All About Matter 1
When atoms are arranged closely and vibrating, which phase of matter is represented?
Solid
When atoms are spread apart and moving freely, which phase of matter is represented?
Gas
Describe how particle motion and spacing differ between solids and liquids.
Solids: particles close together, vibrate in place; Liquids: particles close but move/slide past each other.
Define density in student-friendly language.
Mass of an item divided by its volume; sink or float
Identify whether boiling water is a physical change or chemical change and explain why.
Boiling water is a physical change since it's just a change in the state of the matter.
In 6-7 words, explain a closed system in a lab.
No way for matter to escape; all items contained for the reaction
State the formula for density using mass and volume.
D = mass divided by volume; (Remember, Density breaks your heart)
Define weight and state how it differs from mass.
Weight = gravitational force on an object; depends on local gravity; measured in Newtons.
Describe how to find the volume of an irregularly shaped rock so you can measure density.
Displacement
Where does Maxine weigh more; earth or venus and why?
Earth because the force of the gravitational pull is greater.
Describe one way temperature affects reaction rates or outcomes and give an everyday example.
Heat speeds up a reaction and causes a chemical change as evident in making toast, cooking an egg, baking a cake, etc.
Give two benefits and two limitations of scientific models as applied to atomic theory
simplify and visualize atomic behavior; allow predictions and experiments. Limitations: oversimplify scale/details; can mislead if treated as exact.
If an object has a mass of 120g on earth what would its mass be on the moon? Would its weight be the same in both locations? Explain your reasoning
Yes, the mass would be the same but the weight wouldn't. Mass remains constant while weight changes based on the force of the gravitational pull of the location.
A student observes bubbles when two liquids are mixed and notices the total mass decreases in an open container. Explain what likely happened and why the mass appears to have decreased.
gas escaped which had mass to it
Ryan has two objects; one with a density of 0.8 g/cm3 and the other with a density of 1.2 g/cm3. If an apple were to float and a tomato were to sink, which object is a tomato?
Tomato is the object with a density of 1.2 g/cm3
Raji has two different size rocks of gold. He believes that everything about them is different, but Tammy believes that why the objects have different masses that other properties remain the same. What are four properties that remain the same.
Conductivity, solubility, density, and melting point are independent of the amount of sample and stay the same when sample size changes.
Explain why melting point is considered a characteristic physical property and why it helps identify substances even if sample mass differs.
Answers will vary
Troy measured a metal with mass 67 g and volume 10 ml. Calculate its density.
6.7 g/ml
Jenna and Franklin have a combined mass of 200 kg on Earth and 200 kg on the Moon, but their combined weight is 402N on Earth and 67N on the Moon. Explain why their mass stays the same while their weight changes.
Mass is intrinsic and does not depend on gravity; weight depends on gravitational pull, which differs between Earth and Moon.
What does the law of conservation of mass state about the mass of reactants and products?
Before a chemical reaction, the mass of all the substances on the left side of the arrow is equal to the mass of all the substances on the right side.
Solid 2: Mass of 6.7 g, melting point of 607 degrees C, color is white
Solid 3: Mass of 7.6 g, melting point of 607 degrees C, color is white
could any of these be the same substance and why?
Solids 2 and 3 could be the same substance even though they do not have the same mass, they have the same melting point and color
If sodium (50 g) combines with chlorine (50 g) to form sodium chloride. Predict the mass of sodium chloride formed and explain using the Law of Conservation of Mass.
100 g because you have what you began with, nothing more and nothing less.
A student has two different liquids in open beakers. She pours the liquid from one beaker into the other beaker, and she observes bubbles. After the bubbling stops, she finds that the total mass of the liquids is now less than the total mass of the liquids before they were mixed together. How can her observation be explained?
Some of the liquid became gas and escaped the jar during the chemical reaction.
A mixture of iron filings and sulfur is heated to form iron sulfide. List at least three observable signs from an experiment that a chemical change has occurred, and explain how mass measurements in a closed system would illustrate conservation of mass.
Why would a scientist use a model to study DNA rather than studying the actual strand of DNA?
DNA is very small, so it is hard to study.