Miscellaneous
how many molecules are in a mol?
6.022 x 1023
Convert 2.15 mols of Ca(ClO2)2 to grams
376 g Ca(ClO2)2
What is the molarity of a 1.5 L solution containing 2.6 mols of CaCl2?
1.7 M CaCl2
Oxygen has an oxidation state of -2 except when it is bonded with what element?
Fluorine (F)
Balance the following equation:
__Na + __Cl2 --> __NaCl
2Na + Cl2 --> 2NaCl
What is the empirical formula of Glucose (C6H12O6)?
CH2O
How many grams of CO2 are produced when 3.50 moles of propane (C3H8) react completely with oxygen? the balanced equation is below:
C3H8 + 5O2 --> 3CO2 + 4H2O
462 g CO2
Calculate the mass of NaCl in 75.0 ml of a 0.525 M solution.
2.30g NaCl
What is the oxidation state of each element in SF6?
S: +6
F: -1
Balance the following reaction:
__Pb(NO3)4 + __Na --> __NaNO3 + __ Pb
Pb(NO3)4 + 4Na --> 4NaNO3 + Pb
What is the mass % of each element in H2Cr2O7? Round each to 3 sig figs.
H: 0.925%
Cr: 47.7%
O: 51.4%
50.0 g of F2 gas is reacted with an excess of sodium. Given the following unbalanced equation, what is the mass of NaF produced?
Na + F2 --> NaF
111 g NaF
A 50.0 ml solution of 2.75M NaCl is diluted to 200. ml. What is the final concentration?
[NaCl] = 0.688 M
Find the oxidation states of all elements in the following three compounds:
1. ClO-
2. ClO2-
3. ClO3-
1. Cl = +1, O = -2
2. Cl = +3, O = -2
3. Cl = +5, O = -2
Balance:
__Al + __HCl --> __AlCl3 + __H2
2Al + 6HCl --> 2AlCl3 + 3H2
Complete and balance the following acid-base reaction:
H3PO4 + Ca(OH)2 -->
2H3PO4 + 3Ca(OH)2 --> Ca3(PO4)2 + 6H2O
In the following reaction, 165 ml of 2.50M Fe(NO3)2 is added to a solution of excess NaOH to precipitate Fe(OH)2. The unbalanced reaction is displayed below:
__Fe(NO3)2(aq) + __NaOH(aq) --> __NaNO3(aq) + __Fe(OH)2(s)
What is the mass of Fe(OH2) produced?
Bonus 100 points: List the spectator ions
37.1 g Fe(OH2)
Spectator ions: Na+, NO3-
DAILY DOUBLE!
15.0 ml of a 1.00 M solution of NaCN is diluted to 100. ml. A 20.0 ml aliquot of this new solution is further diluted to 100. ml. What is the final concentration?
0.0300 M NaCN
Label the following as reduced or oxidized (for #3, just look at Ag):
1. Fe3+ --> Fe+
2. Cl- --> Cl
3. Ag --> AgCl
1. Reduced
2. Oxidized
3. Oxidized
Balance the following chemical reaction:
__NaNO3 --> __Na3N + __O2 + __N2
6NaNO3 --> 2Na3N + 9O2 + 2N2
Balance, write the total ionic equation, net ionic equation, and list the spectator ions for the following reaction:
NaOH(aq) + MgCl2(aq) --> NaCl(aq) + Mg(OH)2(s)
Balanced equation: 2NaOH(aq) + MgCl2(aq) --> 2NaCl(aq) + Mg(OH)2(s)
Total ionic: 2Na+(aq) + 2OH-(aq) + Mg2+(aq) + 2Cl-(aq) --> 2Na+(aq) + 2Cl-(aq) + Mg(OH)2(s)
Net ionic: 2OH-(aq) + Mg2+(aq) --> Mg(OH)2(s)
Spectator ions: Na+, Cl-
80 g of NaOH reacts with 120.0 g of H2SO4. The unbalanced equation is shown below:
__NaOH + __H2SO4 --> __Na2SO4 + __H2O
1. How many grams of Na2SO4 should theoretically be produced? 2. What is the limiting reactant? 3. If 115 g of Na2SO4 are recovered, what is the % yield?
142g Na2SO4
Limiting reactant: H2SO4
% yield: 81.0%
85.0 ml of an 18.0 M solution of HNO3 is combined with 115 ml of a 2.50M solution of HNO3. What is the final concentration of this new solution?
9.10 M HNO3
Identify the oxidation number of each element in the reaction, then use arrows to indicate which atom is being oxidized and reduced.
2Fe + 3H2O --> Fe2O3 + 3H2
Reactant oxidation states: Fe = 0, H = +1, O = -2
Product oxidation states: Fe = +3, H = 0, O = -2
Reduced: H, oxidized: Fe
Balance the following combustion reaction:
__C125H202O24 + __O2 --> __CO2 + __H2O
2C125H202O24 + 327O2 --> 250CO2 + 202H2O