Reactants & Products
What are the substances you start with in a chemical reaction called?
Reactants
What is one sign that a chemical reaction has occurred?
Color change
What is the smallest unit of an element?
Atom
Is baking a cake a physical or chemical change?
Chemical Change
What must be the same on both sides of a chemical equation?
The number of each type of atom
What are the substances you end up with called?
Products
When bubbles form, what does that show?
A gas is produced
What is a molecule made of?
Two or more atoms bonded together
When metal rusts, what kind of change is it?
Chemical Change
The first part of a balanced chemical equation is shown: Cu +2AgNO3 → ______________. In order for this equation to be balanced, how many oxygen (O) atoms must be present in the products?
6
In the reaction H₂ + O₂ → H₂O, what is the product?
Water
What does it mean if a reaction gives off light or heat?
Energy change occurred
True or False: Chemical reactions create new atoms.
False
When ice melts, is that a chemical reaction?
No, Physical Change
In the equation 2H₂ + O₂ → 2H₂O, how many hydrogen atoms are on each side?
4
True or False: Reactants and products are made of different atoms.
False — same atoms, just rearranged
What can Change from a liquid to gas?
water evaporating
Hydrogen (H) and oxygen (O) are pure substances. Each is made of only one type of atom, but hydrogen atoms are different from oxygen atoms. Hydrogen and oxygen chemically combine to form water (H2O).
Based on this information, which statement is true?
A. Hydrogen, oxygen, and water are all elements.
B. Hydrogen, oxygen and water are all molecules.
C. Hydrogen and oxygen are elements, and water is a molecule.
D. Hydrogen is an element and oxygen and water are molecules.
Hydrogen and oxygen are elements, and water is a molecule.
Why is digestion considered a chemical reaction?
Food is broken down into new substances
Which of the following represents a molecule?
A. Ca
B. Co
C. CO
D. Cu
CO
Explain what happens to atoms during a chemical reaction.
They are rearranged to form new substances.
List three signs of a chemical reaction.
Color change, gas production, temperature change, precipitate, light
What happens to the atoms in a chemical reaction?
They rearranged
Give one example of a chemical reaction you see at home.
cooking, burning, items rusting
A molecule of H2SO4 contains how many atoms?
7