Measurement & Units
Identify the correct unit for measuring mass in the lab.
What is grams (g)?
Is melting ice a chemical or physical change?
What is a physical change?
Which subatomic particle has a positive charge?
What is a proton?
How many particles are in 1 mole of a substance?
What is Avogadro’s number (6.02 × 10²³ particles)?
How many valence electrons does oxygen have?
What is 6 valence electrons?
Convert 250 cm to meters.
What is 2.5 meters?
Rusting iron is an example of what type of change?
What is a chemical change?
Which particle is found in the nucleus and has no charge?
What is a neutron?
Calculate the molar mass of H₂O
What is 18 g/mol?
What type of bond forms when electrons are shared?
What is a covalent bond?
How many significant figures are in 0.0450?
What is 3 significant figures?
Name one sign that a chemical reaction has occurred.
What is gas production, color change, temperature change, or precipitate formation? (any one)
What makes isotopes of an element different?
What is the number of neutrons?
How many moles are in 44 g of CO₂?
What is 1 mole?
(44 g ÷ 44 g/mol)
Draw the Lewis Dot Structure for sodium (Na).
What is one valence electron shown as one dot?
Calculate density if a substance has a mass of 30 g and a volume of 10 mL.
What is 3 g/mL?
(Density = mass ÷ volume = 30 g ÷ 10 mL)
Is dissolving sugar in water a chemical or physical change? Explain.
What is a physical change because no new substance is formed?
How many protons are in carbon-14?
What is 6 protons?
Find the average atomic mass given two isotopes and their abundances.
What is the weighted average of isotope masses?
How many valence electrons do elements in Group 17 have?
What is 7 valence electrons?
Convert 3.5 km to centimeters using dimensional analysis.
What is 350,000 centimeters?
(3.5 km → 3,500 m → 350,000 cm)
Explain the difference between chemical and physical changes.
What is a chemical change forms a new substance, while a physical change does not?
An atom has 17 protons and 18 neutrons. What is the isotope?
What is chlorine-35?
(17 protons + 18 neutrons)
How many molecules are in 0.75 moles of O₂?
What is 4.52 × 10²³ molecules?
(0.75 × 6.02 × 10²³)
Compare ionic and covalent bonding using electron behavior.
What is ionic bonds involve electron transfer, while covalent bonds involve electron sharing?