Exam 2 Flash Cards

Combination reaction

A+B=C

Decomposition Reaction

C=A+B

Combustion Reaction

When burning compounds, the product ends up being CO2 and H2O.

Percent Composition

((number of atoms of the element)(atomic weight of the element))/FW of the substance

What is avogadros number?

6.02×10²³ atoms OR molecules

What do moles provide in terms of stoichiometric relationships.

A bridge from the molecular scale to real world scale.

GRAMS (MOLAR MASS) moles (AVOGADROS NUMBER) formula units

How do you determine empirical formula off of percentages?

Percentages= grams

Then equate each element to mols

Observe SMALLEST mols of an element

THEN calculate mole ratio by using this number to divide every other element’s mol (round to nearest whole number) then those are your subscripts

How to do basic stoichiometric equations and compare to different materials.

Grams of substance A (Molar mass of A) Moles Substance of A (use coefficients of balanced equations and watch units cancel) Moles of Substance B (Molar mass B) Grams of substance B

What is the limiting reactant?

The smallest reactant present.

What is excess reactant?

Present in stoichiometric equation after excess reactant is used up.

What is difference between theoretical yield and actual yield.

Theoretical yield is like the “what if” maximum yield while the actual yield is the yield YOU got.

Percent yield is ((actual yield)/(theoretical yield))