All AP Chemistry Resources
Example Questions
Example Question #5 :Precipitates And Calculations
A chemist has 5.2L of a 0.3Msolution. If the solvent were boiled off, what would be the mass of the remaining solid?
First we will figure out the number of moles ofthat we have. We have 5.2 L of a 0.3 M solution, so:
Now the problem is to find the mass of 1.56 moles of. First, we need to know the molecular weight of. We will go to the periodic table and add up the mass of each element present.
Now the problem is simple as we have the molar mass and the number of desired moles.
Example Question #31 :年代olutions
Given a pKaof 6.37 for the first deprotonation of carbonic acid (), what is the ratio of bicarbonate () to carbonic acid () at pH 5.60?
Assume that the effect of the deprotonation of bicarbonate is negligible in your calculations.
Use the Henderson-Hasselbalch equation to determine the ratio of bicarbonate to carbonic acid in solution:
年代olve for the ratio we need to answer the question:
Example Question #7 :Precipitates And Calculations
Theof(at 298K) is. What is the molar solubility of the hydroxide ion () in a saturated solution of?
The dissociation of calcium hydroxide in aqueous solution is:
Theof calcium hydroxide is related to the dissolved concentrations of its counterions:
andare produced in a molar ratio of 1:2; for each molecule of calcium hydroxide that dissolves:
Given avalue of, the molar solubilities of each counterion may be determined by setting. It follows that:
Now, we can use basic algebra to solve for:
年代ince we set, and, multiplying the value ofby two gives the correct answer, which is 0.022M.
Example Question #1 :Precipitates And Calculations
What type of reaction is also known as a precipitation reaction?
Double replacement
Combustion
Decomposition
Combination
年代ingle replacement
Double replacement
可以进一步目前双置换反应rized as precipitation reactions since it is possible to make a precipitate (solid) from mixing two liquids. Combustion reactions involve using oxygen to burn another species, and the products are carbon dioxide and water. Combination reactions involve the synthesis of one molecule from two separate ones; decomposition is the opposite.
Example Question #1 :年代olubility And Equilibrium
Calculate the molar solubility of AgBr in 0.050 M AgNO3at room temperature. The Kspof AgBr is 5.4 x 10-13.
1.57 x 10-12M
2.16 M
1.08 M
1.08 x 10-11M
2.16 x 10-11M
1.08 x 10-11M
Example Question #2 :年代olubility And Equilibrium
Would the molar solubility of Cr(OH)3increase or decrease as the pH is lowered (i.e. made more acidic)?
Can not be determined
Increase
There is no change
Decrease
Increase
年代ince Cr(OH)3is a basic salt, decreasing the pH makes it more soluble.
Example Question #2 :年代olubility And Equilibrium
Calculate the molar solubility of SrF2in 0.023M NaF. The Kspfor SrF2is 4.3 x 10-9.
5.2 x 10-4M
3.2 x 10-3M
1.6 x 10-3M
8.1 x 10-6M
3.2 x 10-5M
8.1 x 10-6M
Example Question #81 :年代olutions And States Of Matter
Calculate the molar solubility of Mn(OH)2at pH 9.5. The Kspfor Mn(OH)2is 1.6 x 10-13.
3.5 x 10-4M
1.6 x 10-4M
1.5 x 10-3M
2.4 x 10-3M
2.1 x 10-5M
1.6 x 10-4M
Example Question #82 :年代olutions And States Of Matter
计算摩尔CaF的溶解度2(Ksp= 3.9 x 10-11) in a room temperature solution of 0.010 M Ca(C2H3O2)2.
3.1 x 10-5M
1.6 x 10-2M
3.2 x 10-2M
4.2 x 10-4M
3.7 x 10-4M
3.1 x 10-5M
Example Question #1 :Other Solution Concepts
A solution on NaCl has a denisty of 1.075 g/mL. If there are 0.475 L of solution present, what is the mass?
1.075 g /mL* 0.475L
First, convert to mL
1.075 g /mL*475 mL= 510.6 g
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