CHAPTER 10 ASSESSMENT - CONCEPTS
What is the Celsius equivalent of 100K?
-173 degrees C
Convert -20 degrees C to the Kelvin scale.
253 K
Why doesn't a solid flow?
A solid doesn't flow because the molecules are locked into place by intermolecular forces. The molecules can vibrate in place, but cannot move around to allow the solid to flow like a liquid or gas.
What is the difference between 0 degree on the Celsius scale and absolute zero?
Absolute zero ( 0-K; -273 degrees C ) is the coldest temperature matter can get. The temperature 0 degree C ( 273-K) is when water freezes.
Explain the difference between an atom and a molecule.
An atom is the smallest particle of an element that retains the properties of that element. A molecule is made of two or more kinds of atoms and is the smallest particle of a compound that retains the properties of that compound.
Explain the differences between elements and compounds.
An element is made up of only one type of atom. A compound is made of two or more elements chemically combined.
What is Brownian motion? How does it provide evidence that matter is made of atoms and molecules?
Brownian motion, THE JERKY MOVEMENT OF SMALL PARTICLES LIKE DUST PARTICLES IN THE AIR, PROVIDES EVIDENCE THAT THOSE PARTICLES ARE COLLIDING WITH PARTICLES THAT ARE TOO SMALL TO SEE (ATOMS OR MOLECULES). The jerky motion is caused by the much smaller atoms and molecules in the air colliding with the larger dust particles.
Calculate the average human body temperature, 98.6 degrees F, on the Celsius scale.
C = 5/9 ( F - 32 ) C = 5/9 ( 98.6 - 32 ) C = 5/9 ( 66.6 ) C = 333/9 C = 37 C
Explain the difference between the two kinds of substances.
Elements are made of only one type of atom while compounds are made of two or more types of atoms, chemically combined into molecules.
How can the Fahrenheit and Celsius scales be converted from one to another?
F = 9/5 *C + 32 C = 5/9 ( F - 32 )
Describe a method you would use to separate chicken soup into other forms of matter from which it is made.
First, strain the soup and sort the large particles. Next use filter paper to separate even smaller particles. Finally, boil the soup to evaporate the water, leaving behind salt and other compounds. It would be difficult to separate the compounds left behind.
Name one similarity between gases and liquids.
Gases and liquids can flow.
Name three foods that would be classified as heterogeneous mixtures, and three foods that are homogeneous mixtures.
Heterogeneous mixtures: rocky road ice cream, salad, beef stew. Homogeneous mixtures: cola, lemonade, spring water
Explain how a liquid can enter the gas phase without reaching its boiling point.
In a liquid, some of the molecules occasionally break free of the intermolecular forces and escape into the air. This process is called evaporation.
A liquid takes the shape of its container, but why doesn't a liquid expand to fill the container completely?
Intermolecular forces still exist in a liquid although they are weaker than in a solid. This prevents molecules from breaking completely apart, allowing the liquid to expand and fill its container like a gas.
Since it is fairly easy to tell when the temperature is high or low, why do we need thermometers, thermistors, and other devices for measuring temperature?
People cannot consistently and accurately distinguish between hot and cold. To be able to accurately measure temperatures, people need to use instruments that use a measurable quantity such as electrical resistance, color change or change in length to compare temperatures.
What is the most common phase of matter in the universe?
Plasma are the most common phase of matter in the universe.
Which has more thermal energy: gas, plasma, or liquid?
Plasmas have the highest thermal energy.
What are the two major categories of matter?
The two major categories of matter are pure substances and mixtures.
Absolute zero is considered the lowest possible temperature. What is the highest possible temperature?
There is no practical limit to how big temperatures can get.
A pizza box says to bake the pizza at 450 F but your oven measures temperature in Celsius. At what temperature should you set the oven?
You should set it to about 230 C ( exactly 232 )
Compare the Celsius temperature scale with the Fahrenheit scale by answering the following questions. a. Which is the larger change in temperature, 1 degree C or 1 degree F? b. What are the freezing points and boiling points of water on C and F scale? c. Why are two different scales used?
a. A Celsius degree represents a greater change in temperature than a Fahrenheit. b. Celsius: freezing point = 0 degree C boiling point = 100 degrees C Fahrenheit: freezing point = 32 degrees F boiling point = 212 degrees F c. The Fahrenheit scale was established first and is still used in the U.S. The Celsius scale, which is a metric scale, is used in most other countries and has values ( like 0 degree C and 100 degrees C ) which are easier to remember.
Identify each of the following in your classroom, school cafeteria, or home: a. five homogeneous mixture b. five heterogeneous mixture c. three elements d. five compounds
a. Homogeneous mixtures: soda, water from the drinking fountain, ketchup, saline solution, and air. b. Heterogeneous mixtures: spaghetti and meatballs, chocolate chip ice cream, granite, trail mix, mild c. Elements : copper, helium, mercury d. Compounds: salt, sugar, gasoline, water, rust
Compare the Celsius temperature scale with the Kelvin scale by answering the following questions: a. Which is the larger change in temperature, 1K or 1 degree C? b. What are the freezing points and boiling points of water on each scale? c. Why are tow different scales used?
a. They are the same. b. 0 degree C is the freezing point and 100 degrees C is the boiling point of water on the Celsius scale. 212 K is the freezing point and 373 K is the boiling point of water on the Kelvin scale. c. The Kelvin scale is useful because it starts at absolute zero. A temperature in Kelvins measures the actual energy of molecules relative to zero energy. The Celsius scale is more commonly used and understood because it used by both scientists and regular people in most countries.
About 70 percent of the Earth's surface is covered by water. There is water underground, and even in the atmosphere. What is water's state at each of the following temperatures? a. temperatures below 0 degrees C. b. temperatures between 0 and 100 degrees C. c. temperatures above 100 degrees C.
a. solid b. liquid c. gas
Identify the phase represented by each diagram below and describe its basic properties.
a. solid: maintains its shape and volume b. liquid: maintains volume, flows easily c. gas: fils its container, flows easily
Describe a method you would use to separate a mixture of sugar and water.
boil the mixture and collect the water in a condenser. Sugar crystals would be left behind.
What is sublimation?
the process in which a solid changes directly into a gas
