Science Foundations
What type of observation is based on the five senses?
Qualitative
Which state of matter has a definite volume but no definite shape?
Liquid
Which subatomic particle has a positive charge?
Proton
What type of bond involves sharing electrons?
Covalent
What law states that matter is neither created nor destroyed?
Law of Conservation of Mass/Matter
Which variable is intentionally changed by the experimenter?
Independent variable
Is density a physical or chemical property?
Physical property
Which particle determines an element’s atomic number?
Protons
What type of bond forms between a metal and a nonmetal?
Ionic bond
In a chemical equation, where are the reactants found?
On the left side.
How should you smell a chemical directly in the lab?
Waft
Is salad dressing homogeneous or heterogeneous?
Heterogneous
What is an isotope?
Atoms of the same element with different numbers of neutrons
Why do atoms form chemical bonds?
To become more stable
What do coefficients represent in a chemical equation?
Number of molecules
Identify the independent and dependent variables: A student tests how temperature affects enzyme activity.
IV: Temperature, DV: Enzyme activity
How does particle motion differ between a solid and a gas?
Solids slightly vibrate in place; gases move freely and vibrate quickly
What element has 12 protons?
Magnesium
Why do noble gases rarely form compounds?
They already have a full shell of 8 valence electrons.
Balance the equation:
H₂ + O₂ → H₂O
2 H₂ + O₂ → 2 H₂O
Why is it important to keep constants the same in an experiment?
To ensure valid and reliable results.
A substance changes color and produces gas. Is this a physical or chemical change?
Chemical
Two atoms have the same atomic number but different mass numbers. Explain how this is possible.
They have different numbers of neutrons
Compare ionic and covalent bonding in terms of their electrons.
Ionic: electrons transferred; Covalent: electrons shared
Explain the biggest factor that increases reaction rate.
Higher temperature increases particle collisions.