the mystery chemicals solubility to identify it was true. The data showed that its solubility was 50g and the chemical data sheet showed the solubility of Epsom salt as 48g. All of our solubilities were high.
Inv. 3.1 Vocabulary
1.
Concentration
- the amount of material dissolved in a liquid.
2.
Dilute
- to make a solution less concentrated, usually by adding more liquid.
3.
Volume
- the three-dimensional space occupied by something.
"Grow Your Own Crystals" and "The Air You Breathe"
Science Story Questions
1. A white mineral.
2. To clean and polish materials, as a water softener, as an antiseptic, and as an additive in fertilizers and medicines.

1. A solution of oxygen, carbon dioxide, and other gases dissolved in nitrogen.
2. Nitrogen is the solvent, and the other gases are the solute.
3. 78%
4. 20%
5. Argon, helium, krypton, neon, radon, and xenon.
6. More solute can dissolve when the solvent is warmer.
7. High concentrations of certain substances in the air.
8. The gradual rise in average temperatures on Earth.
9. Increased concentration of carbon dioxide and other substances in the air traps heat near the earth's surface.
10. Not yet, but some scientists think it may be possible in the future.
11. The pressure outside your body equals the pressure in side your body.
Inv. 2.2 Science Story Questions, p. 30 - Corrections "Sour Power", p.16-17
1. Sourness
2.
3. Lemons and Limes
4. Lemonade, sodas, jams and jellies
5. He discovered citric acid, nitrogen, chlorine, manganese, and oxygen
6. Late 1700's
7. Yes, to let other scientists know about their discoveries. It might help people.
8. Bitter, sour, salty, and sweet
9. (See the picture)
10. Help us know if food is safe to eat
Inv. 2 Response Sheet "Reaching Saturation" - Corrections, p. 28
4 points
You agree that Mack's suggestion to add more water would also work
You also say that Jasmine should heat the solution to dissolve more iced-tea powder would also work.
You explain that water that is heated can dissolve more material, and that adding more water would also dissolve more material.
3 points
You agree that Mack's suggestion to add more water would work
You also say that Jasmine should heat the solution to dissolve more iced-tea powder would also work.
2 points
You agree that Mack's suggestion to add more water would work
1 point
You
do not
agree that Mack's suggestion to add more water would work
Conclusion
:
My hypothesis that using a balance
will/will not
determine the concentration of a solution was
true/false
. The data showed that more concentrated solutions weigh more than less concentrated solutions when comparing the same volume.
II. Hypothesis
If we mix different chemicals with water then...____________________________________
V. Materials
 3 plastic cups  3 craft sticks
 50mL syringe  5mL citric acid
 3 sticky notes  5mL baking soda
 5mL (one spoon) Assigned chemical
 5mL calcium chloride
 Fizz Quiz Place Mat
 .5 L container of water
VI. Procedure
Write your hypothesis.
Part 1 – Testing new chemicals:
1. Getter 1: go to materials counter and add one 5mL scoop of your group’s assigned chemical to the cup labeled for that chemical.
2. Return to group and add 50mL of water to the chemical with the 50mL syringe and stir with a stir stick.
3. Record any observation (feel, see, hear, and smell - don’t taste) in your notebooks.
4. Getter 2: Dump the mixtures in the sink, rinse the cups, and return to groups.

Part 2 – Testing combinations of chemicals:
5. Fizz Quiz Place mats will help organize the next part.
6. Label your 3 cups “1, 2, and 3”. Each will contain a different pair of chemicals.
7. Getter 1: go to materials counter with “cup 1” and add one 5mL scoop of calcium chloride, and one 5mL scoop of baking soda.
8. Getter 2: go to materials counter with “cup 2” and add one 5mL scoop of calcium chloride, and one 5mL scoop of citric acid.
9. Getter 1: go to materials counter with “cup 3” and add one 5mL scoop of baking soda, and one 5mL scoop of citric acid.
10. Add 50mL of water to each cup, stir, and record observations on the Fizz Quiz Observations sheet.
11. Write your conclusion with your group.

