Practice Test 11 - Middle School Physical Science

20 questions. Answer them in any order, then submit to see your score and every explanation.

A student tests an insulated container. Criterion: Keep hot liquid above $60^\circ\text{C}$ for 4 hours. Test procedure: Pour $80^\circ\text{C}$ water into the container, close the lid, and measure the water temperature once per hour. Data: Hour 0: 80°C; Hour 1: 74°C; Hour 2: 68°C; Hour 3: 63°C; Hour 4: 59°C. Did the insulated container meet the criterion?
A baking soda and vinegar reaction is done in two ways. Closed system: baking soda in a balloon and vinegar in a flask. The balloon traps CO $_2$ . - Total mass before: 55 g - Total mass after: 55 g If the same reaction were done in an open system (no balloon, gas escapes), what would most likely happen to the measured mass on the balance, and why?
A student wants to test whether mass stays constant during a reaction that produces a gas. Which setup is best for showing conservation of mass using balance measurements?
A clear solution is made by mixing two colorless liquids. After a minute, the mixture turns yellow and gives off bubbles of gas. Which statement best connects these macroscopic observations to what happened at the particle level?
A teacher records a class concert. One recording is stored on cassette tape (analog) and another is stored as a CD (digital). Why has digital storage (like CDs) largely replaced analog tapes for storing and sharing music?
A student compares two sound waves traveling through air: - Wave P: small amplitude (quiet) - Wave Q: large amplitude (loud) Which piece of evidence best supports the claim that Wave Q carries more energy than Wave P?
Two identical metal spoons are placed in different cups of water. Spoon 1 is in ice water at $5^{\circ}\text{C}$ . Spoon 2 is in hot water at $60^{\circ}\text{C}$ . Spoon 2 feels much warmer to the touch. What does the higher temperature of Spoon 2 indicate about the particles in Spoon 2 compared with Spoon 1?
A product designer wants a renewable alternative to petroleum-based plastic for some packaging. Which natural resource could provide a renewable starting material for making some bioplastics?
A student tests a cold pack with these criteria: Criterion 1: Reach $0\text{–}5^\circ\text{C}$ within 2 minutes. Criterion 2: Stay below $10^\circ\text{C}$ for at least 30 minutes. Test procedure: Activate the pack and measure temperature with a thermometer. Data: At 2 minutes the pack is $6^\circ\text{C}$ . It reaches a minimum of $3^\circ\text{C}$ at 5 minutes. It stays below $10^\circ\text{C}$ until 40 minutes. Which criterion did the pack fail to meet?
In a sealed flask (closed system), 10.0 g of solution A is mixed with 15.0 g of solution B. A precipitate forms (a new solid appears). The mass of the sealed flask + contents is 128.6 g before mixing and 128.5 g after mixing (balance uncertainty ±0.1 g). What is the best conclusion?
A container shows particles close together but not in a regular pattern. Several medium-length arrows point in different directions, showing particles sliding past one another. What state of matter is shown?
A student pulls a wagon with a constant forward force on a level sidewalk. The wagon speeds up from a slow walk to a fast walk. Which statement best connects the force to the wagon's kinetic energy change?
A student pushes a book to the right across a table with a force of $15\,\text{N}$ . Friction on the book is $10\,\text{N}$ to the left. What is the net force on the book, and what will happen to its motion?
A student stands on a skateboard (low friction) holding a heavy ball. The student throws the ball forward (to the right). Before: student+skateboard and ball are at rest. During: the student pushes the ball right; the ball pushes the student left with an equal and opposite force. Which statement best predicts what happens to BOTH the ball and the student right after the throw?
A maglev train can float above its track instead of rolling on wheels. The train and track magnets are arranged so they push away from each other. How are magnetic forces used in this system?
Why can you count "5 molecules" in a diagram of water vapor (H $_2$ O) but you cannot count "5 molecules" in a diagram of a salt crystal (NaCl)?
A student wants to test: Which material insulates best—foam, plastic, or fiberglass? The student wraps three identical containers with the materials and fills them with the same hot water. What is the best way to reduce error when using only one thermometer?
A wave on a rope has an equilibrium (rest) position at $y=0\text{ m}$ . At one moment, the crest is at $y=+0.30\text{ m}$ . What is the amplitude of the wave?
A thermos uses a vacuum gap between two walls. Which statement best explains how the vacuum gap reduces heat transfer?
A 100 g sample of water takes 2 minutes to heat from $20^\circ\text{C}$ to $80^\circ\text{C}$ on a constant-power burner. Which statement best uses $Q = mc\Delta T$ to explain why 400 g of water takes longer to reach $80^\circ\text{C}$ on the same burner?

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