0
You don't need moles to solve stoichiometry problems. What you do need to do is to turn things (amounts) into the same nomenclature. If you want to turn grams into liters you need to go through several steps to get from grams to liters. For example if you have 20 grams of a substance and the atomic weight (from the Periodic Table) of one molecule of the substance is 40 grams, you need to convert to milligrams. 40 grams = 40,000 mg (1gm=1000mg). So divide 40,000mg by 40 gm. 20gm = 40,000 mg / 40 mg. The grams cancel each other out and you're left with 20 x 40,000 mg / 40. Now you need to get rid of the milligrams. 1 mg = 1 ml so continue with your problem by dividing 40,000 ml by 40,000 mg. Now the mg's cancel each other out and you have 20 x 40,000 x 40,000 ml divided by 40 x 40,000. Now turn ml into liters. 1000 ml = 1 liter so add to your equation 40,000 ml = 10 liters. The ml cancel each other out and you have: 20 x 40,000 x 40,000 x 10 divided by 40 x 40,000 x 40,000. The two 40,000's on top cancel out the two 40,000's on the bottom so you have 20 x 10 divided by 40 which = 200 divided by 40 which equals 5 liters. Divide by 5 and you get 1 liter. The trick is to draw a long line and put the multipliers on top and the divisors below with up and down lines between the sections. If there is something on top that is also on the bottom, they cancel each other out. That can be numbers or units of measurements. This method allows you to convert almost anything to anything else. All you have to know are the conversion numbers (like how many killograms = 1 pound). As you can see, you can even go from metric to US numbers and from solids to liquids. Good luck!
Wiki User
∙ 15y ago
Add your answer:
Earn +20 pts
Why do you need a balanced chemical equation to do sticiometric problems?
Do you mean stoichiometry? The equations need to be balanced so they are stable. They just need to be balanced...
How many milliliters of 0.248M HCl are needed to react with 1.36 grams of zinc to produce hydrogen?
First, write a balanced equation for this reaction. The reactants are HCl and Zn and the products are ZnCl2(aq), and H2(g). For how to write a balanced equation, see the Related Questions to the left. Then, convert the grams of Zn into moles of Zn. To do that, see the Related Questions to the left. Then use stoichiometry to determine how many moles of HCl are necessary to react with that number of moles of Zn. See the Related Questions to the left for how to solve stoichiometry problems. Finally, determine how many milliliters of solution you need to get that many moles of HCl. To do that, use this equation: number of moles = number of liters * molarity
How do you solve stoichiometry problems?
To solve stoichiometry problems, you must first do two very important things.1) Write a balanced equation for the reaction.2) Convert all amounts of products and/or reactants in the question into moles.To find out how to do both of these see the Related Questions links to the left of this answer. (Note that if the question involves gases, and the amount of gas is given as a volume, you need to use the Ideal Gas Law. How to do that is also listed under the Related Questions).Once all quantities have been converted to moles and you have a balanced reaction, you are ready to actually use stoichiometry. The idea of stoichiometry is really quite simple. The coefficients (or numbers) in front of each reactant and product in the balanced chemical reaction tells you the ratio of how much of each you will react/produce. Let's take a simple example: the reaction of hydrogen gas (H2) with oxygen gas (O2) to form water (H2O). 2H2 + O2 ---> 2H2O In the balanced reaction, there is a 2 in front of the H2, and although nothing is written, that means that there is really 1 in front of O2, and a 2 in front of H2O. Stoichiometry tells us that because of the way the numbers in balanced reaction came out, we need two molecules of H2 to react with each one molecule of O2, and also, that this will form 2 molecules of water. I can say the same thing using moles: For each mole of O2 I react, I need 2 moles of H2, and I will produce 2 moles of O2. All I'm using is the ratio of the coefficients from the balanced reaction. That is stoichiometry! So, using this I can say things like: -- If I reaction 0.5 moles of O2 completely, I will make 1 mole of water-- If I made 4 moles of water, then I consumed 4 moles of H2 and 2 moles of O2.