Unit 1: Chemical Reactions
True or False? The following chemical equation follows the law of conservation of mass.
NH3 --> N2 + H2
False, the equation is unbalanced.
Is a substance with a pH of 12 an acid, base or neutral?
Base
What are the three phases of matter?
Solid, liquid, gas
Convert 70 Kelvin to Celcius given
K − 273.15 = C
- 203.15 degrees Celcius
Which phase of matter has the least amount of kinetic energy and the STRONGEST force of attraction- holding its atoms tightly together?
solids
List three physical pieces of evidence that suggest a chemical reaction has occurred?
Change in color,
Production of heat, gas, or light,
Formation of a precipitate
Change in odor.
What happens to the number of H+ after H2SO4 is added to water?
The number of H+ ions increases
Is melting an endothermic or exothermic process?
Melting is an endothermic process (it takes energy going into the system to melt a substance).
Given the following conversion factors
1 atm = 101.3 kPa = 101,325 Pa = 760 mm Hg = 760 torr
Convert 202.6 kpa into atm
202.6 kPa = 2.0 atm
Which phase of matter has the has a fixed volume but no fixed shape?
Liquids
Is the forward reaction below an endothermic or exothermic reaction?
N2(g) + 3 H2(g) <--> 2 NH3(g) + 92 kJ
Exothermic Reaction
What are the products generated from the neutralization reaction between HCl and NaOH?
H2O and NaCl
What is it called when a substance goes from a solid to a gas?
Sublimation
If the volume of a gas is cut in half while keeping the temperature constant, what happens to its pressure?
The pressure doubles.
Does adding more reactant speed up or slow down the rate of a chemical reaction?
Speed up
Balance the following chemical reaction:
___SF4 + ___ H2O → ___ SO2 + ___ HF
1 SF4 + 2 H2O → 1 SO2 + 4 HF
What acid and base would be used to generate the salt Zn(NO3)2
HNO3 and Zn(OH)2
At what point in a heating curve does the temperature remain constant while heat is being added?
During a phase change
Mrs. Haan's body contains 24.3 grams of magnesium. Use the mole conversion chart and your periodic table to determine, how many atoms of magnesium are in her body?
6.022 x 1023 atoms of Magnesium
Why does increasing the temperature increase the rate of chemical reactions? Use collision theory.
More kinetic energy causes molecules to collide more frequently.
Classify each chemical reaction below by reaction type:
Reaction 1. Al2(SO4)3 + BaCl2 → BaSO4 + AlCl3
Reaction 2. Cl2 + KBr → KCl + Br2
Reaction 3. C4H12 + O2 → H2O + CO2 + heat
Reaction 4. Zn + S → ZnS
Reaction 5. NH4NO3 → N2O + H2O
Reaction 6. 2HBr + Mg(OH)2 → MgBr2 + 2 H2O
Reaction 1. Double Displacement
Reaction 2. Single Displacement
Reaction 3. Combustion
Reaction 4. Synthesis
Reaction 5. Decomposition
Reaction 6. Acid Base Reaction
Pure water (H2O) is considered neutral and has a pH of 7. Why?
Water dissociates into an equal number of hydrogen ions (H⁺) and hydroxide ions (OH⁻) creating a neutral pH of 7.
Each of two or more different physical forms in which an element can exist. Graphite, charcoal, and diamond are all allotropes of carbon.
How many moles of gas does it take to occupy 100 liters at a pressure of 3 atmospheres and a temperature of 300 K?
Use the equation PV=nRT and round to the nearest tenth (first decimal).
R = 0.08206 L.atm/mol.K
12.2 mol
Balance the following:
____ Ba(OH)2 + ____ Fe2(SO4)3 → ____ BaSO4 + ____ Fe(OH)3
3 Ba(OH)2 + 1 Fe2(SO4)3 → 3 BaSO4 + 2 Fe(OH)3