Scientific Inquiry
A statement that can be tested by experiments and is based on prior knowledge and observations.
Hypothesis
The smallest unit of matter that still retains the properties of an element.
Atom
Water is made of two hydrogen atoms and one oxygen atom. The bonds between them are what type of covalent bond?
Polar covalent bond
Adding an acid to water increases the number of these ions.
H⁺ (hydrogen ions)
Which type of bond gives water its unique properties?
Polar covalent bond
In an experiment, this variable is deliberately changed or manipulated.
Independent variable
This type of bond forms when one atom gives up electrons and another atom takes them, forming ions.
Ionic bond
Unlike most substances, water becomes less dense when it does this.
Freezes
Substances with a pH greater than 7 are called what?
Bases
What is the difference between a scientific theory and a scientific law?
Theory: Explains why things happen (well-tested explanation).
Law: Describes what happens (a rule/pattern, often mathematical).
Recorded measurements that involve numbers, such as length or weight, are called what type of data?
Quantitative data
What do we call an atom’s outermost electrons, and why are they important for bonding?
Valence electrons; they determine how atoms bond with others.
Because of hydrogen bonding, water molecules stick to each other. This property is called what?
Cohesion
A solution with a pH of 2 has how many times more H⁺ ions than a solution with a pH of 5?
1000 times more
How are isotope numbers determined?
The sum of protons and neutrons in the nucleus
What do we call the group in an experiment that does not receive the independent variable and is used for comparison?
Control group
The sum of protons and neutrons in the nucleus is called what?
Mass number
What property of water explains why it forms droplets and has a “skin” on its surface?
Surface tension (from cohesion)
What process happens when an acid and base combine to form a solution closer to pH 7?
Neutralization
Give two examples of how hydrogen bonding in water benefits life on Earth.
Cohesion → helps plants transport water (capillary action)
High specific heat → stabilizes climate
Ice floats → insulates aquatic ecosystems
Evaporative cooling → regulates body temperature
In an experiment, why is it important to keep controlled variables the same?
To ensure only the independent variable affects the results
An atom that donates electrons in a bond is called this.
The cation
Why does water take longer to heat up and cool down compared to most other substances?
Because of its high specific heat due to hydrogen bonding
A solution has 1,000 times more OH⁻ ions than pure water. Is it acidic, neutral, or basic?
Basic
in what shape do water molecules arrange themselves as they begin to freeze?
Crystal lattice