Describing Matter
Chemistry is
a. the study of matter and how it changes
b. the study of elements
c. the study of living organisms
d. the study of energy
a. the study of matter and how it changes
A substance that cannot be broken down into any other substances by chemical or physical means
What is an element?
The SI unit of mass
What is a kilogram (kg)?
Which of the following is a physical change?
a. burning b. rusting
c. freezing d. oxidation
c. freezing
Physical property or chemical property:
State of matter
Physical property
Anything that has mass and takes up space
What is matter?
Shows the elements and ratio of atoms in a compound
What is a chemical formula?
The amount of space that matter occupies.
What is volume?
Which of the following is NOT a chemical change?
a. leaves turning color
b. fruit ripening
c. silver tarnishing
d. food coloring dissolving in water
d. food coloring dissolving in water
Is it a compound, element, or mixture:
salt
A compound
A characteristic of a substance that describes its ability to change into different substances.
Which of the following is an example of a chemical formula:
a. H2O b. CO
c. NH3 d. All of the above
d. All of the above
What is the difference between weight and mass?
Weight is a measure of the force of gravity on an object, while mass is the amount of matter in an object. Weight may change depending on where you are, but mass stays the same no matter where you are.
The fact that matter is neither created nor destroyed in any physical or chemical change
What is the law of conservation of mass (matter)?
What is the equation for density?
(double points if you can give the SI units too)
Density = mass (g)/volume(cm3)
Which of the following is an example of a chemical property?
a. density b. flammability
c. hardness d. luster
b. flammability
What is the difference between a homogeneous mixture and a heterogeneous mixture?
A homogeneous mixture is uniform throughout the mixture and cannot easily be separated. (i.e. sugar in water)
A heterogeneous mixture is not uniform throughout the mixture and can easily be separated. (i.e. salad)
After an object is dropped into a container of water is comes to the surface and floats. What can you say about its density?
The object is less dense than water, causing it to float in the water.
What is the difference between an endothermic change and an exothermic change?
An endothermic change is a change in which energy is absorbed.
An exothermic change is a change in which energy is released.
Physical change or chemical change:
roasting a marshmallow
Chemical change
Name 2 examples of a physical property.
Examples: color, texture, hardness, state, density, conductivity, etc.
What is the difference between a mixture and a compound?
A mixture is made up of 2+ substances that are together in the same place, but their atoms are NOT chemically bonded.
A compound is a substance made of 2+ elements that are chemically combined in a set ratio.
A rectangular box has a length of 5 cm, a width of 3 cm, and a height of 2 cm. What is the volume of the rectangular box? (make sure that you use proper units in your answer)
The volume of the rectangular box is 30 cm3.
What is the difference between temperature and thermal energy?
Temperature is the measure of how hot or cold something is; it is related to the energy of motion of the particles of matter.
Thermal energy is the total energy of the motion of all of the particles in matter. The larder something is, the more thermal energy it has.
Give an example of an endothermic and an exothermic change.
Endothermic: ice melting, cooking/baking, evaporation, boiling water, etc.
Exothermic: lighting a match, explosions, rusting iron, burning a candle/ leaves/ sugar, etc.