-- If I want to completely react 5 moles of H2, then I need 2.5 moles of O2 (and I will get 5 moles of H2O). Makes sense? The ratio of H2 to O2 to H2O is 2:1:2, and that always holds for this reaction.Now let's make it a bit more complicated.--Problem: If I burn 10 grams of methane, how many grams of CO2 will be produced?-- Answer: As I said, to solve this problem we need two things: a balanced reaction, and to convert all quantities to moles. First, let's write a balanced reaction. In this reaction, methane gas (CH4) gets burned in oxygen (O2) to form carbon dioxide (CO2) and water vapor (H2O). The balanced reaction is:CH4 + 2O2 --> CO2 + 2H2ONotice the ratio is now 1:2:1:2 (reading the reaction from left to right). So that tells me for every mole of CH4 I react, I need 2 moles of O2, and I will get out 1 mole of CO2 and 2 moles of H2O.Now, I need to convert the 10 grams of methane into moles, because stoichiometry only works for moles and NOT grams! So I use the molar mass of CH4, which is 12.011+4*1.0079 = 16.0426 grams per mole. So to convert to moles, I just divide: 10 grams ÷ 16.0426 gram/mole = 0.6233 moles From the stoichiometry, I now know that if I react 0.6233 moles of methane, I will need twice that many moles of oxygen, or 1.2467 moles O2, and I will get 0.6233 moles of CO2 and 1.2467 moles of H2O as products. But the question asked for a number of grams of CO2, not moles. So once I'm done using stoichiometry, I convert back to grams, now using the molar mass of CO2 (which is 12.011 + 2*15.999 = 44.009 g/mol). So 0.6233 moles of O2 is: 0.6233 moles * 44.009 grams/mole = 27.4308 grams of CO2 Notice that the ratio of moles of CH4 to CO2 is 1 to 1, but the ratio of the weights is totally different. Remember, STOICHIOMETRY ONLY WORKS ON MOLES! I can also find how many grams of water I'll produce, just for fun! The molar mass of water is 15.999 + 2*1.0079 = 18.0148 g/mol. So to convert 1.2467 moles H2O to grams: 1.2467 moles * 18.0148 gram/mole = 22.4591 grams of H2Oto answer stoichiometry problems there are several ways.one way is the mole concept(mol)-always remember Avogadro's number which is 6.02x10^23.eg. how many atoms are there in 1 mol of glucose(C6H12O6)?1 mol C6H13O6 x 6.02x10^23= 6.02x19^231 mol C6H12O6cancel 1 mol C6H12O6 leaving the answer.
How many moles of PCl5 can be produced from 24 grams of P4?
Assuming that you are combining the P4 with Cl2 and there is a suffiecient quantity of Cl2 for the P4 to completely react, you will first need a balanced equation which is P4 + 10Cl2 -> 4PCl5. From there, it's mostly stoichiometry. Take the 24g of P4, divide by the molar mass (123.88g/mol) to get the number of moles of P4 that you have (0.194). You then have to convert, using the balanced equation, from moles of P4 to moles of PCl5, in this case multiplying by 4. That will give you the number of moles of PCl5. The stoichiometry should look something like this 24.0 g P4 x (1 mol P4/123.88g P4) x (4 mol PCl5/1 mol P4).
If .3 mole of N2 are reacted with .6 mole of H2 what mass of NH3 could form the formula N2 plus 3 H2 makes 2 NH3 The answer to the problem is 6.8 but don't know how to get that?
First you have to find the limiting reactant. You have .3 moles of nitrogen and .6 moles of hydrogen, but you don't know which one is going to run out first.In any of these stoichiometry problems, you need to write down the formula:N2 + 3H2 → 2NH3Take both nitrogen and hydrogen and figure out how much ammonia is made alone..6 moles Hydrogen ÷ 3 moles hydrogen × 2 moles ammonia = .4 moles ammonia made.3 moles Nitrogen ÷ 1 mole nitrogen × 2 mole ammonia = .6 moles ammonia madeNow you figured out that hydrogen is the limiting reactant and the nitrogen is the excess because less ammonia is made using hydrogen. This measurement is what you will be using for the rest of the problem.Take the limiting reactant and use stoichiometry to find how much ammonia can be made.You could start with .6 moles of hydrogen and do the same conversion as above, but add the step of converting to grams. Or, since you already found out that .4 moles ammonia is made, just convert it to grams. The molecular mass of ammonia is 17.0 grams..4 moles ammonia × 17.0 grams = 6.8 grams ammonia
Why do you need a balanced chemical equation to do sticiometric problems?
