CHEM 121 UNR EXAM 2025/2026 QUESTIONS WITH
ANSWERS GRADED A+
✔✔Finding Empirical Formula - ✔✔1)assume we have 100g
2)convert to grams
3) divide by lowest number
✔✔Limiting Reactant - ✔✔the element that determines the reaction
✔✔solution - ✔✔a homogenous mixture of 2 or more substances
✔✔solvent - ✔✔the one that is in abundance
✔✔solute - ✔✔the one being dissolved
✔✔electrolyte - ✔✔any solute that dissolves in water that can conduct electricity
✔✔non-electroyte - ✔✔doesn't conduct electricity
✔✔Strong Electrolytes - ✔✔Strong acids
strong bases
salts
completely dissolves
✔✔Weak Electrolytes - ✔✔Weak acids
weak bases
partially dissolves
✔✔Non Electrolytes - ✔✔sugars
doesn't dissolved
✔✔Metathesis Reaction - ✔✔double displacement
AB(aq) + CD(aq)-----> AD+CB
✔✔Chemical equation - ✔✔normal equation
✔✔complete ionic equation - ✔✔separate everything into its ions
✔✔net equations - ✔✔does not include spectator ions
✔✔spectator ions - ✔✔ions not included in the reaction
✔✔neutralization RXN - ✔✔Acid+Base----> salt water
, ✔✔Monoprotic acid - ✔✔donates 1 hydrogen
✔✔diprotic acid - ✔✔donates 2 hydrogen
✔✔triprotic - ✔✔donates 3 hydrogens
✔✔Acid properties - ✔✔proton donors
tastes sour
corrosive
✔✔base properties - ✔✔proton acceptors
tastes bitter
caustic
✔✔Oxidation - reduction Reactions - ✔✔swapping electrons
✔✔OILRIG - ✔✔O-xidation
I-s
L-oss
R-eduction
I-s
G-ain
✔✔exothermic reaction - ✔✔A+B----> C+Heat (-) Heat:-#
✔✔endothermic reaction - ✔✔Heat+A+B----> C (+) Heat:+#
✔✔Energy - ✔✔capacity to do work
✔✔1 Calorie - ✔✔=4.184 J
✔✔System - ✔✔chemical RXN/Product/Solvent
✔✔Surrounding - ✔✔everything else
✔✔degrees C to Degrees K - ✔✔K=C+273.15
✔✔Hess's Law - ✔✔a) flipping a rxn changes the sign of Change H
b) multiplying by a coefficient means multiplying Change H by the same coefficient
c) add all changeH's at the end
✔✔Standard Heat of Formation - ✔✔elements in natural form
ΣHproducts - ΣHreactants
ANSWERS GRADED A+
✔✔Finding Empirical Formula - ✔✔1)assume we have 100g
2)convert to grams
3) divide by lowest number
✔✔Limiting Reactant - ✔✔the element that determines the reaction
✔✔solution - ✔✔a homogenous mixture of 2 or more substances
✔✔solvent - ✔✔the one that is in abundance
✔✔solute - ✔✔the one being dissolved
✔✔electrolyte - ✔✔any solute that dissolves in water that can conduct electricity
✔✔non-electroyte - ✔✔doesn't conduct electricity
✔✔Strong Electrolytes - ✔✔Strong acids
strong bases
salts
completely dissolves
✔✔Weak Electrolytes - ✔✔Weak acids
weak bases
partially dissolves
✔✔Non Electrolytes - ✔✔sugars
doesn't dissolved
✔✔Metathesis Reaction - ✔✔double displacement
AB(aq) + CD(aq)-----> AD+CB
✔✔Chemical equation - ✔✔normal equation
✔✔complete ionic equation - ✔✔separate everything into its ions
✔✔net equations - ✔✔does not include spectator ions
✔✔spectator ions - ✔✔ions not included in the reaction
✔✔neutralization RXN - ✔✔Acid+Base----> salt water
, ✔✔Monoprotic acid - ✔✔donates 1 hydrogen
✔✔diprotic acid - ✔✔donates 2 hydrogen
✔✔triprotic - ✔✔donates 3 hydrogens
✔✔Acid properties - ✔✔proton donors
tastes sour
corrosive
✔✔base properties - ✔✔proton acceptors
tastes bitter
caustic
✔✔Oxidation - reduction Reactions - ✔✔swapping electrons
✔✔OILRIG - ✔✔O-xidation
I-s
L-oss
R-eduction
I-s
G-ain
✔✔exothermic reaction - ✔✔A+B----> C+Heat (-) Heat:-#
✔✔endothermic reaction - ✔✔Heat+A+B----> C (+) Heat:+#
✔✔Energy - ✔✔capacity to do work
✔✔1 Calorie - ✔✔=4.184 J
✔✔System - ✔✔chemical RXN/Product/Solvent
✔✔Surrounding - ✔✔everything else
✔✔degrees C to Degrees K - ✔✔K=C+273.15
✔✔Hess's Law - ✔✔a) flipping a rxn changes the sign of Change H
b) multiplying by a coefficient means multiplying Change H by the same coefficient
c) add all changeH's at the end
✔✔Standard Heat of Formation - ✔✔elements in natural form
ΣHproducts - ΣHreactants
