1,3-Propanediol can be formulated into a variety of industrial products including composites, adhesives, laminates, coatings, moldings, aliphatic polyesters, copolyesters. It is also a solvent and used as an antifreeze and in wood paint. 1,3-Propanediol is mainly produced by the hydration of acrolein. The molar volume of a gas expresses the volume occupied by 1 mole of that respective gas under certain temperature and pressure conditions. The most common example is the molar volume of a gas at STP (Standard Temperature and Pressure), which is equal to 22.4 L for 1 mole of any ideal gas at a temperature equal to 273.15 K and a pressure equal to 1.00 atm.
The molar ratio will assume a place of central importance in solving stoichiometry problems. The sources for these ratios are the coefficients of a balanced equation. We will look at what a molar ratio is and then a brief word on how to recognize which ratio to use in a problem.
The ChemTeam's favorite sample equation is:
2H2 + O2 ---> 2H2O
I will use it for the first three examples. Little big workshop 1 0 11982 (36131) download free.
Example #1: What is the molar ratio between H2 and O2?
Solution:
The ratio is two-to-one. The 2 is the coefficient in front of the H2 and the 1 is the coefficient understood to be in front of the O2. Here is the ratio in fractional form:| 2 |
| –– |
| 1 |
2:1
The ChemTeam recommends you always explicitly write the numeral one when it is in the denominator of the ratio.
Example #2: What is the molar ratio between O2 and H2O?
Solution:
The ratio is one-to-two. The 1 is in front of the O2 and the 2 is in front of the H2O. As a fraction, it is:| 1 |
| –– |
| 2 |
1:2
Another way to see a ratio written is like this:
1 is to 2
Example #3: What is the molar ratio between H2 and H2O?
https://froglestmuvol1977.mystrikingly.com/blog/producer-software-download. Solution:
The ratio is:| 2 |
| –– |
| 2 |
As the difficulty level of the problems goes up, the ChemTeam will just use the reduced ratio (assuming you have mastered the earlier materials, such as in this present tutorial). Also be aware, as you examine a solution to a problem by someone else, they may just use the reduced ratio without saying anything about it.
You have been warned!
Example #4: (a) What is the molar ratio between O3 and O2? (b) What is the molar ratio between O2 and O3?
2O3 ---> 3O2
Solution:
For (a), it is:
| 2 |
| –– |
| 3 |
| 3 |
| –– |
| 2 |
However, a warning: people tend to play fast and loose with the molar ratio. The ChemTeam tends to put the first substance mentioned into the numerator. However, other people can be more haphazard. What they do is write a ratio without an explanation for how it got to be that way. What you have to do is figure out from context which number is associated with which substance. You do that by looking at the coefficients of the balanced equation.
Before looking at the following examples, an important point: the coefficients of a reaction only give the ratio in which substances react. They do not in any way tell you HOW MUCH is reacting. This point is elaborated upon in what the ChemTeam believes is the next logical unit from here. However, look at the remaining examples first!
Example #5: N2 + 3H2 ---> 2NH3
Write the molar ratios for (a) N2 to H2 and (b) NH3 to H2.
Solution:
The ratio for (a) is:| 1 |
| –– |
| 3 |
| 2 |
| –– |
| 3 |
Example #6: 2SO2 + O2 ---> 2SO3
Write the molar ratios for (a) O2 to SO3 and (b) SO2 to SO3. Can you win real money on lotsa slots.
Solution:
(a) is:| 1 |
| –– |
| 2 |
| 2 |
| –– |
| 2 |
Example #7: PCl3 + Cl2 ---> PCl5
Write the molar ratios for (a) PCl3 to Cl2 and (b) PCl3 to PCl5.
Solution:
Both requested ratios are this:| 1 |
| –– |
| 1 |
As the problems get more complex, there will be an interesting error students make when using a 1:1 ratio.
Example #8: 4NH3 + 3O2 ---> 2N2 + 6H2O
Write the molar ratios for (a) NH3 to N2 and (b) H2O to O2.
Solution:
(a):| 4 |
| –– |
| 2 |
(b):
| 6 |
| –– |
| 3 |
Note that both ratios can be reduced.
Eventually, ratios like the above will be used in calculations. You may use the unreduced ratio or the reduced ratio in the actual calculation. The ChemTeam's position is that it doesn't matter and so NEVER deducted points if the unreduced ratio was used. However, there are teachers who insist on the reduced ratio being used. Make sure you know what your teacher wants you to do.
