Reactions
Give 4 pieces of evidence that indicate a chemical reaction has occurred.
Bubbling, color change, temperature change, new substances formed.
The phase of matter in which the particles travel the fastest and the farthest apart.
Gas!
What is a substance? Give a SPECIFIC example.
A type of matter defined by a unique particle. Examples: elements or compounds O, H2O, He, NaCl...
In the chemical formula for the reaction between NaHCO3 and HCl, what is the chemical name for the gas that is produced?
Carbon dioxide.
What is a chemical reaction?
When starting substances (reactants) change into new, different substances (products).
The phase of matter in which an object will melt.
Solid!
What is a particle? Give a SPECIFIC example?
Atoms are particles. O, H2O, He, NaCl...
The smallest piece of a substance that is still that substance
True or false: In a chemical formula (or chemical equation) the number of atoms in the reactants MUST match the number of atoms in the products.
True!
What happens to atoms when a chemical reaction occurs?
They rearrange into new substances. (are not created or destroyed)
The phase of matter in which an object will sublime.
Solid!
What is an element? Give a SPECIFIC example.
A fundamental substance that cannot be broken into simpler substances by chemical or physical processes
He, O2, Na...
How many atoms, how many elements, and which elements make up H2O (or water)?
Atoms - 3
Elements - 2
Element names - hydrogen, oxygen
True or false: A chemical reaction always occurs when substances combine.
False!
What happens to the particles in a solid block of lead as it melts?
The kinetic energy of the particles increases until the bonds are broken and the lead particles spread apart, moving around each other like a liquid.
What is a compound? Give a SPECIFIC example.
A substance defined by a particle composed of two or more different kinds of atoms. H2O, NaCl...
What are the reactants in the chemical equation that describes what happens when calcium carbonate and hydrochloric acid are combined? Give the answer with an atomic model.
CaCO3
2HCl
Write an example of a chemical reaction using hydrogen and oxygen as the reactants.
H2 + O2 = H2O
What happens when a volume of air is heated in a closed balloon?
The air particles move faster, the air particles hit each other more frequently, the air particles get farther apart, and the air particles occupy more space.
What is the difference between dissolving and melting?
Give examples of dissolving and melting.
Dissolving requires two substances while melting requires only one.
Dissolving sugar into water makes sugar water vs. melting butter on the stove.
Write an example of a chemical reaction on the whiteboard with the correct reactants and products.
See NBK