Do you mean stoichiometry? The equations need to be balanced so they are stable. They just need to be balanced...
How many milliliters of 0.248M HCl are needed to react with 1.36 grams of zinc to produce hydrogen?
First, write a balanced equation for this reaction. The reactants are HCl and Zn and the products are ZnCl2(aq), and H2(g). For how to write a balanced equation, see the Related Questions to the left. Then, convert the grams of Zn into moles of Zn. To do that, see the Related Questions to the left. Then use stoichiometry to determine how many moles of HCl are necessary to react with that number of moles of Zn. See the Related Questions to the left for how to solve stoichiometry problems. Finally, determine how many milliliters of solution you need to get that many moles of HCl. To do that, use this equation: number of moles = number of liters * molarity
How do you solve stoichiometry problems?
To solve stoichiometry problems, you must first do two very important things.1) Write a balanced equation for the reaction.2) Convert all amounts of products and/or reactants in the question into moles.To find out how to do both of these see the Related Questions links to the left of this answer. (Note that if the question involves gases, and the amount of gas is given as a volume, you need to use the Ideal Gas Law. How to do that is also listed under the Related Questions).Once all quantities have been converted to moles and you have a balanced reaction, you are ready to actually use stoichiometry. The idea of stoichiometry is really quite simple. The coefficients (or numbers) in front of each reactant and product in the balanced chemical reaction tells you the ratio of how much of each you will react/produce. Let's take a simple example: the reaction of hydrogen gas (H2) with oxygen gas (O2) to form water (H2O). 2H2 + O2 ---> 2H2O In the balanced reaction, there is a 2 in front of the H2, and although nothing is written, that means that there is really 1 in front of O2, and a 2 in front of H2O. Stoichiometry tells us that because of the way the numbers in balanced reaction came out, we need two molecules of H2 to react with each one molecule of O2, and also, that this will form 2 molecules of water. I can say the same thing using moles: For each mole of O2 I react, I need 2 moles of H2, and I will produce 2 moles of O2. All I'm using is the ratio of the coefficients from the balanced reaction. That is stoichiometry! So, using this I can say things like: -- If I reaction 0.5 moles of O2 completely, I will make 1 mole of water-- If I made 4 moles of water, then I consumed 4 moles of H2 and 2 moles of O2.-- If I want to completely react 5 moles of H2, then I need 2.5 moles of O2 (and I will get 5 moles of H2O). Makes sense? The ratio of H2 to O2 to H2O is 2:1:2, and that always holds for this reaction.Now let's make it a bit more complicated.--Problem: If I burn 10 grams of methane, how many grams of CO2 will be produced?-- Answer: As I said, to solve this problem we need two things: a balanced reaction, and to convert all quantities to moles. First, let's write a balanced reaction. In this reaction, methane gas (CH4) gets burned in oxygen (O2) to form carbon dioxide (CO2) and water vapor (H2O). The balanced reaction is:CH4 + 2O2 --> CO2 + 2H2ONotice the ratio is now 1:2:1:2 (reading the reaction from left to right). So that tells me for every mole of CH4 I react, I need 2 moles of O2, and I will get out 1 mole of CO2 and 2 moles of H2O.Now, I need to convert the 10 grams of methane into moles, because stoichiometry only works for moles and NOT grams! So I use the molar mass of CH4, which is 12.011+4*1.0079 = 16.0426 grams per mole. So to convert to moles, I just divide: 10 grams ÷ 16.0426 gram/mole = 0.6233 moles From the stoichiometry, I now know that if I react 0.6233 moles of methane, I will need twice that many moles of oxygen, or 1.2467 moles O2, and I will get 0.6233 moles of CO2 and 1.2467 moles of H2O as products. But the question asked for a number of grams of CO2, not moles. So once I'm done using stoichiometry, I convert back to grams, now using the molar mass of CO2 (which is 12.011 + 2*15.999 = 44.009 g/mol). So 0.6233 moles of O2 is: 0.6233 moles * 44.009 grams/mole = 27.4308 grams of CO2 Notice that the ratio of moles of CH4 to CO2 is 1 to 1, but the ratio of the weights is totally different. Remember, STOICHIOMETRY ONLY WORKS ON MOLES! I can also find how many grams of water I'll produce, just for fun! The molar mass of water is 15.999 + 2*1.0079 = 18.0148 g/mol. So to convert 1.2467 moles H2O to grams: 1.2467 moles * 18.0148 gram/mole = 22.4591 grams of H2Oto answer stoichiometry problems there are several ways.one way is the mole concept(mol)-always remember Avogadro's number which is 6.02x10^23.eg. how many atoms are there in 1 mol of glucose(C6H12O6)?1 mol C6H13O6 x 6.02x10^23= 6.02x19^231 mol C6H12O6cancel 1 mol C6H12O6 leaving the answer.
