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Example Questions
Example Question #1 : Solutions And Mixtures
What is the molarity of a solution that contains
of potassium nitrate?
In order to solve for molarity, we need to know the necessary equation to use. Molarity is given by the moles of solute divided by the liters of solution.
Since we are given the mass of potassium nitrate, we must first convert it into moles before we can solve for the molarity of the solution. Potassium nitrate has the formula . Use this to calculate the molar mass.
Now that we have the number of moles, we can solve for the molarity of the solution using the given volume:
Example Question #1 : Solutions And Mixtures
Which of the following is an example of a mixture?
A nutrient mix for plants contains dissolved nitrogen, phosphorus, and potassium
A sugar cube dissolved in a cup of coffee
Yeast in the bottom of a bottle of wine
A glass of warm salt water
Yeast in the bottom of a bottle of wine
A mixture can be filtered or otherwise separated into its individual components. In this case, we could filter out the solid yeast from the bottom of the bottle of liquid wine. However, we could not filter out the salt, sugar, or nutrients since they are chemically mixed into the water, are in the same phase. The the salt water, coffee, and nutrient water are incorrect since these are solutions.
Example Question #1 : Solutions And Mixtures
Which of the following is an example of a solution?
Rice cooking in a pot of water
A chef making a salad out of spinach, walnuts, gorgonzola cheese, and apples
A farmhand combining solid fertilizers in a bin
Lemonade made from dissolving concentrate in water
Lemonade made from dissolving concentrate in water
To identify a solution, look for a homogenous mixture composed of only one phase. Thre rice, salad, and fertilizer are descriptions of mixtures: combinations of materials which can be physically separated. The only option describing a solution is the lemonade solution since the concentrate is dissolved in water, which results in a homogenous mixture. Solutions are both mechanically and chemically combined.
Example Question #2 : Solutions And Mixtures
Which is considered the solute when hydrochloric acid is used to disolve sodium bisulfite?
Sodium bisulfite
Two or more of these are correct
Hydrochloric acid
None of these is correct
Sodium bisulfite
The solvent can be thought of as the substance present in greater amount, or the substance in which the solute is dissolved. Solvents are often liquid. The solute is the substance present in lesser amounts, and is dissolved by the solvent. In this case, the hydrochloric acid is the solvent, because it dissolves the sodium bisulfite. Because it is getting dissolved, the sodium bisulfite is the solute.
Example Question #1 : Identifying Mixtures And Solutions
Which phase label subscript is associated with a soluble compound?
(r)
(l)
(s)
(g)
(aq)
(aq)
If something is soluble, it means it's dissolved in liquid. Generally, the compound associate with the liquid (l) phase label is water; everything else takes the (aq) phase. Note that all these phase labels are written as superscripts after the species they are labeling.
All High School Chemistry Resources
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