Experimental Design
This type of variable stays the same throughout the experiment.
What is a constant variable?
The number of protons in an atom.
What is the atomic number?
Ice melting. Physical or chemical?
Physical change
The charge of a neutron.
Neutral.
The dots in a Lewis Dot Structure represent what?
Valence electrons
The group that receives the independent variable.
What is the experimental group?
A mixture that is evenly distributed throughout.
What is a homogeneous mixture?
List two signs of a chemical change.
Formation of a precipitate, temperature change, gas, color change, odor change, something new is created (any two).
The subatomic particle that has no mass.
What is the electron?
Where are electrons located in the Bohr model?
Define extraneous variable. Name one extraneous variable that could affect plant growth if not controlled.
Extraneous variable:
The subatomic particle that determines bonding behavior.
What are valence electrons?
Is condensation endothermic or exothermic? Explain.
Exothermic because gas releases heat as it becomes liquid. Liquid molecules move slower than gas molecules.
The type of bond that forms by transferring electrons.
Draw a lewis dot structure for C.
Carbon with 4 dots around it evenly spaced.
Identify the IV and DV: “Does temperature affect how fast sugar dissolves?”
I.V: Temperature
D.V: Dissolving rate
Why is water (H₂O) considered a compound, not a mixture?
Because the atoms are chemically bonded in fixed ratios.
Why is a phase change NOT a chemical change?
Because the substance’s identity stays the same; only its state changes.
Which types of elements form covalent bonds?
Two or more non-metals.
If an atom has 11 protons and 12 electrons, what is it called?
Write a hypothesis correctly using the If…then…because… format (teacher approves).
Use this question: Does temperature affect how fast sugar dissolves? (For background research/prior knowledge use your phase of matter knowledge, and kinetic/thermal energy and particle movement knowledge)
If sugar is placed in hot water then it will dissolve faster than cold water because particle energy increases when heat (thermal energy) is added.
Explain the difference between solvent and solute. Provide one example.
Solvent = dissolves; solute = gets dissolved.
One possible ex: Gatorade mix (solute) in water (solvent)
Explain why dissolving salt in water is considered a physical change.
No new substance forms; the salt can be recovered by evaporation.
Explain why fluorine has more reactivity than neon.
Fluorine needs one more valence electron; neon has a full outer shell and is stable.
Explain why atoms with nearly full shells form different bonds than those with 1 valence electron.
Atoms bond to become stable; almost-full shells tend to gain/share electrons (nonmetals), low-shell atoms tend to lose/share electrons (metals).