Example #9: Fe2O3 + 3CO ---> 2Fe + 3CO2
Write the molar ratios for (a) CO to CO2 Uctox 2 5 4 – full featured invoicing app. and (b) Fe to CO.
Solution:
(a):
| 3 |
| –– |
| 3 |
(b):
| 2 |
| –– |
| 3 |
Notice that I stopped mentioning things like two-to-four and 2:4. Snap on pc software. Macbook pro nfc. Also, a reminder that you might see something like this:
two is to four
Example #10: In this equation:
C2H6O + 3O2 ---> 2CO2 + 3H2O
what is the mole ratio between O2 and H2O?
(a) 1:1; (b) 3:2; (c) 2:3; (d) 3:3
Solution:
From the coefficients of the equation, the mole ratio is 3:3. However, this reduces to a 1:1 ratio. That means that answer choice (a) would be considered by most teachers to be the correct answer.Please note that using a 3:3 ratio in a calculation is equivalent to using a 1:1 ratio. The same answer is obtained using 3:3 as opposed to using 1:1.
The ChemTeam, when in the classroom (now retired), would use the unreduced ratio in calculations done for teaching purposes. This is because, invariably, if the reduced ratio is used, the question would be asked: 'Where did the 1:1 ratio come from?'
Example #11: Given the balanced equation:
2SO2 + O2 ---> 2SO3
what is the mole ratio of O2 to SO3?
(a) 2:1; (b) 1:2; (c) 2:2; (d) 2:3
Solution:
The correct answer is (b) 1:2.When I saw this problem on Yahoo Answers, the first answer given was 2:1, the reverse of the correct answer. 2:1 is the molar ratio of SO3 to O2.
Make sure to write the numbers of the ratio in the same order as used in the question. The first substance mentioned goes in the numerator, the second mentioned in the denominator.
Example #12: What is the molar ratio between copper(II) sulfate and water in the following compound?
CuSO4⋅ 5H2Ocopper(II) sulfate pentahydrate
Solution:
Notice that this is not a chemical reaction, it is simply a chemical formula of a hydrate. Remember, hydrates have a fixed amount of water per mole of the non-water compound.In this example, the molar ratio is 1:5. For every one mole of CuSO4, there are five moles of water.
Example #13: What is the molar ratio between the anhydrous compound and water for the following hydrates?
(a) CuCl2⋅ 2H2O
(b) MgSO4⋅ H2O
(c) Cr2(SO4)3⋅ 18H2O
Solution:
(a) 1:2 ---> one mole of CuCl2 and two of water
(b) 1:1 ---> one mole of MgSO4 and one of water
(c) 1:18 ---> one mole of Cr2(SO4)3 and eighteen of water
Example #14: What is the molar ratio between potassium carbonate and water in the following compound?
K2CO3⋅ 1.5H2O ---> named potassium carbonate sesquihydrate
Solution:
The ratio is 1 to 1.5. In chemistry, there is a desire to state ratios as small whole numbers, so this ratio would be expressed as 2 to three and this formula could be written:2K2CO3⋅ 3H2O
There is nothing whatsoever wrong with the 1 to 1.5 ratio. It's just that there is a desire within the chemistry community to use ratios expressed as small whole numbers.
Example #15: What is the molar ratio between calcium sulfate and water in the following compound?
CaSO4⋅ 0.5H2O ---> named calcium sulfate hemihydrate
Solution:
In small whole numbers, the ratio is 2:1 and the formula can be written thusly:2CaSO4⋅ H2O
| Noun | 1. | molar - grinding tooth with a broad crown; located behind the premolars tooth - hard bonelike structures in the jaws of vertebrates; used for biting and chewing or for attack and defense wisdom tooth - any of the last 4 teeth on each side of the upper and lower jaw; the last of the permanent teeth to erupt (between ages 16 and 21) |
| Adj. | 1. | molar - of or pertaining to the grinding teeth in the back of a mammal's mouth; 'molar teeth' |
| 2. | molar - designating a solution containing one mole of solute per liter of solution | |
| 3. | molar - containing one mole of a substance; 'molar weight' | |
| 4. | molar - pertaining to large units of behavior; 'such molar problems of personality as the ego functions'--R.R. Hunt psychological science, psychology - the science of mental life molecular - relating to simple or elementary organization; 'proceed by more and more detailed analysis to the molecular facts of perception'--G.A. Miller |
) noun
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