Writing Prompts2B: Polymers

Guidance on Student Use:Below are writing prompts related to content learned in this unit as well as recommended assessment probes. The assessment probes can be found in a series of books titled “Uncovering Student Ideas”. One copy of each of these books has been provided to each school’s science department. The names of each book and the shorthand used to denote the books follow.

Uncovering Students Ideas in Science: 25 Formative Assessment Probes, Volume 1 (Vol . 1)

Uncovering Students Ideas in Science: 25 More Formative Assessment Probes, Volume 2 (Vol. 2)

Uncovering Students Ideas in Science: Another 25 Formative Assessment Probes, Volume 3 (Vol. 3)

Uncovering Students Ideas in Science: 25 New Formative Assessment Probes, Volume 4 (Vol. 4)

Uncovering Students Ideas in Physical Science: 45 New Force and Motion Assessment Probes, Volume 1 (PS)

Indicators with Related Writing Prompts and Assessment Probes4.1.3 The student will explain how atoms interact with other atoms through the transfer and sharing of electrons in the formation of chemical bonds.

-formation of ions-bond-formation of ionic bond-formation of covalent bond-ionic and molecular substances

Writing Prompt: The Town’s WaterAssessment Probes: Is it Made of Molecules? (Vol. 1, p. 85), Chemical Bonds (Vol. 2, p. 71), Salt Crystals (Vol. 4, p. 39)

4.2.1 The student will explain how the properties of a molecule are determined by the atoms it contains and their arrangement.

-polar and nonpolar molecules -water

Writing Prompt: Packing PeanutsAssessment Probes:

4.2.2 The student will explain why organic compounds are so numerous and diverse.-inorganic and organic compounds -ability of carbon to form chains and make rings

Writing Prompt: High Octane

Assessment Probes: Is it food for plants (Vol.2, p. 113)

4.2.3 The student will describe the properties of solutions and explain how they form.-solute, solvent, and solubility -concentration -dissociation/ionization -electrolytes

Writing Prompt: Make it SweetAssessment Probes: Sugar Water (Vol. 4, p. 11)

4.2.4 The student will differentiate among acids, bases, and salts based on their properties.-Arrhenius definition-salts-indicators

Writing Prompt: Stomach Ache, Protect My Teeth, Pink or Blue?Assessment Probes:

4.4.1 The student will illustrate that substances can be represented by formulas.-subscripts-acids

Writing Prompt: Disorganized Supply RoomAssessment Probes:

Unit 2B: Polymers Packing PeanutsEssential Question How does the arrangement of atoms in a compound affect how

that compound behaves in a solution?Indicator(s) 4.2.1 The student will explain how the properties of a molecule

are determined by the atoms it contains and their arrangement.

A new package delivery company has a goal of being environmentally friendly. They did some research and found out that boxes are often recycled, but packing peanuts (small foam pieces used to protect delicate objects) are usually thrown out. The average peanut can take up to 50 years to decompose but some brands claim to degrade much quicker. These companies claim that water dissolves their peanuts. The company wanted to test these claims before supporting one particular packing peanut brand. To test the claim they put one peanut in a beaker of water for 1 hour. Below are the results.

Brand A in water Brand B in water Brand C in water

WATER MOLECULE

Explain why some packing peanuts dissolve in water and others do not. In your reponse, be sure to include:

what determines if one substance will dissolve into another substance. the type of substance that water is: ionic, polar covalent or nonpolar covalent. The type of substance that each brand of packing peanut might be: ionic, polar

covalent or nonpolar covalent.

Be sure to consider the completeness of your response, supporting details, and accurate use of terms.

H H

O

Unit 2B: Polymers Make it SweetEssential Question What factors affect the amount of substance that will dissolve

into a solution?Indicator(s) 4.2.3 The student will describe the properties of solutions and

explain how they form.

