Question about Office Equipment & Supplies

It's the atomic mass of an element, namely protons AND neutrons usually denoting an isotope. It is only the protons that define the chemical properties (and hence name) of an element. Examples Uranium 235 (fairly common) and Uranium 238 (rare). Only about 1% of natural Uranium is U-238 - that's why Uranium enrichment plants exist - to extract U-238 for power stations and (unfortunately) weapons.

Posted on May 27, 2014

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Posted on Jan 02, 2017

limiting reactant:

The limiting reagent, or also called the "limiting reactant", is the chemical that determines how far the reaction will go before the chemical in question gets used up, causing the reaction to stop. The chemical of which there are fewer moles than the proportion requires is the limiting reagent.

Limiting reagent formula

There is a much simpler formula which can be used. However, you must first calculate the moles of both of the reagents in the reaction. Once the number of moles have been figured out, just simply fill in this equation (reagent 1 being the first reactant and 2 being the second):

When the answer to the formula is less than zero, reagent 1 is the excess reagent. When the answer is larger than zero, reagent 1 is the limiting reagent. The number shows how much in excess one reagent is from another. If the answer for the formula is zero, both reagents are perfectly balanced. The unit of an answer is in moles.

The limiting reagent, or also called the "limiting reactant", is the chemical that determines how far the reaction will go before the chemical in question gets used up, causing the reaction to stop. The chemical of which there are fewer moles than the proportion requires is the limiting reagent.

Limiting reagent formula

There is a much simpler formula which can be used. However, you must first calculate the moles of both of the reagents in the reaction. Once the number of moles have been figured out, just simply fill in this equation (reagent 1 being the first reactant and 2 being the second):

When the answer to the formula is less than zero, reagent 1 is the excess reagent. When the answer is larger than zero, reagent 1 is the limiting reagent. The number shows how much in excess one reagent is from another. If the answer for the formula is zero, both reagents are perfectly balanced. The unit of an answer is in moles.

Oct 17, 2013 | InnerIntimates Vaginal Renewal Complex...

I used the HP LaserJet IIP driver off the WinXP x64 iso. Worked for the SuperScript 1400 in Win 7 x64.

Jul 22, 2011 | NEC SuperScript 1400 Laser Printer

In earlier version of Microsoft Office (Word 2003), trying to write a subscript or superscript takes quite a time but with the new Word 2007
it's so simple. For those who are writing technical articles face
situation to use these subscripts and superscripts in almost every
article like mathematical formulae or chemical equations.

**What are Subscript and Superscript?** A subscript appears smaller and below the baseline (Ex. H2O or X2) while a superscript appears smaller and above the baseline (Ex. X3)

**How to Subscript and Superscript in Office 2003 and 2007?**

In**Word 2003**, select the characters that you would like to change. Go to **Format** menu and Click **Font**, from the **Font** tab you have to select **subscript** or **superscript**.

In**Word 2007**, select the character that you would
like to change and Click the Superscript or Subscript symbol from the
ribbon under the home tab.In both Word 2003 and Word 2007, you can also use **keyboard Shortcut keys** to make the characters as Subscript or Superscript.

** Superscript: Press CTRL+SHIFT+=**

Subscript: Press CTRL+=

If you work on Windows and Office Applications most of the time then these posts on**Keyboard Shortcuts for Windows and Office** will help you a lot.

In

In

Subscript: Press CTRL+=

If you work on Windows and Office Applications most of the time then these posts on

Mar 19, 2011 | Computers & Internet

This problem is the type often encountered in a first semester chemistry course, whether in high school or college.

It is very easy to solve if you already understand the following concepts, and if you also have had lots of practice applying them!

To solve this problem you must be aware of the**balanced chemical equation**, as follows:

Notice that there is**one** C, **one** O2, and **one** CO2.

*(For convenience in my post, I am writing the subscripts on the same line,)*

"One what?" You might ask. It can be__one__ "**molecule**" for each the O2 and CO2; and __one__ "**atom**" of C. For the method of **stoichiometry** in this problem, we should use **one** "mole." So, there is **one** __mole__ of C, **one** __mole__ of O2, and **one** __mole__ of CO2. In other words, the **PROPORTION** of these reactants (C and O2) and product (CO2), is **one to one to one**, also written **one:one:one** (or 1:1:1).

As I am assuming you know, these numbers are called the "**coefficients**" of the balanced chemical equation.

To calculate the**mass in grams of O2** (the unknown *quantity*), we will need only the moles of O2 and the moles of one other substance from the balanced chemical equation. Since we are given the mass of C, we can use the moles of C.

TO WORK A STOICHIOMETRIC problem using a balanced chemical equation, YOU MUST INCLUDE THE MOLES OF TWO SUBSTANCES from the chemical equation in your calcuation, in this case, moles of C and moles of O2. As you know, you can calculate moles of C from the mass (in grams) of C that was given in this problem. You must calculate the moles of O2 by use of the following math expression:

mol O2 = (MOLE RATIO of O2 to C) x mol C.

(Notice that I have used the official abbreviation of moles, which is "mol".)

