Atoms and moles -Chem- EASY BEST ANSWER!!?

Hello does anyone know the answer to these problems because it'll earn best answer. my answers were wrong.








How many atoms of hydrogen are contained in 100g of methane (CH4)


My Answer: There are 25 atoms of Hydrogen in 100 grams of methane.


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How many moles of P4O10 are produced when we react 8 moles of phosphorous with oxygen?


My Answer: 1.6 Moles

Atoms and moles -Chem- EASY BEST ANSWER!!?
I have checked all of your last questions and saw that all of them are in the same type:


"Mole - Mass - Number of Particles" relationship.





Therefore, rather that to give individual answers, it will be better to teach the concept so that you can solve the questions of the same type.


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Elements have "symbols" and compounds have " formulas". The symbol of an element or the formula of a compound represents their one mole.





For example;


- H2O = 1 mol water, in which 1 mol O and 2 mol H are present.


- NH3 = 1 mol ammonia, in which 1 mol N and 3 mol H are present.





In a chemical equation;


- N2 + 3H2 ------%26gt; 2NH3


1 mol nitrogen (N2) reacts with 3 moles hydrogen (H2) and produces 2 moles of ammonia (NH3).





Now, the number of particles:


1 mole always represents a specific number, called Avogadro's number that is 6.02 x 10^23.





For an element:


1 mole of any element contains Avogadro's number of "atoms" of that element.


1 mol Fe = 6.02 x 10^23 Fe atoms


1 mol Mg = 6.02 x 10^23 Mg atoms.





For a compound:


1 mole of any molecular (covalent) compound contains Avogadro's number of "molecules" of that compound.


1 mol NH3 = 6.02 x 10^23 NH3 molecules.


1 mol H2O = 6.02 x 10^23 H2O molecules.





1 mole of any ionic compound contains Avogadro's number of "formula units" of that compound.


1 mol NaCl = 6.02 x 10^23 NaCl formula units.


1 mol CaO = 6.02 x 10^23 CaO formula units.





Now, we have come to the mass relationship:





The mass of 1 mole of any element is numerically equal to its atomic mass expressed in grams.


For example; atomic mass of Fe is 56. If you have 56 g of iron, this means that you have 1 mole of iron.


Atomic mass of sodium is 23. So, 23 g Na = 1 mole.





If you combine the number of particles, you get 3 relationship:


1 mol Fe = 56 g = 6.02 x 10^23 atoms of Fe


1 mol Na = 23 g = 6.02 x 10^23 atoms of Na


1 mol Mg = 24 g = 6.02 x 10^23 atoms of Mg





The mass of 1 mole of any compound is numerically equal to its formula mass expressed in grams. For example;





H2SO4 formula stands for 1 mol sulfuric acid, in which there are 2 moles of H, 1 mole of S and 4 moles of O. Their atomic masses are 1, 32 and 16 respectively. Therefore, the formula


mass of H2SO4 : (2x1) + 32 + (4x16) = 2 + 32 + 64 = 98





If you have 98 g of H2SO4, this means that you have 1 mole of H2SO4.





Now, lets apply what we have learnt to your questions.





(1) The formula mass of methane (CH4) = 12 + 1x4 = 16


This means that 16 g of CH4 = 1 mole or in other words,


the molar mass of CH4 = 16 g/mol.


16 g CH4 = 1 mol and it contains 4 moles of H atom


then, 100 g CH4 will contain;


4 mol H x (100 g CH4 / 16 g CH4) = 25 mol H atom.


But the question requires "the number of atoms".


1 mole of any element has Avogadro's number of atoms, therefore;


25 mol H x 6.02x10^23 atom/mol = 150.5x10^23


= 1.505x10^25 atom H





(2) Although the question implies a reaction, there is no need to write an equation of the reaction.


The formula of P4O10 states that you will need 4 mol P and 10 mol O to make 1 mol P4O10.


In this question the limiting substance is P (its amount is specified).


Since 4 mol P produces 1 mol P4O10


8 mol P produces (P is doubled, P4O10 is also doubled) 2 mol P4O10. Or,


1 mol P4O10 x (8 mol P / 4 mol P) = 2 mol P4O10.





I think, it is clear and I believe that you can solve your other questions. If not, please inform me. Since you are not one of my contacts, from time to time I look at your profile page to investigate your new questions. Because in answering the questions, the priority is given to those who appreciate my answers.
Reply:25 is the amount of grams of hydrogen, not atoms. Convert 25g of hydrogen to moles, then to atoms using avagrados number. The answer should be 1.49 times 10 to the 24 atoms.
Reply:A lot more hydrogen's than that!





100g CH4 X 1mol/48.42g X 4mol H/1mol C X 6.022 X 10^23





= 4.97 X 10^24 atoms of hydrogen.





Need balanced equation for 2.