A student’s favorite drink is sweet tea. Every morning he makes it by adding exactly thirty grams of sugar and one tea bag to one liter of hot water. Some days his tea does not taste as sweet as other days. Those same days he notices that there is sugar sitting at the bottom of the cup that will not dissolve no matter how long he stirs. He decided to filter out the remaining sugar and keep track of the data in the graph below.

Day 1 Day 2 Day 3 Day 4 Day 5 Day 6 Day 70

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

Amount of Sugar Undissolved in One Liter of Tea

Amou

nt o

f Sug

ar U

ndiss

olve

d (g

ram

s)

Explain why different amounts of sugar might dissolve at different times. In your reponse, be sure to include:

which day the least sugar dissolved and which day the most sugar dissolved. what could have caused less sugar to dissolve on some days. what the student could do to his drink to make more sugar dissolve.

Be sure to consider the completeness of your response, supporting details, and accurate use of terms.

Unit 2B: Polymers Disorganized Supply RoomEssential Question What are the properties of acids and bases?Indicator(s) 4.4.1 The student will illustrate that substances can be

represented by formulas.

A new chemistry teacher goes into the back room of her classroom to see what chemicals and equipment are available. She is surprised to see that the chemicals were on the shelves in an unorganized manner. This is a problem because it makes it harder to find what is needed, but more importantly it could be unsafe if there are spills and unintended reactions. For example, acids and bases should not be stored next to each other because a lot of heat is produced when they react. She begins to feel overwhelmed but remembers that she has some students assigned to help her get organized. Also, she is relieved when she notices that each bottle has a label with the chemical’s formula. She decides to write down some important information for the students who will be helping her.

Indicate the important information that the student helpers will need about acids, bases and salts. In your reponse, be sure to include:

how acids, bases and salts can be distinguished using their formula. examples of formulas of acids, bases and salts. an explanation of the reaction that occurs between acids and bases.

Be sure to consider the completeness of your response, supporting details, and accurate use of terms.

Unit 2B: Polymers Stomach AcheEssential Question What are the properties of acids and bases?Indicator(s) 4.2.4 The student will differentiate among acids, bases, and salts

based on their properties.

Your friend had an upset stomach caused by indigestion. His mother explained to him that indigestion is when the contents in the stomach are too acidic. She also told him to drink soda to settle his stomach. The soda did not help. You tell him that you would not have expected the soda to help with the indigestion based on what you know about acids and bases.

Explain why soda would not help settle your friend’s stomach. In your reponse, be sure to include:

a better alternative to drinking soda. how each substance above would react with the stomach acid. defining characteristics of acids and bases, besides how they react.

Be sure to consider the completeness of your response, supporting details, and accurate use of terms.

Acidic Neutral Basic

Soda

Appl

es

Brea

d

Wat

er

Tea

Eggs

Baki

ng S

oda

Unit 2B: Polymers Protect My TeethEssential Question How is acidity measured?Indicator(s) 4.2.4 The student will differentiate among acids, bases, and salts

based on their properties.

A student went to the dentist and found out that he had a cavity. He always brushes his teeth twice a day, so he didn’t understand how he got a cavity. The doctor told him drinking things every day that are acidic, such as lemonade, can contribute to cavities. He didn’t drink lemonade but did drink a variety of other drinks. The next day he brought in a sample of each drink and asked his science teacher to borrow a pH probe to test each liquid. Below are the results of the tests.

Drink A Drink B Drink C Drink D Drink E

Explain which drink(s) the student should avoid if he wants to protect his teeth from further damage. In your reponse, be sure to include:

an explanation of what pH measures. which drinks are acidic, basic, and neutral.

Be sure to consider the completeness of your response, supporting details, and accurate use of terms.

11.9pH

7.0pH

5.3pH

9.8pH

2.4pH

Unit 2B: Polymers Pink or Blue?Essential Question How does pH affect living organisms?Indicator(s) 4.2.4 The student will differentiate among acids, bases, and salts

based on their properties.

Hydrangea is a unique flower. It changes color based on the acidity or basicity of the soil. Florists use this information to purposely change the color. Below is a table indicating the color of the flower based on the pH of the soil.

