Phase Diagrams
What two things determine the state of an element or compound?
Temperature and Pressure
Define % yield, either in words or equation.
The actual yield divided by the theoretical yield multiplied by 100.
2KClO3 + 2KCl --> 3O2
How many moles of O2 form if 3.0 mol of KClO3 are totally consumed?
4.5 mol
500 mol CO and 750 mol H2 are present for the following chemical reaction:
CO + 2H2 --> CH3OH
What is the limiting reactant?
(You have 10 seconds to answer this question to receive points)
H2
Name 1 things that can impact % yield.
1. a side reaction that competes with the main reaction.
2. a reverse reaction that causes products to reform reactants
3. human error (measurements, procedure, etc)
4. impurities in the reactants that impact the reaction
Using the following phase diagram, what state(s) exist at 0.01 degrees C and 0.06 atm?
Solid, liquid and gas.
Define mole ratio.
A mole ratio is a conversion factor that relates the amounts in moles of any two substances involved in a chemical reaction.
Given the following equation:
H2+F2--> 2HF
How many grams of HF are produced as 5 mol of Florine react?
200 g
2As2O3 + 3C--> 3CO2 + 4As
If 6.0 mol of each reactant are available for the above reaction, the mixture remaining after the reaction should contain:
a. 4.0 mol As
b. 4.0 mol CO2
c. 6.0 mol CO2
d. equal quantities of the products
c. 6.0 mol CO2
The actual yield of a reacton is 22g and the theoretical yield is 25g. Calculate the percentage yield.
88%
Using the following phase diagram, what state will water change to and from if the temperature is changed from 100 degrees to 0 degrees and the pressure remains at 0.06 atm?
Changes from gas to solid.
What is the difference between theoretical yield vs actual yield? Do they refer to the reactants, products or both?
They only refer to the products.
Theoretical yield is what is expected to be produced from the stoichimetry equations.
Actual yield is what is determined to be produced through experimentation for a given set of conditions.
What mass of oxygen gas is produced if 100 g of lithium perchlorate are heated and allowed to decompose according to the following equation:
LiClO4 --> LiCl + 2O2
60 g
6.0 mol of N2 are mixes with 12.0 mol of H2 according to the following equation:
N2+3H2 --> 2NH3.
Which chemical is in excess and what is the excess in moles?
N2 and 2.0 mol.
6.0 mol of N2 are mixes with 12.0 mol of H2 according to the following equation:
N2+3H2 --> 2NH3
If the percent yield is 80%, how many moles of NH3 are actually produced?
6 mol
Using the following phase diagram, what state will water change to and from if the temperature is 50 degrees and the pressure changes from 1 atm to 0.01 atm?
It will change from water to steam.
Define limiting reactant.
The limiting reactant (or limiting reagent) is the reactant that gets consumed first in a chemical reaction and therefore limits how much product can be formed. (khan academy)
Sodium metal reacts with water to produce sodium hydroxide and hydrogen gas.
How many grams of NaOH are produced if 20.0 g of sodium metal reacts with excess water?
The balanced equation is:
2Na+2H2O --> 2NaOH + H2
34.8g of NaOH are produced.
Aspirin, C9H8O4, is synthesized by the reaction of salicylic acid, C7H6O3, with acetic anhydride, C4H6O3.
C7H6O3 + C4H6O3 --> C9H8O4 + CH3COOH
If 20.0 g of C7H6O3 and C4H6O3 are present, what mass of aspirin can be produced?
26.1g
Huge quantities of sulfur dioxide are produced from zinc sulfide by means of the following reaction:
2ZnS + 3O2 --> 2ZnO + 2SO2
If the typical yield is 86.78%, what mass off= SO2 should be expected if 4897g of ZnS are used?
2794 g SO2
Draw a general phase diagram. It must include the following labels:
temperature
pressure
solid
liquid
gas
triple point
critical point
Temperature on x axis
Pressure on y axis
one line going to the triple point, two lines coming out of the triple point. The critical point should be at the end of the line dividing liquid and vapor.
Define triple point.
Triple point on a phase diagram is indicated by the point where all three equilibrium lines meet. This is the temperature and pressure combination that allows for all three phases of a substance to occur simultaneously. There will be solid, liquid and gas molecules all existing in a state of equilibrium. (study.com)
A car airbag requires 70L of nitrogen gas to inflate properly. The following equation represents the production of nitrogen gas:
2NaN3 --> 2Na + 3N2
The density of nitrogen gas is typically 1.16 g/L at room temperature. Calculate the number of grams of NaN3 that must be used to generate the amount of N2 necessary to properly inflate the airbag.
First determine that 80g of N2 are needed to produce a volume of 70L.
Then you can use stoichiometry to convert to 100g of NaN3
Sulfuric acid, H2SO4, reacts with aluminum hydroxide by double replacement, with one of the products being water. If 30.0g of sulfuric acid react with 25.0g of aluminum hydroxide, determine the mass of each product formed assuming 100% yield.
Balanced equation:
3H2SO4 + 2Al(OH)3 --> Al2(SO4)3 + 6H2O
34.9g Al2(SO4)3
11.0 g H2O
Coal gasification is a process that converts coal into methane gas based on the following equation:
2C + 2H2O --> CH4 + CO2
If the percent yield is increased from 85.0% to 95.0%, how much more methane, in moles, can be obtained if have have 1250 g of C and 3001 g H2O?
8.34 or 8.33 more moles of CH4
(depending on rounding)