## Sundry Items:

Brainbashers Daily Logic Puzzle

Brain Den's Best Puzzles

Sporcle: mentally stimulating diversions

Canadian, please funny, patriotic video

Swiss army knife was invented 12/June/1897.

(I have a couple, including a Champion for tripping and general cottage work).

Brain Den's Best Puzzles

Sporcle: mentally stimulating diversions

Canadian, please funny, patriotic video

Swiss army knife was invented 12/June/1897.

(I have a couple, including a Champion for tripping and general cottage work).

More importantly 41% (122/300) of questions answered (mostly Chemistry and Math) were voted Best Answer - mainly through providing a detailed explanation.

Here's an example:

Great question and a very valuable skill.

Basically you make sure that all the dimensions are in the correct order so things can be crossed out and you get the correct answer with the correct units.

- Often it involves multiplying things by what is in fact 1 like 1 L/ 1000 ml or 1 inch/ 2.54 cm (Ex 1 and 2)

- Other times it involves formulas and constants. (Ex 3)

You can even figure out formula's that you might have forgotten by looking at all the dimensions.

Examples:

1) Convert 6 feet to cms:

6 feet * 12 inch/ 1 foot (=1) * 2.54 cm/ inch (=1) = 183 feet/foot inch/inch cm = 183 cm

2) Covert 15 years old to seconds

15 years old * 365.24 days/ 1 year (=1) * 24 hours/ 1 day (=1) * 60 min/ 1 hour (=1) * 60 sec/ 1 min (=1)

= 15 * 365.24*24*60*60 years/year days/day hours/hour min/min sec old = 473,358,816 sec old

3a) The Ideal gas law is PV=nRT where R = 8.314 L kPa K−1 mol−1

so if you are given P(ressure) = 101 kPa, n (moles) =1/18 and T(emperature) = 596 K

you can calculate the volume as follows:

101 kPa * V = 1/18 mol * 8.314 L kPa K−1 mol−1 *596 K

rearranging

V= 1/18*8.314*596/101 mol*mol-1 kPa/kPa K*K-1 L = 2.7 L

3b) If the Pressure was given as 101,000 Pa then 101,000 Pa * 1 kilounit/ 1000 units (=1) = 101 kPa

3c) If the Temperature was given as 323 oC then T (K) = 273 + T(oC) so T (K)= 273 +323oC = 596 K

3d) if they want the answer in m3 then 2.7 L * 1 m3/1000 L (=1) = 0.0027 m3

Good Luck and keep practicing as this is invaluable.

Source(s): http://www.chem.tamu.edu/class/fyp/mathrex/mr-da.html

Here's an example:

**Describe how Dimensional Analysis works?****Best Answer**- Chosen by VotersGreat question and a very valuable skill.

Basically you make sure that all the dimensions are in the correct order so things can be crossed out and you get the correct answer with the correct units.

- Often it involves multiplying things by what is in fact 1 like 1 L/ 1000 ml or 1 inch/ 2.54 cm (Ex 1 and 2)

- Other times it involves formulas and constants. (Ex 3)

You can even figure out formula's that you might have forgotten by looking at all the dimensions.

Examples:

1) Convert 6 feet to cms:

6 feet * 12 inch/ 1 foot (=1) * 2.54 cm/ inch (=1) = 183 feet/foot inch/inch cm = 183 cm

2) Covert 15 years old to seconds

15 years old * 365.24 days/ 1 year (=1) * 24 hours/ 1 day (=1) * 60 min/ 1 hour (=1) * 60 sec/ 1 min (=1)

= 15 * 365.24*24*60*60 years/year days/day hours/hour min/min sec old = 473,358,816 sec old

3a) The Ideal gas law is PV=nRT where R = 8.314 L kPa K−1 mol−1

so if you are given P(ressure) = 101 kPa, n (moles) =1/18 and T(emperature) = 596 K

you can calculate the volume as follows:

101 kPa * V = 1/18 mol * 8.314 L kPa K−1 mol−1 *596 K

rearranging

V= 1/18*8.314*596/101 mol*mol-1 kPa/kPa K*K-1 L = 2.7 L

3b) If the Pressure was given as 101,000 Pa then 101,000 Pa * 1 kilounit/ 1000 units (=1) = 101 kPa

3c) If the Temperature was given as 323 oC then T (K) = 273 + T(oC) so T (K)= 273 +323oC = 596 K

3d) if they want the answer in m3 then 2.7 L * 1 m3/1000 L (=1) = 0.0027 m3

Good Luck and keep practicing as this is invaluable.

Source(s): http://www.chem.tamu.edu/class/fyp/mathrex/mr-da.html