Color of Hydrangea Based on pHpH Color4.5 deep blue5.0 medium blue5.5 purple6.0 purplish-pink6.5 medium pink7.0 deep pink

Explain how acidity and basicity affect hydrangeas. In your reponse, be sure to include: the trend of how acidity or basicity affects the color of a hydrangea. what a substance that changes color in the presences of an acid or a base is

called. a prediction of what would happen to a hydrangea if the pH of the soil were very

high or very low.

Be sure to consider the completeness of your response, supporting details, and accurate use of terms.

Unit 2B: Polymers The Town’s WaterIndicator(s) 4.1.3 The student will explain how atoms interact with other

atoms through the transfer and sharing of electrons in the formation of chemical bonds.

A town just built a water tower. The mayor of the town wanted the water to contain fluoride so that all of the residents would have healthier teeth. He read that ionic compounds must be used to get the fluoride into water. He looked up fluorine containing compounds and came up with the following list.

NaF NF3 SiF4 CaF2 NH4F

Explain which compound(s) could be used to get fluoride into the water. In your reponse, be sure to include:

which compounds are ionic and which are covalent. how ionic and covalent compounds are different. why only ionic compounds would produce fluoride in water.

Be sure to consider the completeness of your response, supporting details, and accurate use of terms.

Unit 2B: Polymers AnalogiesEssential Question How are products of chemical reactions predicted?Indicator(s) 4.5.1 The student will describe the general types of chemical

reactions.

A tutor comes up with analogies to help students to remember the types of reactions: single displacement, double displacement, synthesis and decomposition. He represents the analogies with the pictures below.

Analogy 1: → +

Analogy 2: + → +

Analogy 3: + →

Analogy 4: + → +

Explain how the analogies relate to the types of chemical reactions. In your reponse, be sure to include:

the type of reaction that each analogy represents: single displacement, double displacement, synthesis and decomposition.

a description of what happens to molecules in each type of reaction.

Be sure to consider the completeness of your response, supporting details, and accurate use of terms.

Unit 2B: Polymers Silver ProductionEssential Question How are chemical reactions represented?Indicator(s) 4.5.2 The student will balance simple equations.

A science teacher comes across an old jar of silver (II) fluoride (AgF2). She knows that it is not used for any experiments used in class and thinks about disposing of it. Then she realized that she could do a reaction to form solid silver (Ag), which is valuable. She contemplates many reactions to determine the best one. One of the steps to determining the best reaction is balancing the reactions.

___AgF2 + ___K → ___KF + ___Ag

___AgF2 + ___Zn → ___ZnF2 + ___Ag

___AgF2 + ___Al → ___AlF3 + ___Ag

___AgF2 + ___Sn → ___SnF4 + ___Ag

Explain how to balance the reactions. In your reponse, be sure to include: the four balanced equations. an explanation of why equations must be balanced. how having balanced equation might help the teacher determine which reaction

to use.

Be sure to consider the completeness of your response, supporting details, and accurate use of terms.

Unit 2B: Polymers The Dangers of CleaningEssential Question How are chemical reactions represented?Indicator(s) 4.4.1 The student will illustrate that substances can be

represented by formulas.

An article in the local newspaper had an interview with a man whose lungs were damaged when he inhaled chlorine gas. The paper stated that this happens more frequently than one might expect. The mixing of cleaning products is one possible scenario where this may occur. Some products contain bleach (NaOCl) and other products contain ammonia (NH3). When these two chemicals come in contact, they react to form chlorine, a green, toxic gas. The reaction represented below.

2 NaOCl(aq) + 2 NH3(aq) → 2 NaONH3(aq) + Cl2(g)

Explain how equations are used to represent chemical reactions. In your reponse, be sure to include:

what each number in the equation indicates. what each letter in the equation indicates. what each symbol in the equation indicates.

Be sure to consider the completeness of your response, supporting details, and accurate use of terms.