V. Data
Observations
(See, smell, feel, hear
– don’t taste)

___________________________ ____________________________
(Assigned Chemical)
VI. Conclusion
What happens when a solution is made with water and two different solutes?
How do you know when a chemical reaction has occurred?
Can the products of a chemical reaction be separated for further study?
How can you find out if the liquid that came through the filter is a solution?
What might happen if you conduct a gas producing reaction in a closed zip bag?
When a change results from mixing two or more materials, that change is a chemical reaction. A reaction results in new materials.
Formation of a gas occurs in some reactions.
Formation of a precipitate occurs in some chemical reactions.
Some products of a reaction are soluble and can be observed only after evaporating the solution.
Not all chemicals react when combined.
II. Hypothesis
III. Materials
 FOSS Funnel  Filter paper
 Evaporating Dish  Evaporating Tray
 Calcium Chloride  Baking Soda
 Water  5mL spoon
 Syringe  Stir stick
 Sticky notes  Mixture 1 from
Chemical Reactions Lab
IV. Procedure
1. Add one 5mL spoon of calcium chloride, one 5mL spoon of baking soda, and 50mL of water to a cup to make Mixture 1. Stir.
2. Write the recorder’s name and class period on the edge of the filter paper with a pencil.
3. Filter the un-dissolved participate with the FOSS Funnel and filter paper.
4. Lay the filter paper on the counter to dry
5. Label the underside of the evaporating dish with the recorder’s name and class period on a sticky note.
6. Pour a small amount of the filtered solution into an evaporating dish and place on an evaporating tray.
7. When both have dried completely, make observations using a magnifying glass, and record results.

VI. Conclusion
II. Hypothesis
If I combine calcium chloride, baking soda, and water in a zip bag, then __________________________________
Because _____________________________________
III. Materials
 10 mL of calcium chloride  10 mL baking soda
 50 mL water  zip bag
 Syringe

IV. Procedure
1. Add one 5mL scoop of calcium chloride in the zip bag.
2. Add one 5mL scoop of baking soda in the same zip bag.
3. Zip the bag almost closed pushing all the air out, and leaving a small space for the tip of a syringe to fit in.
4. Add 50mL of water with the syringe and immediately zip the bag closed.
5. Gently shake the bag.
6. Record your observations of the events in the
V. Data
Answer the following questions to record your observations.
What happened to the bag?
Why did that happen?
Where did the gas come from?
What did you find out by doing this in a bag instead of in a cup?
How much gas formed as a result of the reaction?
How does the volume of gas compare to the volume of chemicals you put in the bag?
VI. Conclusion
My hypothesis that…
__________________________________
was true/false. The data showed…
__________________________________
If we added all three chemicals to the bag then…
__________________________________
Inv. 4 Vocabulary
Chemical Reaction
-
when two or more materials (chemicals) are mixed together and a change occurs
Precipitate
-
a solid material that forms as a product of a reaction.
Reactants
-
chemicals that react only when
they are mixed.
1. ___e___ Mixture 2. ___c___ Property 3. ___a___ Solution 4. ___f___ Dissolving
5. ___d___ Evaporation 6. ___b___ Crystal 7. ___c___ Saturated Solution 8. ___d___ Solute
9. ___a___ Solvent 10. ___b___ Solubility
11. Why doesn’t the screen work to separate the powder from the water in a powder and water mixture?
The
holes are too large
to catch the
small powder particles
. The water and the
powder passes through
.

12. Why doesn’t the screen or filter paper work to separate the salt from the water in a salt and water solution?
The
salt is completely dissolved
by the water and the water and salt pass through the filters.

13. How do you separate the solute from the solvent in a salt and water solution?
Evaporate
the solution in an evaporating dish. (+1)
The solvent (water) will evaporate ad the solute (salt) will be left behind
.

