## Solutions Molarity & Dilutions Practice Available

- Details
- Written by Mr. Franz

The site has added unlimited practice problems for two categories of solutions, molarity & dilutions. You can calculate the molarity of a solution given grams or moles, or calculated the volume, moles or mass of a substance given two of the variables. Many can me done with just a calculator, but you should download a periodic table (Texas Chemistry STAAR Reference Materials) for the molar masses you will need.

Dilutions calculations are also on-line. They are pretty straight forward. Given the equations M1V1 = M2V2, calculate molarity or volume given the other variables. Right now, all volumes are in liters, so there is no conversion to mL necessary, but that is expected to change in the near future.

Just go to http://practice.franzscience.com/solutions.html.

## Molarity & Dilution Calculations

- Details
- Written by William Franz

The practice site now has a solutions unit. While the lessons are still in production, the practice problem modules are complete. You can now try unlimited practice problems for calculating molarity and for calculating dilutions.

The practice problems can be found by going to the practice site, http://practice.franzscience.com, the choosing "Unit 12-Solutions" from the drop-down menu. Choose the lesson in which you are interested on the right - then push the button on the right for unlimited practice problems. The topics with practice problems currently available are: Calculating Concentration and Calculating Dilutions.

When complete, the solutions unit will include lessons and practice problems covering ten (10) topics, including such things as the special properties of water, solubility, solubility curves, electrolytes, and colligative properties.

If you use it, don't forget to like the page.

## Unlimited Gas-Law Practice Problems Now Available

- Details
- Written by William Franz

There is currently a new page that supports an unlimited number of practice problems for four common gas laws: Boyle's Law, Charles' Law of Volumes, the Gay-Lussac Law (which is more commonly known as Amontons' Law of Pressure-Temperature) and Avogadro's Law. An entire website here at FranzScience is dedicated to lessons and practice in science, particularly chemistry. The website is http://practice.franzscience.com, and it currently has the laws mentioned above as well as unlimited practice in two stoichiometry categories.

More laws are planned. First will be the Combined Gas Law, Dalton's law of partial pressures, and finally the Ideal Gas Law, PV=nRT. All of the laws in the gas law section have both a brief description of the law (and who it is named after, if applicable) and examples of its use, and most notably a page that allows students to try an unlimited number of automatically graded practice problems.

In the stoichiometry section there are 70 different balanced equations. The numbers for grams-to-grams calculations and limiting reactant calculations are generated randomly, so there are virtually an unlimited number of combinations.

In the gas law sections, the individual laws available so far only support one set of units. Pressure is in atmospheres, volume in liters, and temperature in Kelvin. Future versions will support multiple units and require the student to occasionally convert, as would occur in real problems on worksheets, quizzes or exams.

Stay tuned to see as new laws are added. After this unit is over, we will move on to Unit 12 - Solutions and Solubility.

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