Chemical Reactions
Give 4 pieces of evidence that indicate a chemical reaction has occurred.
Bubbling, color change, temperature change, new substances formed.
This evidence of chemical change may be seen as bubbles in a liquid, where _____ forms.
A gas forming
The materials at the beginning of a chemical reaction
Reactants
What is element abbreviated with Hg? What is it's atomic number?
Mercury, 80
In the chemical formula for the reaction between NaHCO3 and HCl, what is the chemical name for the gas that is produced?
Carbon dioxide.
Two or more substances that are combined but can be separated
Mixture
This evidence of chemical change is called a precipitate, where a ______ forms
Solid forming
The NEW material(s) formed at the end of a chemical reaction
Products
What is a particle? Give a SPECIFIC example?
The smallest piece of a substance that is still that substance, atoms are particles
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!
A well mixture where one of the substances are mixed at the particle level
Solution
This is the KEY characteristic of a chemical reaction
A NEW substance forming
This law states that the total mass of the reactants is equal to the total mass of the products
Law of the Conservation of Matter (Mass)
What is an element? Give a SPECIFIC example.
A fundamental substance that cannot be broken into simpler substances by chemical or physical processes
How many atoms, how many elements, and which elements make up H2O (or water)?
Atoms - 3
Elements - 2
Element names - hydrogen, oxygen
What happens to atoms when a chemical reaction occurs?
They rearrange into new substances. (are not created or destroyed)
This type of evidence of chemical change may include an increase OR a decrease
Temperature change
Consider the following chemical equation
2CuO + C ⇒ 2Cu + CO2
What is the number of Cu atoms on each side of the equation
2
What is a compoud? Give a specific example.
A substance defined by a particle composed of two or more different atoms, H2O, NaCl, etc
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
True or false: A chemical reaction always occurs when substances combine.
False!
When sugar turns from white to brown it is burning, which is a type of __________ chemical reaction
Combustion
Consider the following chemical equation
6CO2 + 6H2O ⇒C6H12O2 + 8O2 + energy
These elements involved in this chemical equation
Carbon, Hydrogen, and Oxygen
What is the difference between dissolving and melting? Give an example of each
Dissolving requires two substances, melting requires one. Melting requires a change in temperature, while dissolving does not.
Write an example of a chemical reaction on the whiteboard with the correct reactants and products.
Multiple answers accepted