14. How are mixtures and solutions the same?
Both are
two or more materials mixed together.

15. How are mixtures and solutions different?
Solutions
are special mixtures where one material
dissolves
into the liquid.

16. ___F___ Mixtures are specials types of solutions.
Solutions
are special types of
mixtures
17. ___T___ Crystals are different for every chemical.
18. ___F___ Mixtures in the lab should sometimes be separated with your hands.
Mixtures in the lab should
never
be separated with your hands.
19. ___T___ Mud is an example of a mixture.
20. ___F___ Conclusions should start with the word(s) “If…”.
Conclusions should start with the word(s)
“My hypothesis that…”.
21. ___F___ Hypothesis’ should start with the word(s) “My hypothesis that…”.
Hypothesis’ should start with the word(s)
“If…”.
22. ___F___ In the metric system 1mL of water always weighs 50g of water.
In the metric system 1mL of water always weighs
1g
of water.
23. ___F___ Aprons should be warn at all times when using chemicals in the lab to protect your clothes.
Goggles
should be warn at all times when using chemicals in the lab to protect your
eyes
.
24. ___T___ When a solvent is heated it can dissolve more solute.
ANSWER___KEY
Mixtures and Solutions
Inv. 3 and 4 Quiz-let

Vocabulary Matching
Match the definition to the correct vocabulary term by writing its letter on the line next to the word.

Inv. 3 and 4 Vocabulary

1. ___e___ Concentration a. Chemicals that react only when they are mixed.
2. ___d___ Dilute b. The three-dimensional space occupied by something.
3. ___b___ Volume c. A solid material that forms as a product of a reaction.
4. ___f___ Chemical Reaction d. To make a solution less concentrated, usually by adding more liquid.
5. ___c___ Precipitate e. The amount of material dissolved in a liquid.
6. ___a___ Reactants f. When two or more materials (chemicals) are mixed together and a change occurs

Short Answer

7. What are the 3 signs of a chemical reaction?
A gas is formed – bubbles, fizzing; A temperature change; A precipitate is formed.

8. If every lab group in class made a saturated salt solutions the same way with the same temperature water, will the concentrations of those saturated solutions be the same or different? Why?


The concentrations would be the same, because the saturation point is the amount of materials a solution can dissolve at a certain temperature.

9. Give one example of a reaction product.

Gas, precipitate, or temperature

10. What evidence do you have that a solution is saturated?

No more material will dissolve.

11. Put these solutions in order from least to most concentrated?
Solution 1 - 50mL water/5mL salt
Solution 2 – 50mL water/15mL salt
Solution 3 – 100mL water/20mL salt

Least concentrated – Solution 1, then Solution 3; Most concentrated is Solution 2.

12. If 5mL of salt weighs 4 grams, give the weights for solutions 1, 2, and 3 from question 11.
Solution 1 = 54g; Solution 2 = 62g; Solution 3 = 116g

13. When saturation has been reached a solution is as concentrated as it can be – unless you do what?

(2 points) Heat the solvent. (1 point) Add more solvent.

True or False
If the answer is false, rewrite the sentence and change the bold words to make it correct.

14. ___F__ All chemicals react when they are combined to form either a gas, temperature change or a precipitate.

Not all chemicals react when they are combined to form either a gas, temperature change or a precipitate.

15. ___T__ A chemical reaction is when a change occurs when mixing two or more chemicals.

16. ___T__ A solution can sometimes be made of two materials dissolved into a liquid.

17. ___F__ Increasing the amount of lemonade powder in a certain amount of water makes it more dilute.

Increasing the amount of lemonade powder in a certain amount of water makes it more concentrated.

18. ___F__ When you weigh solutions of the same volume, more concentrated solutions are lighter than less concentrated solutions.

When you weigh solutions of the same volume, more concentrated solutions are heavier than less concentrated solutions.

19. ___T__ When your lemonade tastes too strong you can add water to dilute it.
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