Describing Matter
Which one is a physical property of an element?
ability to tarnish or color
color
What is the unit for measuring volume?
cubic centimeter or milliliters
the force that holds two atoms together
What is chemical bond?
The energy of matter in motion
What is kinetic energy?
Group of atoms that are joined together by chemical bonds
What is molecule?
A homogeneous mixture that is evenly mixed (i.e. lemonade, hot cocoa)
What is a solution?
Define mass
measurement of the amount of matter in an object
Give an example of a chemical change?
combustion, burning a fuel, baking, a chemical reaction, etc
Chemical and Physical changes includes changes in...
energy
What is energy and give an example?
is the ability (capacity) to do work or cause change.
example: student's answer
Atoms are composed of molecules or molecules are composed of atoms. Which statement is not true?
atoms are composed of molecules
What is the formula to find the density of an object?
divide mass by its volume
what changes in a substance when it undergoes a chemical change?
What is the difference between endothermic and exothermic changes?
endothermic change absorbs energy and exothermic change releases energy
Ice is an example of what state of matter? Give 3 more examples of such state of matter
Solid, student's answers.
What is an element? and How is that different from a compound?
a pure substance that cannot be broken down into any other substances by chemical means. Compounds are also pure substances, but they are composed by 2 or more elements
What would happened to a solid block, whose density is less than 1 g/cm3 if it is placed in a container of water?
it will float because its density is less than the density of water
Give 5 examples of physical changes that you observe in your house and explain why they are physical changes?
Student's answer
Define temperature and compare and contrast with thermal energy
temperature is the measure of the average energy of random motion of particles of matter; thermal energy is the total energy of all the particles in an object. One is the average energy of the particles that are moving, the other is the total of all particles in the object.
Calculate the density of alcohol if you have 10 grams of alcohol and its volume is 12.7 cm3
density = mass/volume
density = 10.0 g/12.7 cm3
density= 0.79 g/cm3
Define what a compound is and mention two characteristics of compounds
Compound is a pure substance made of two or more elements.
A compound can be represented by a chemical formula.
A compound has different properties from the elements that formed it.
What is the difference between weight and mass? What measurement would change if you were to travel to the moon, mass or weight? Explain why
Weight is a measure of the force of gravity on matter. Mass is the amount of matter. Weight would change in the moon because there is less gravity there.
State the Law of Mass Conservation and give an example of this.
Matter is not created or destroyed in any chemical or physical change.
Example, student answer
Describe the energy transformations that occur when a person pushes a bike to the top of a hill and rides down.
Potential energy increases as the person pushes the bike up to the hill. Potential energy becomes kinetic energy when the persons rides the bike down the hill.
Explain the difference between a homogeneous and a heterogeneous mixture. Give three examples of each.
In a homogeneous substances in a mixture are so evenly mixed that you can't see the different parts. In a heterogenous mixtures substances are separated and you can see the different parts.
Example student's answer