Stoichiometry/Dimensional Analysis
What's the main purpose of utilizing Dimensional Analysis?
What defines Sig Figs when Adding/Subtracting values?
What defines Sig Figs when Multiplying/Dividing values?
Adding/Subtracting:
# of Decimal Places
Multiplying/Dividing:
# of non-zero Digits + zero Digits after nonzero #'s & D.P.
PbSO4 (s) + HCl (aq) -> H2SO4 (aq) + PbCl2 (s)
This equation is unbalanced. What values need to be changed to balance it?
There need to be TWO HCl molecules per reaction.
PbSO4 (s) + 2 HCl (aq) -> H2SO4 (aq) + PbCl2 (s)
Ionic compound naming: What comes first, Cation or Anion?
Bonus:
What's the major differences between Cations and Anions?
Cation-Anion (CAT-AN)
Cations are :
Positively Charged
Often Metal
Anions are :
Negatively Charged
Often Nonmetal
HNO3 (aq) + NaCl (aq) -> HCl (aq) + NaNO3 (aq)
If 0.050 mol of Nitric Acid and 0.050 mol of Sodium Chloride reacted, how many moles of Hydrochloric Acid would be produced?
0.050 mol HCl
(0.050 mol HNO3 * [1 mol HCl / 1 mol HNO3])
What is the correct rounded answer to this equation?
2FeCl3 (aq) + H₂S (g)-> 2FeCl₂ (aq) + 2HCl (aq) + S (s)
0.0422 M FeCl3 * [1.2 L] * [1 mol S / 2 mol FeCl2] * [32.07 g S / 1 mol S] = 0.8120124 g FeCl3
0.81 g FeCl3
What is the proper net ionic equation for this unbalanced equation?
Al (s) + AgNO3 (aq) → Al(NO3)3 (aq) + Ag (s)
Al (s) + 3 AgNO3 (aq) → Al(NO3)3 (aq) + 3 Ag (s)
Al (s) + 3 Ag (aq) + 3 NO3 (aq) → Al (aq) + 3 NO3 (aq) + 3 Ag (s)
Al (s) + 3 Ag (aq) + → Al (aq) + 3 Ag (s)
When do you add a prefix to the first element in a molecular formula?
Bonus:
What are the first four greek prefixes used in molecular naming?
When there are more than one atoms of that element present.
Mono-
Di-
Tri-
Tetra-
PbSO4 (s) + 2 HCl (aq) -> H2SO4 (aq) + PbCl2 (s)
What steps would you take to convert from Grams HCl to Molarity H2SO4?
g HCL * [1 mol HCl / 36.46 g HCl] * [1 mol H2SO4 / 2 mol HCl] * [1/L]
How many Sig Figs should this Percent Error Calculation have?
( |18.2g - 17.8g| / 17.8g ) * 100% = 2.24719%
One, 2%
How do you find the ΔH of the following reaction, when given Heat of Formation Values:
2 A (g) + 3 B (g) → 2 C (g) + 2 D (g)
[(2 mol C * ∆Hf° C) + (2 mol D * ∆Hf° B)] - [(2 mol A * ∆Hf° A) + (3 mol B * ∆Hf° B)]
What are the Three Naming Conventions for Acids? (What types acids have what suffixes?)
Bonus:What differentiates acids and ionic compounds?
Single-atom Acids:
hydro-___-ic acid
-ate anions:
___-ic acid
-ite anions:
___-ous acid
Acids:
- Hydrogen as Cation
- Always water soluble
- Some weakly dissociative, some strongly dissociative
Ionic:
- Metal as Cation
- Sometimes water soluble
- When soluble, always strongly dissociative
How would you find the heat released for a specified mass (in grams) of Oxygen reacted?
4 NH3 (g) + 5 O2 (g) → 4 NO (g) + 6 H2O (g)
∆H = ‒906 kJ
g O2 * [1 mol O2 / 32.00 g O2] * [906 kJ / 5 mol O2 = kJ (generated)
What defines Sig Figs through Logarithmic and Anti-Logarithmic [Exponential] functions?
Logarithmic:
Sig Figs put in -> D.P. in Result
Anti-Log:
D.P. put in -> Sig Figs in Result
How would you find the enthalpy of the combined equation given two similar equations?
2 A (g) + 3 B (g) → 2 C (g) + 2 D (g) ∆H = ?
A (g) → D(g) + E (g) ∆H = +200
2 D (g) + 2 C (g) → 3 B (g) + 2 E (g) ∆H = - 150
2 A (g) → 2 D(g) + 2 E (g) ∆H = 2[+200]
3 B (g) + 2 E (g) → 2 D (g) + 2 C (g) ∆H = -[-150]
2 A (g) + 3 B (g) → 2 C (g) + 2 D (g) ∆H = +550
DAILY DOUBLE!!!
What is the name of the following molecular geometry?
Trigonal Pyramidal