DavidQD

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 #3
avatar+330 
+11

 

how many grams are in 5.0*10^26 molecules of Cl2

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(Greetings Alan, It is diatomic Chlorine, not carbon).

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This question originally had an anonymously appended, incorrect answer to the chemistry question, and a vulgar-worded (probably why it was deleted) opinion stating this is a math site and not a chemistry site. My comments below reflect this.

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The chemistry answer by Anonymous is incorrect. 

The correct solution and the method for its derivation are below.

His/her opinion of the site is subjective. There are tutors on this site who know chemistry. Any science question, which relates to applied mathematics is reasonable.

To solve this:

Divide the quantity of the molecules by Avogadro constant (currently: 6.022141E23/mol). This constant is the number of atoms or molecules per molar mass of an element or compound.

5.0*10E26 molecules (Cl2)/ 6.022141E23/mol = 830.3 mols of Cl2

Look up the Relative atomic mass (aka Standard atomic weight) of Cl (Chlorine). It is 35.45. Pure Chlorine, in the gas state, usually exists in a diatomic form (Cl2). This condition is indicated by the subscript. Multiply the Relative atomic mass by this subscript value (2): 35.45 *2 = 70.90. (Note that diatomic forms are considered molecules).

The Relative atomic mass of diatomic Chlorine is 70.90. Convert to gram mass (by multiplying by 1g). 70.90 * 1g = 70.90g. This is the gram molecular mass and it equals 1 mol: 70.90g of Cl2 = 1 mol. Restated: for each mol of Cl2 there are 70.90 grams of Cl2.*

Multiply the 830.3 mols of Cl2 by 70.90g/mol = 58873.2g of Cl2. (58.8732Kg of Cl2).

This is slightly less chlorine than required to maintain "chemical pasteurization” of an Olympic-size non-comercial pool.

 ~~D~~

May 2, 2014
 #6
avatar+330 
+8

 

http://en.wikipedia.org/wiki/Radian

...

The radian is represented by the symbol rad (Unicode-encoded as U+33AD ㎭ ). An alternative symbol is the superscript letter c, for "circular measure"—but this is infrequently used as it can be easily mistaken for a degree symbol (°). So for example, a value of 1.2 radians could be written as 1.2 rad, 1.2rad, or 1.2c.

...

Quote Alan: I'm much more used to assuming that radians are meant unless the degree symbol is used. ...

Engineers are used to Radians.

Side note: Most calculators are 10 times more precise (including this site) when trig functions are preformed in degrees instead of radians. If you need high precision, converting as needed is an optimal decision.

~~D~~

Apr 29, 2014
 #5
avatar+330 
+8

The following site lists countries by their number format system

www.codeproject.com/Articles/78175/International-Number-Formats

(The list is recent and comprehensive)

These formats are the most common

1,234.56

1.234,56

1'234.56

1 234,56

These formats are rare, used by one or two countries.

1,234/56

1 234-56

1 234.56

 

---- Note: Some multicultural countries use more than one format. It is probable that cross-cultural communications are sent in the recipient’s format, for clarity. Computer communications may automatically convert to recipient’s format via computer settings. ~~D~~

Apr 27, 2014
 #3
avatar+330 
+8

yeah it is $100 000 000 000 but what is up with all the decimal points in Anonymous' anwer by bioschip

****

Some cultures interchange the use of commas (,) and decimals (.)

100.000.000.000 = 100,000,000,000

0,02580 = 0.02580

The calculator on this site uses either convention depending on context. Entering the above or similar formatted numbers will yield correct results.

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Note also, with the use of two specifically spaced commas the calculator will display results in scientific notation.

For example: enter 2^199 and the calculator will display 60 decimal digits; choose an arbitrary position to the right of the first digit and enter a comma, move three more to the right and enter another comma, then click the “=” (or press enter). The display will convert to (standard) scientific notation, with up to a 16-digit mantissa following the decimal point and its preceding value. (In this example, the value is 8.0346902212949514e59)

The same applies to extremely small values. For example (2^199 )^-1. In this case, choose an arbitrary place to the right of the first value after the decimal point, and place the second coma three values to the right. (In this example, the value is 1.245e-60).

The short version is: two comas, three values apart. The above also works with negative numbers.

This computer generated “calculator” is a brilliant peace of programming. At one time, this calculator would generate results with atomic accuracy at galactic distances (plus or minus the bugs and limitations of log and trig functions). Now, most functions (except for exponential) are rounded to 16 digits. This is more like galactic accuracy at atomic distances, but it keeps the FLOP load down when tens of thousands of users are seeking solutions.

Another feature of this calculator are “Easter eggs” hidden in the subs. Entering certain string combinations would generate German phrases. There were at least three, but none of them work anymore. The best were, “Speichern Sie diese Scheiße für die Vögel,” and “Führen Sie Sie gefickt bis, ja wissen.”

Here is a brilliant peace of programming and a great sense of humor.

~~D~~

Apr 26, 2014