Solutions and Titrations (Neutralization)
What is a strong electrolyte defined as?
A solute that is present in solution only/mostly as ions, or one that dissociates completely. (e.g. NaCl in water)
What is the concentration, in M, of NaCl in an aqueous solution of 6.32g NaCl in 362mL of DI water?
0.299M NaCl
Cr2O72-
+6
How much volume does one mole of gas occupy at STP?
What is the general equation given by Dalton's Law?
Ptotal = P1 + P2 + P3...
What is a weak electrolyte defined as?
A solute that only partially dissociates or ionizes in solution. (e.g. AgCl; some will exist as Ag+ and Cl- in water, but most will be solid AgCl)
How many moles of LiBr are in 50.0mL of a 1.25M LiBr solution?
0.0625 moles LiBr
What is the oxidation number of sulfur in the following compound?
Na2SO4
+6
If an ideal gas is trapped in a flexible container at 5.0atm and occupies 1.5L, what volume will it occupy at 1.0atm?
7.5L
What equation relates the mole fraction of a particular gas with the pressure of that gas and the total pressure of all gases in a container?
Pgas = X*Ptotal
Where X is the mole fraction. In other words:
X = Pgas/Ptotal
This is also used for moles of the gases (alternatively to pressure).
What is a non-electrolyte defined as?
A solute that only exists in solution as complete molecules; does NOT dissociate. (e.g. glucose (sugar) or ethanol - they dissolve in water but do not dissociate)
What is the molarity of sodium ion in a solution of 12.2g sodium phosphate dissolved in 500.0mL of DI water?
0.446M Na+
What is the oxidation state of carbon in the following compound?
CH3F
-2
If the volume of a fixed amount of a gas is tripled at constant temperature, what happens to the pressure?
The pressure decreases by a factor of three. (i.e. multiplied by 1/3)
H2 gas is collected over water at a total pressure of 742mmHg at 296K. Assume the vapor pressure of water at this temperature is 21mmHg. What is the partial pressure of H2 gas collected?
721mmHg
How many moles of hydroxide (OH-) are required to completely neutralize 20.0mL of a solution of 1.0M H2SO4?
0.040 moles OH-
What is the concentration of Na+ in solution if 20.0mL of a 0.446M NaCl solution is diluted to 150.0mL?
0.059M Na+
Which element is reduced in the following reaction?
2Al + Fe2O3 -> 2Fe + Al2O3
Iron (Fe)
What is the new volume of 1.00L of an ideal gas if the temperature rises from 274K to 574K?
2.09L
A container at STP occupies 5.0L and contains 2.5g of CO2. What is the mole fraction of CO2 in the container?
X = 0.255
What volume of 0.200M HNO3 is needed to neutralize 69.7mL of 0.150M Ca(OH)2?
0.105L HNO3
I have 10mL of concentrated HCl (12M). I need to make 1.0L of a 0.020M HCl solution with the concentrated HCl. How much concentrated HCl do I need?
1.7*10-3 L
What element is the oxidizing agent in the following balanced redox reaction?
14H+ + Cr2O72- + 6Fe2+ -> 2Cr3+ + 7H2O + 6Fe3+
Chromium (Cr)
How many grams of gas are present in a 0.100L sample of CO2 at 0.404atm and 299K?
7.24*10-2g CO2
The rate of photosynthesis was determined by measuring O2 produced by an aquatic plant over time. A total pressure of 755.2mmHg at 293K of 1.02L gas were collected over water. What amount of O2, in grams, was formed?
Note: the vapor pressure of H2O at 293K is 17.55mmHg
1.32g O2