Stoichiometry
Stoichiometry notes
The Mole Concept
2. like a dozen means 12
3. mole = 6.02 x 1023 [this number is known as Avogadro’s #]
4. useful for discussion of very small items (atoms, molecules...)
a. 1 mole of any element = 6.02 x 1023 atoms of that element
b. 2.0 mol Na x 6.02 x 1023 atoms/ 1 mol Na = 1.2 x 1024 atoms Na
c. 4.5x1023 atom He x 1 mol He/6.02 x 1023 atoms He = .75 mol He
b. 1 mole Na = 23.0 g
c. 2.5 mol C x 12.0 g C/ 1 mol C = 30. g C
d. 120 g Ca x 1 mol Ca/ 40.1 g Ca = 3.0 mol Ca
b. 1.0 mol of NaOH = 6.02 x 1023 MOLECULES of NaOH ---(actually
should be formula units since NaOH is ionically bonded and not a true molecule)
c. 2.0 mol KCl x 6.02 x 1023 molecules (formula units) = 12 x 1023 form unit
d. 6.0 x 1024 molecules water x 1 mol water/ 6.02 x 1023 molecules= 10. mol water
compound (from PT)
b. 1 mol Water = 18.0 g water
c. 2.0 mol water x 18.0 g water/ 1 mol water = 36 g water
d. 65g water x 1 mol water/ 18.0 g water = 3.6 mol water
b. 1 molecule C6H5O = 6 atoms C, 5 atoms H, 1 atom O
c. 1 mol C6H5O = 6 mol C, 5 mol H, 1 mol O
d. # atoms of each element in 3.2 mol H2O?
3.2 mol H2O x (6.02 X 1023 molecules H2O/ 1 mol H2O) x (2 atoms H/1 molecule H2O) = 3.9 x 1024 atoms H {and similarly 2.0 x 1024 atoms O}
e. alternately the problem may be solved this way
3.2 mol H2O x (2 mol H/1 mol H2O) x (6.02 x 1023 atoms H/ 1 mol H) =
3.9 x 1024 atoms H
b. NaCl → Na+ + Cl- - for each NaCl compound (formula unit) 2 particles will exist (1 Na and 1 Cl)
c.1 mol K2SO4 = (2K+ and 1 SO4-) 3 mole particles
d. 2.0 mol K2SO4 = ? ions and ? ions potassium
2.0 mol K2SO4 x (3 mol ions/1 mol K2SO4 ) x (6.02 x 1023 ions/1 mol ions) =
3.6 x 1024 ions total
2.0 mol K2SO4 x (2 mol K+ ions/ 1 mol K2SO4) X (6.02 x 1023 ions/ 1 mol ions)
= 2.4 x 1024 K+ ions
how many grams of water produced by combustion of 1.0 g glucose?
1.0 g C6H12O6 x 1 mol/180.0 g x 6 mol HOH/1 mol glucose X 18 g HOH/1 mol
HOH = 0.60 g wate
The Mole Concept
A. Mole
1. definition: a word that means a number2. like a dozen means 12
3. mole = 6.02 x 1023 [this number is known as Avogadro’s #]
4. useful for discussion of very small items (atoms, molecules...)
B. Relationships
1. moles to atoms of elementsa. 1 mole of any element = 6.02 x 1023 atoms of that element
b. 2.0 mol Na x 6.02 x 1023 atoms/ 1 mol Na = 1.2 x 1024 atoms Na
c. 4.5x1023 atom He x 1 mol He/6.02 x 1023 atoms He = .75 mol He
moles to grams of element
a. 1 mole of any element = atomic mass of element in grams (from PT)b. 1 mole Na = 23.0 g
c. 2.5 mol C x 12.0 g C/ 1 mol C = 30. g C
d. 120 g Ca x 1 mol Ca/ 40.1 g Ca = 3.0 mol Ca
] moles to molecules
a. 1 mole of any compound = 6.02 x 1023 molecules of that compoundb. 1.0 mol of NaOH = 6.02 x 1023 MOLECULES of NaOH ---(actually
should be formula units since NaOH is ionically bonded and not a true molecule)
c. 2.0 mol KCl x 6.02 x 1023 molecules (formula units) = 12 x 1023 form unit
d. 6.0 x 1024 molecules water x 1 mol water/ 6.02 x 1023 molecules= 10. mol water
mole to grams of molecules
a. 1 mole of any molecule or compound = molecular (formula) mass of thatcompound (from PT)
b. 1 mol Water = 18.0 g water
c. 2.0 mol water x 18.0 g water/ 1 mol water = 36 g water
d. 65g water x 1 mol water/ 18.0 g water = 3.6 mol water
moles to atoms of a molecule
a. relationship between atoms within a molecule is given by the subscriptb. 1 molecule C6H5O = 6 atoms C, 5 atoms H, 1 atom O
c. 1 mol C6H5O = 6 mol C, 5 mol H, 1 mol O
d. # atoms of each element in 3.2 mol H2O?
