Vocabulary
Matter
Anything that has mass and takes up space.
What is the basic unit from which all matter is made?
What force does weight depend on?
The force of gravity.
Depending on the mass of the planet or moon in which an object is located, the force of gravity will be different and therefore, the weight of an object can change.
How are melting and carving an ice cube both examples of physical change?
Evaporation is an example of a physical change.
True!
Mixture
Made up of two or more substances that are together in the same place, but their atoms are not chemically bonded.
Heterogeneous!
Order from least dense to most dense:
Corn syrup: 1.33 g/ml
Honey: 1.36 g/ml
Water: 1.00 g/ml
Dish soap: 1.03 g/ml
Water, dish soap, corn syrup, honey
How are physical and chemical changes similar?
They both alter matter!
An object that is less dense than water will float.
True!
Density
A measure of the mass of a material in a given volume.
Is reactivity with oxygen an example of a physical or chemical property?
Chemical!
Why is it important for scientists to use the International System of Units (SI)?
It’s important for scientists to use the International System of Units (SI) so they can communicate results clearly and consistently with others around the world.
When a piece of paper burns, does it lose mass?
No, no mass is lost or gained during a change.
Law of conservation!
A compound is always a molecule.
True!
A type of molecule made from two or more different elements that are chemically bonded, that always has a fixed ratio.
Physical Change
A change that alters the form or appearance of matter but does not turn any substances in matter into a different substance.
Are odor, color, and solubility examples of physical or chemical properties of matter?
Physical!
A cube has the following measurements:
Length: 2 cm
Width: 2 cm
height: 2 cm
What is the volume?
8 cm3
The total energy of the motion of all of the particles in an object is known as...?
Thermal energy
When a liquid freezes, its mass and density both stay exactly the same.
False!
(The mass stays the same, but the density can change because the particles move farther apart or closer together.)
Chemical Change
A change in matter that produces one or more new substances.
Which of the following is a pure substance?
Table salt or sea salt?
Table salt.
Its composition is the same whether you are looking at a single grain of salt or a boulder of salt taken from a salt mine.
A graduate cylinder is filled with 15 ml of water. A unknown object was submerged into the cylinder and now the level is at 32ml. What is the volume?
17 ml
What type of change happens when thermal energy (heat) is absorbed?
Endothermic!
Burning a candle shows both a physical and a chemical change.
True!
(Wax melts — physical; wax burns — chemical.)