Elements and the periodic table
True or False: All particles are atoms but not all atoms are particles.
False, all atoms are particles, not all particles are atoms.
Fill in the blank:
When two or more non-metal atoms are joined by chemical ___ they form a molecule.
bonds
True or False: The reactants are new substances that are formed and products are the starting materials.
False, the reactants are the starting materials that react with each other and the new substances are the products.
Do chemical changes form new substances?
Yes
Explain why a gas being produced is not always a sign that a chemical change is taking place.
it might also be a physical change such as evaporation or sublimation.
What is the correct way to write the chemical symbol for Iron. (20 second time limit).
a) Ir b) Fe c) FE d)fe
b) Fe
What is the difference between an element and a compound?
Element - only contains one type of atom
Compound - contains two or more different elements that are chemically bonded together.
What does the law of conservation mass state?
That matter can neither be destroyed or created, but can be rearranged into ne substances.
Identify the option that represents a chemical change and explain your answer:
A) XY --> XY
B) XX --> XX
C) YY --> YY
D) XY --> X + Y
D) XY were joined together in the reactants, X and Y are not bonded in the products
Identify if the following are chemical or physical changes:
a) ice melting to water
b) cooking a pizza
c) fireworks exploding
d) breaking a plate
a) physical
b) chemical
c) chemical
d) physical
Determine what type of atoms are in each of the following molecules, and how many of each are there:
a) Nitrogen (N2)
b) Oxygen (O2)
c) Ozone (O3)
a) 2 nitrogen atoms
b) 2 oxygen atoms
c) 3 oxygen atoms
What is the term for a solid that dissolves in a liquid to form a solution?
Solute
Why is a change of state (like freezing or boiling) considered a physical change?
Because no new substance (product) is formed; it's still the same substance in a different state (the particles are moving faster or slower)
Which of the following observations would NOT be considered a sign of a chemical change?
A) noticing a solid forming
B) seeing a substance catch fire
C) cutting a solid into smaller pieces
D) seeing permanent colour change
C) Cutting a solid into smaller pieces.
Identify the reactants and the products in the following word equation:
methane + oxygen --> carbon dioxide and water vapor
Reactants: methane and oxygen
Products: carbon dioxide and water vapor
What are the 3 main parts to an atom and what are their charges?
Neutron (No Charge)
Proton (+)
Electron (-)
Explain why a chemical formula cannot be written for a mixture
A mixture is made up of different substances, so a single formula cannot be written for it.
Identify 2 examples of physical change and 2 examples of chemical change that you might observe at home.
Physical changes - icecream melting, water boiling.
Chemical changes - toast burning, cake baking, egg frying.
What happens to bonds in chemical change? (Try using terms reactants and products)
The bonds in the reactant are broken, and new bonds are formed in the products.
Is the following equation balanced or unbalanced?
6CO2 + 5H2O --> C6H12O6 + 6O2
Unbalanced.
Would you use a metal or non-metal for the following application and justify a response.
a) the element in a heater
b) a fishing rod
c) an oven mitt
a) metal - it needs to conduct electricity and heat
b) non-metal - it needs to be light and flexible (not bend permanently
c) metal - it should not conduct heat
Can a compound exist in a mixture? Explain.
Yes, it is only if the compounds are not chemically bonded that is considered a mixture.
If salt dissolves in water and the mixture looks different, how can you prove it’s still a physical change and not a chemical one?
You can evaporate the water and recover the salt, showing that no new substance was created — just a mixture formed.
Why does cooking an egg count as a chemical change, even though no new substance is visible?
Cooking an egg is a chemical change because proteins denature and new substances form; it’s irreversible.
Using the particle model explain the difference between solid, liquid and gas. (diagram)
In solids, particles are tightly packed in a fixed, ordered arrangement, allowing only vibrations. In liquids, particles are still close together but are randomly arranged, sliding past each other. In gases, particles are widely separated, move rapidly and randomly, and have no fixed volume or shape