How many moles of PCl5 can be produced from 24 grams of P4?
Assuming that you are combining the P4 with Cl2 and there is a suffiecient quantity of Cl2 for the P4 to completely react, you will first need a balanced equation which is P4 + 10Cl2 -> 4PCl5. From there, it's mostly stoichiometry. Take the 24g of P4, divide by the molar mass (123.88g/mol) to get the number of moles of P4 that you have (0.194). You then have to convert, using the balanced equation, from moles of P4 to moles of PCl5, in this case multiplying by 4. That will give you the number of moles of PCl5. The stoichiometry should look something like this 24.0 g P4 x (1 mol P4/123.88g P4) x (4 mol PCl5/1 mol P4).
How can problems in yosemite be slove?
Problems in Yosemite can be solved with the help of park visitors and volunteers. Volunteers help maintain trails and other tasks rangers need help with. Park visitors can help by leaving no trace and following all park rules.
How do you slove for a spherical triangle?
A spherical triangle is not a question or a puzzle that you can solve, or even slove! You need to specify what information you have and what you wish to solve for: angles, lengths of sides, perimeter, area and so on.
If .3 mole of N2 are reacted with .6 mole of H2 what mass of NH3 could form the formula N2 plus 3 H2 makes 2 NH3 The answer to the problem is 6.8 but don't know how to get that?
First you have to find the limiting reactant. You have .3 moles of nitrogen and .6 moles of hydrogen, but you don't know which one is going to run out first.In any of these stoichiometry problems, you need to write down the formula:N2 + 3H2 → 2NH3Take both nitrogen and hydrogen and figure out how much ammonia is made alone..6 moles Hydrogen ÷ 3 moles hydrogen × 2 moles ammonia = .4 moles ammonia made.3 moles Nitrogen ÷ 1 mole nitrogen × 2 mole ammonia = .6 moles ammonia madeNow you figured out that hydrogen is the limiting reactant and the nitrogen is the excess because less ammonia is made using hydrogen. This measurement is what you will be using for the rest of the problem.Take the limiting reactant and use stoichiometry to find how much ammonia can be made.You could start with .6 moles of hydrogen and do the same conversion as above, but add the step of converting to grams. Or, since you already found out that .4 moles ammonia is made, just convert it to grams. The molecular mass of ammonia is 17.0 grams..4 moles ammonia × 17.0 grams = 6.8 grams ammonia
Why do you need a balanced equation to do stoichiometry?
A chemical equation must respect the law of mass conservation.
How do you slove negative 2w equals r plus s?
Not sure that you can slove anything. -2w = r + s is one linear equation in 3 unknown variables. You need three independent equations in 3 variables to be able to solve them.
To calculate the molarity of a solution, you need to know the moles of solute and the?
You need to know the moles of solute and the VOLUME of SOLUTION.
How many moles of KCI would be dissolved in 4 liters of water to make a 2 Molar solution?
We need 8 moles potassium chloride.
The sterile solution used to rinse contact lenses can be made by dissolving 400 mg of NaCl in sterile water and diluting to 100 mL. what is the molarity of this solution?
First, find the moles of NaCl. Because you have 400 milligrams of NaCl convert to grams by dividing 1000mg. 400mg/1000mg = 0.400 grams of NaCl. Now we need to convert to moles. For every mole of NaCl there is 58.44 grams. (22.99g Na + 35.45 g Cl) so using stoichiometry (grams cancel) I get .0068 moles of NaCl. Conver 100 mL to L by dividing by 1000mL. Therefore there is .001 L in the solution. Molarity is moles per Liter. So 0.0068 mols of NaCl / 0.001 L = 6.84 M
