Conservation of Matter
Mia mixed 200 grams of lemon juice with 10 grams of sugar. What is the total weight of Mia’s lemonade?
Mia total = 200+10=210 grams
Name the state of matter for: lemon juice , sugar , and water vapor from boiling . Write one word for each.
lemon juice — liquid
sugar — solid
water vapor — gas.
What two household chemicals were used to clean the pennies in Laila’s experiment?
Salt and Vinegar
Look at the lemonade table: Mia 200 g + 10 g, Kayla 200 g + 20 g, Eli 200 g + 30 g. What pattern do you notice in the totals as sugar increases? State the pattern in one sentence.
Each person adds 10 grams of sugar which would result in an increase of 10 grams for the total.
Kayla mixed 200 grams of lemon juice with 20 grams of sugar. Eli mixed 200 grams of lemon juice with 30 grams of sugar. Which of these has the greatest total mass, and by how many grams compared to Mia’s lemonade?
Eli total = 200+30=230; Difference vs Mia = 230−210=20 grams
When lemonade is frozen into a popsicle, the lemonade changes from one state of matter to another. Which change is this? Explain in one sentence what happens to the particles when a liquid freezes
Liquid → solid (FREEZING)
particles slow and pack tighter.
In the sealed bag and baking soda cups experiment, bubbles form when baking soda mixes with vinegar. What is being produced that makes bubbles? (Choose from: solid, liquid, gas.)
Gas is produced (bubbles)
In the penny experiment, Laila’s pennies look shiny after soaking. What observable change (not mass) happened to the pennies? Give one likely explanation using chemical reaction language.
for example: a reaction removed the brown layer
After freezing lemonade into popsicles, will the total mass of each batch change because of the freezing? How do you know?
False — mass is conserved when freezing (total mass stays the same)
In the penny-cleaning experiment, the vinegar is a liquid and any gas produced would be a gas. If a closed bag expanded in the baking-soda + vinegar picture, what state of matter caused the bag to expand?
Gas; bubbles are gas particles filling space.
Based on Priya’s experiments:
Powder A + vinegar = bubbles; Powder A + water = bubbles.
Powder B + vinegar = bubbles; Powder B + water = no bubbles.
Powder C + vinegar = no bubbles; Powder C + water = no bubbles.
Which powder is most likely baking powder, and why? Use evidence from both experiments.
Powder A is baking powder (bubbles with vinegar and water);
Powder B is baking soda (bubbles with vinegar only);
Powder C is salt.
If there are different amounts of baking soda in separate cups. What noticing could you record about how bubble size or bag expansion might change with more baking soda? Write one clear observation prediction.
The more baking soda will produce more bubbles which are reacting with the vinegar. The bag size will continue to expand because the of the gas particles being produced.
Laila weighed her pennies before the cleaning experiment and they weighed 10 grams. After the salt & vinegar cleaning, the pennies weighed 8 grams. The salt & vinegar solution weighed 15 grams before the experiment. Explain (in one or two sentences) what likely happened to the solution’s mass after the cleaning so that total mass is conserved.
After the pennies were cleaned with the salt and vinegar solution, their weight went down by 2 grams, that means the weight of the solution went up by 2 grams. The weight of the solution is now 17 grams because the particles went from on the pennies to being diluted in the solution. The mass of the salt and vinegar solution and dirty pennies is conversed not lost.
Draw (or describe) how particles are arranged differently in a solid, liquid, and gas. Give one sentence describing particle movement for each state
Particles in a SOLID are tightly packed in fixed, ordered positions, vibrating but not moving past each other; in a LIQUID, they're close but randomly arranged and can slide past one another; while in a GAS, they are far apart, move rapidly and randomly, and fill their container.
Samuel wants to make “elephant toothpaste” and knows one ingredient is hydrogen peroxide. From the list (Baking Powder, Yeast, Baking Soda, Sugar), pick one ingredient Samuel should test first and describe a simple test that would show it creates lots of foam with hydrogen peroxide.
Pick one and test it with hydrogen peroxide, notice if any foam is created. Then results in the chemical change because a new substance is forming.
Write one clear claim (one sentence) about how you can identify baking soda or baking powder using simple tests with vinegar and water.
Baking soda will react with vinegar but NOT water
Baking powder will react with vinegar and water.
Design a short experiment (3 steps) that would show conservation of mass when a visible change happens (for example, dissolving salt in water or mixing vinegar and baking soda in a sealed bag). Describe how you would measure and compare masses before and after to show mass is conserved.
weigh each item before the experiment, then weight after to prove that the mass is conserved.
Emi drops baking soda into vinegar in a container and places a balloon over the top. Predict what happens to the balloon and explain why using particle ideas
The Gas particles will be captured by the balloon and it will inflate. Particles will not disappear.
Explain, using words and a simple particle model, why adding more baking soda to vinegar (for example, two cups instead of one in the sealed bag) changes what happens inside the bag. Use the idea of reactants producing gas and how amounts affect the result.
More baking soda gives more reactant to make more gas; so bag would expand more; explain via particles — increased reactant amount produces more gas particles.
Choose one experiment from the assessment (lemonade weights, penny cleaning, vinegar + baking soda bag, powder tests, or elephant toothpaste design). Describe two different noticings (one about mass, one about appearance or gas production) that a scientist would record, and explain how these noticings help answer the scientific question.
answer will vary. must make sense and connect with discoveries made in the unit