States of Matter & Phase Changes
What are the three states of matter?
solid, liquid, and gas
What is the equation for density?
d = m / V
What kind of property of matter can be observed with the senses?
A physical property
What kind of change keeps the composition of the substance the same after the change?
A physical change
What are the three subatomic particles of an atom called?
Protons, neutrons, and electrons
What phase change occurs when a solid turns into a liquid?
melting
What is the density of an object with a mass of 100 grams and a volume of 250 milliliters?
d = m / V = 100 g / 250 mL
d = 0.4 g/mL
What kind of property describes how the substance will react with another?
A chemical property
Phase changes (different states of matter) are examples of what kind of change?
Physical change
What is the center region of an atom called?
The nucleus
gas
What is the mass of an object with a density of 2 g/mL and a volume of 10 mL?
m = d x V = 2 g/mL x 10 mL
m = 20 g
Physical properties
Digesting food and metal rusting are examples of what kind of change?
Chemical changes
What does the atomic number represent?
The number of protons
What two phase changes involve cooling (taking heat away)?
freezing & condensation
What is the volume of an object that has a mass of 50 grams and density of 10 g/cm3?
V = m / d = 50 g / 10 g/cm3
V = 5 cm3
Flammability and toxicity are examples of what kind of property?
Chemical properties
Two liquids are combined and a solid precipitate is formed
Chemical change
What is the mass number of an atom with 7 protons, 7 neutrons, and 10 electrons?
mass number = p + n
7p + 7n = 14 mass number
What two phase changes can happen between a liquid and gas?
evaporation & condensation
What is the density of a block with a mass of 75 grams and the dimensions of 5 cm x 5 cm x 10 cm?
V = l x w x h = 5 cm x 5 cm x 10 cm = 250 cm3
d = m / V = 75 g / 250 cm3
d = 0.3 g/cm3
Solubility (how well it dissolves) and density are examples of what kind of property?
Physical properties
Sugar dissolved in hot coffee
Physical change
What is the charge of a Calcium atom with 19 electrons?
charge = p - e
20p - 19e = +1 charge