Chemical Reactions Lab

Paige, Julie, Caleb, Evan

  1. Introduction

Definition of chemical reactions


  • Reactants- Any substance that undergoes a chemical change in a reaction
  • Products- A substance obtained from another substance through chemical change
  • Coefficients- A number that is constant for a given substance


b. Signs of a chemical reaction:

Bubbles - Reaction creating a gas

Color change

Precipitate is formed

Temperature change


B. Analysis of Reactions

Experiment 1: copper (II) sulfate pentahydrate crystals decompose to form copper (II) sulfate and water.

  1. The evidence that we saw that led us to believe it was a chemical reaction was the changing of color and a new chemical was formed after setting it on fire; also its not reversible.



b. The definition for hydrate is a substance formed when water combines with another substance.


c. Decomposition


d. CuSO45H2O -> CuSO4 + 5H2O


Experiment 2: Potassium iodide reacts with lead(II) to yield lead iodide and potassium

We put a little bit of potassium iodide into a test tube, and added a few millimeters of lead(II) nitrate solution.

Observations: The mixture turned a neon yellow.

Bubbles were formed and it looks “chalky”

-We believe this was a chemical reaction because bubbles were formed, and bubbles is an indication of a chemical reaction.

Balanced Equation: 2KI + Pb(NO3)2 -> PbI2 + 2KNO3

Experiment 3:Magnesium reacts with oxygen gas to form...


Observations: Light a white bright color

  1. It was a chemical reaction because light and heat was emitted

Observations: Emitted a bright white light when burnt

Shattered when it was done burning

b. That oxygen is a lone element that has 2 atoms when by itself


c. Combustion


Equation:


Experiment 4:Zinc metal reacts with hydrochloric acid to produce…

  1. We think it was a reaction because bubbles were emitted and it created a flammable gas
  2. Cation- an Ion with a positive charge

Anion- an Ion with a negative charge

c. Single replacement


Equation


d. Hydrogen gas


Experiment 5:Hydrogen peroxide breaks down to form water and oxygen gas.

  1. Bubbles were formed, a new substance was created and its irreversible
  2. Catalyst- A substance that speeds up a chemical reaction
  3. Equation:
  4. The oxygen gas igniting or providing fuel for the glowing splint







C. Conclusion


  1. Identify the following as Physical or Chemical changes
  • i. Dissolving Salt in Water- Physical
  • ii. Melting Ice- Physical
  • iii. Milk Turning Sour- Chemical
  • iv. Burning Fireworks- Chemical
  • v. A 2-Liter Bottle Going Flat- Chemical
  • vi. Frying an Egg- Chemical




Symbol

What it means

Experiment #

Chemical used



(s)

Solid State

#3

Magnesium



(l)

Liquid State





(g)

Gaseous State

#5

Oxygen