3.2 mol H2O x (6.02 X 1023 molecules H2O/ 1 mol H2O) x (2 atoms H/1 molecule H2O) = 3.9 x 1024 atoms H {and similarly 2.0 x 1024 atoms O}
e. alternately the problem may be solved this way
3.2 mol H2O x (2 mol H/1 mol H2O) x (6.02 x 1023 atoms H/ 1 mol H) =
3.9 x 1024 atoms H
mole to particles
a. ionic substances may be identified by their particlesb. NaCl → Na+ + Cl- - for each NaCl compound (formula unit) 2 particles will exist (1 Na and 1 Cl)
c.1 mol K2SO4 = (2K+ and 1 SO4-) 3 mole particles
d. 2.0 mol K2SO4 = ? ions and ? ions potassium
2.0 mol K2SO4 x (3 mol ions/1 mol K2SO4 ) x (6.02 x 1023 ions/1 mol ions) =
3.6 x 1024 ions total
2.0 mol K2SO4 x (2 mol K+ ions/ 1 mol K2SO4) X (6.02 x 1023 ions/ 1 mol ions)
= 2.4 x 1024 K+ ions
Stoichiometry example
C6H12O6(s) + 6 O2(g) ----> 6 CO2(g) + 6 H2O(l)how many grams of water produced by combustion of 1.0 g glucose?
1.0 g C6H12O6 x 1 mol/180.0 g x 6 mol HOH/1 mol glucose X 18 g HOH/1 mol
HOH = 0.60 g wate
The A2 gas of 10 mL just reacts with 15 mL of B2 gas to form 10 mL of AxBy gas at the same temperature and pressure. What is the value of x and y?
BalasHapusThe ratio of gas volume A2 to gas B2 and gas AxBy is 10 mL: 15 mL: 10 mL = 2: 3: 2. The ratio of gas
Hapusvolume is equal to the ratio of the reaction coefficient. Thus, the reaction equation becomes:
2 A2 (g) + 3 B2 (g) → 2 AxBy
Value x = 2 and value y = 3.
Can you explain me about the law of conservation of mass in chemistry ? What is the sound of the law ?
BalasHapusThe law of conservation of mass or principle of mass conservation states that for any system closed to all transfers of matter and energy, the mass of the system must remain constant over time, as system mass cannot change quantity if it is not added or removed. Hence, the quantity of mass is "conserved" over time. The law implies that mass can neither be created nor destroyed, although it may be rearranged in space, or the entities associated with it may be changed in form, as for example when light or physical work is transformed into particles that contribute the same mass to the system as the light or work had contributed. Thus, during any chemical reaction, nuclear reaction, or radioactive decay in an isolated system, the total mass of the reactants or starting materials must be equal to the mass of the products.
Hapusplease explane me about law in the stoichiometry?
BalasHapus1. The Law of Conservation of Mass (Lavoisier Law)
Hapus"The mass of the reaction substance is equal to the mass of the substance after the reaction"
2. Fixed Law (Proust Law)
"The mass ratio of the constituent elements is always, whatever is made in different ways"
3. Law of Volume Reset (Gay Lussac Law)
Applies only to gas phase related chemical reactions
"At the same temperature and pressure, the ratio of the reactant gas volume to the gas volume of the reaction product is an integer and simple (equal to the ratio of the reaction)"
4. Avogadro's Law
Applies only to gas phase related chemical reactions
"At the same temperature and pressure, volumes of gas equal to the same number of moles"
Hi, with the coefficient in front of reactan and product in equation, i always thought they represented the number of molecules of these substance. For example 2Na + Cl would mean 2 molecules of sodium reacting with one molecules of oxigen. How can i reconcile that with the concept of stoichiometric, or is that completely wrong?
BalasHapusThanks
In your problem you put Chlorine gas but you said "reacts with oxygen" everythjng else in your problem is correct except for that piece. Let me put it into a problem. H2 + Cl2 = 2HCl because hydrogen and chlorine are diatomic so together they would form 2 molecules of HCl.
HapusHope this helped.
what is the conclusion about your stoichiometry's article
BalasHapuswhere the total mass of the reactants equals the total mass of the products leading to the insight that the relations among quantities of reactants and products typically form a ratio of positive integers. This means that if the amounts of the separate reactants are known, then the amount of the product can be calculated. Conversely, if one reactant has a known quantity and the quantity of product can be empirically determined, then the amount of the other reactants can also be calculated.
HapusCompute Mr. from the following substances.1.P42.Fe2 (SO4) 33.Ca3 (PO4) 2
BalasHapusA.
HapusFe= 56 x 2 = 112
S= 32 x 3 = 96
O= 16 x 12 = 192
Total = 400
B.
Ca= 40 x 3 = 120
P= 31 x 2= 62
O= 16 x 8= 128
Total = 310
C.
K=39
Al= 27
S=32 x 2=64
O=16 x 8= 128
Total = 258
D.
K= 39 x 4 = 156
Fe= 56
C=12 x 6 = 72
N= 14 x 6 = 84
Total = 368
Whether the time difference may be shown in stoichiometry?
BalasHapus
HapusNo, since stoichiometry is a science that comprises and quantifies quantitative relationships of reactants and products in chemical reactions
Mention another example of stoichiometry?
BalasHapus
HapusA. Charging battery
B. Capillarity Symptoms in air
C. Gas Kinetic Theory
D. Calorimeter
E. Heating / cooking air