I will show you how to calculate the MOLE RATIO a moment.

Once you have caculated the moles of O2, you will have only one more calculation to do to calculate the number of grams of O2. Since I am assuming you already know how to calculate grams from moles, I will skip this step until my closing summary.

The MOLE RATIO can be calculated as follows:** The calculated mole ratio will always equal the ratio of corresponding coefficients.**

Notice that the mole ratio actually represents the ratio of the coefficients that are in the balanced chemical equation, and is written in the same order as are the calculated (calc'd) moles.

Therefore,

So, you can see that the number of moles of O2 = calculated moles of C.

The**moles of C** were calculated as follows:

It is very easy to solve if you already understand the following concepts, and if you also have had lots of practice applying them!

- PROPORTIONS
- THE MOLE
- The LAW OF CONSERVATION
- CHEMICAL EQUATIONS
- BALANCED CHEMICAL EQUATIONS
- STOICHIOMETRIC CALCULATIONS
- SIGNIFICANT FIGURES, PRECISION, & ROUNDING OFF CALCULATED QUANTITIES

To solve this problem you must be aware of the

Notice that there is

"One what?" You might ask. It can be

As I am assuming you know, these numbers are called the "

To calculate the

TO WORK A STOICHIOMETRIC problem using a balanced chemical equation, YOU MUST INCLUDE THE MOLES OF TWO SUBSTANCES from the chemical equation in your calcuation, in this case, moles of C and moles of O2. As you know, you can calculate moles of C from the mass (in grams) of C that was given in this problem. You must calculate the moles of O2 by use of the following math expression:

mol O2 = (MOLE RATIO of O2 to C) x mol C.

(Notice that I have used the official abbreviation of moles, which is "mol".)

I will show you how to calculate the MOLE RATIO a moment.

Once you have caculated the moles of O2, you will have only one more calculation to do to calculate the number of grams of O2. Since I am assuming you already know how to calculate grams from moles, I will skip this step until my closing summary.

The MOLE RATIO can be calculated as follows:

Notice that the mole ratio actually represents the ratio of the coefficients that are in the balanced chemical equation, and is written in the same order as are the calculated (calc'd) moles.

Therefore,

So, you can see that the number of moles of O2 = calculated moles of C.

The

The calculated moles of C = [grams C] / [MW of C] = [188 g C / 12.0 g] = 15.7 mol C

Therefore, there are 15.7 moles of O2, as calculated from use of the math expression (with boxes) shown above.

The wanted GRAMS of O2 are calculated from MW of O2 times its number of moles, as follows:

Grams of O2 = 32.0 g O2 x 15.7 mol O2 = **502 grams O2**.

For your convenience as you make conversions among grams and moles, you may use the following memory aid:

To go from moles to grams, just notice that moles are beside MW, so multiplying them will give grams (moles x MW = grams). If you want to go from grams to moles, notice that grams are over MW, so (grams/MW) = moles. If you should want to calculate MW, you would divide grams by moles, (grams/moles) = MW.

One more tip: When doing calculations, use at least the same number of significant figures (*sig figs*) in the molecular weights (and atomic weights) as is in the given numerical data. That is, since there are three sig figs in 188 grams of C, use 12.0 as the atomic weight of C, and 44.0 as the MW of CO2. You would obtain the same answer using 12 and 44, but as you may know, following this rule would be more important in other problems in which the digit past the decimal is not zero. This allows proper rounding off of the final calculated quantity.

**In Summary**

- Write the chemical equation, and balance it.
- Use MOLES to do the necessary stoichiometric calculations. Convert grams to moles to make this possible.
- Multiply the calculated moles of the given amount of chemical compound (or element) by the COEFFICIENT RATIO of the two compounds involved in the problem.
- Convert moles to grams if grams are asked for by the problem.
- Round off correctly.
- Show the answer quantity, which should always show both numerical value AND unit.

Suggestion: Try out this method to other problems involving a chemical reaction. Good luck!

***

Dec 12, 2010 | Scientific Explorer My First Chemistry Kit

Oct 26, 2010 | Computers & Internet

. 9 3 3 x^ 1 . 5

x^ is marked on the keyboard as an x with a superscript rectangle on the key above the sin key. This function lets you raise a value to any number, including 2 and 3.

x^ is marked on the keyboard as an x with a superscript rectangle on the key above the sin key. This function lets you raise a value to any number, including 2 and 3.

Sep 06, 2010 | Casio FX-115ES Scientific Calculator

You could try use the Windows XP SuperScript 870 driver or you could install the HP LaserJet III printer driver. It should work with your printer, but may have limited functionality.

Feb 08, 2010 | NEC SuperScript 870 Laser Printer

Use the "x-superscript-box" key just below and right of the big circular cursor pad. It's the key between the x^2 and log keys.

Mar 09, 2009 | Casio FX-115ES Scientific Calculator

In a word.... no. The NEC SuperScript 860 is a black and white laser printer. It does not print color.

Jan 23, 2008 | NEC SuperScript 860 Laser Printer

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