Matter – Building Blocks of Our Universe

N₂ + 3H_{2   =}  2NH₃

2Cu₂O + C = 4Cu + CO₂

4NO₂ + H₂O  = H + NO₃ + 3HNO₂

2H₂ + O₂   = 2H₂O

6CO₂ + 6H₂O   =  C₆H₁₂O₆ + 6O₂

N₂O₅ + H₂O = 2HNO₃

Virtual Laboratory Investigation

Problem: How do atoms and molecules of elements and compounds combine in chemical reactions?

 Atoms and molecules of different compounds combine by heat energy and electric energy.

 Research – Why do molecules stick together? What forces? Why can equations be balanced by coefficients and not subscripts? Define/explain equilibrium.

Molecules stick together because of equilibrium.

 The forces in the process are the force that combine to make a product, and the force that like to break apart and turn back to the reactants.

Equations can be balanced by coefficients because they tell how many molecules or atoms of this substance are involved in the reaction. Although these coefficients balance the equation, they do not change the content of the reaction. But by changing a subscript, which indicates number of atoms of the element in the compounds, you alter the equation.

 By definition, equilibrium is the state of a chemical reaction in which its forward and reverse reactions occur at equal rates so that the concentration of the reactants and products does not change with time. But breaking it down, it consists of these two ideas: (1) Two reactants combine to make a product. (2) Products like to break apart and turn back into the reactants. (3) There is a point where those two reactions happen and you can't tell that any reactions are occurring. That point is when the overall reaction is happy. There is no pressure to do more of one thing, or another.     

 Materials

Hopkins, Jean, et al. Matter: Building Block of the Universe. 2nd ed. Vol. N. Englewood Cliffs, New Jersey: Prentice-Hall, 1994. 1-172.

Chem4Kids. 1997. Andrew Rader Studios. 11 Dec. 2002 <http://chem4kids.com/files/react_equilib.html>.

Conclusion – Why do equations need to balance?

Equations need to balance because in order to have a true chemical equation, there must be the same number of atoms in each element on each side of the equation.

 2H₂ + O₂ = 2H₂O