Chemical Reactions
Which reaction needs energy to get started? Endothermic or exothermic?
Endothermic
What comes out of a chemical reaction?
Products
How many Carbons are there in NaHCO₃?
1
Which of the following is an example of a chemical change: splitting wood, melting ice, burning wood or dissolving salt in water.
Burning wood
How is CO different from CO2?
CO only has one C and one O atom
CO2 has one C atom and two O atoms
On the Periodic Table which element has the symbol Au?
Gold
A substance that enters a chemical reaction is called this.
reactant
In the formula 6H2O, How many water molecules are present?
6
All of the following are examples of chemical change except:
Increase in temperature, release of light, formation of a solid, melting of ice
Melting ice
State the Law of Conservation of Mass.
matter can not be created nor destroyed, just rearranged
This type of reaction releases energy/heat.
What is exothermic?
hydrogen + oxygen → water
Where are the reactants in this chemical reaction?
How many oxygen are in 2C6H8O7
14
Color, texture, bending, tearing, melting, boiling, dissolving are all examples of this.
Examples of a physical change
a pure substance made by chemically combining two or more elements; represented by a chemical formula
Compound
The atomic number of an element is its __________.
Number of protons
In a chemical reaction the substances to the right of the arrow are called this/these?
What are products?
In the formula 5CaSO4,how many oxygen atoms do we have?
20
Give three examples that a chemical change has taken place.
What is temp. change, color change, odor change, formation of a precipitate, formation of a gas?
Is this equation a balanced or not balanced chemical equation?
P4 + O2 → P4O6
Not Balanced
A pure substance composed of the same type of atom throughout
Element
Is this a balanced or not balanced equation?
H2S + NaCl → HCl + Na2S
Not balanced
How many Aluminum atoms do we have in the products?
Al + O2 → Al2O3
2
What two things can never happen to atoms in a chemical reactions?
Atoms cannot be created or destroyed in a chemical reaction
The process in which the building blocks of matter (atoms) are rearranged to produce different substances.
What is the definition of a chemical reaction?