Transcript 861-stoic_two

REACTION STOICHIOMETRY(II) FACTOR LABEL LOGIC
2 H2(g) + O2 (g) 2 H20(g)
1) CALCULATE THE YIELD OF OXYGEN IN GRAMS IF 4.0
GRAMS OF WATER IS CONSUMED IN THE ABOVE BALANCED
REACTION.
KNOWN
4.O g H2O
( ) ( )( )
1 mol H2O
2 mol H2O
36 g O2
18 gH2O
1 mol O2
1 mol H2O
CONVERT KNOWN TO
MOLES FROM GRAMS,
GRAMS CANCEL.
MOLAR MASS OF O2 IS
18 G/MOL. GIVES
MOLES OF KNOWN.
MOLES =
MASS
MOLAR MASS
MOLE RATIO: RATIO
MOLES OF OBJECTIVE
TO MOLES OF KNOWN.,
USE COEFFICIENTS OF
BALANCED REACTION.
THIS STEP GIVES MOLES
OF OBJECTIVE.
=
OBJECTIVE
16 g H2O
CONVERT MOLES OF
OBJECTIVE TO GRAMS.
THIS STEP GIVES GRAMS
OF OBJECTIVE, WHICH
THE QUESTION CALLED
FOR
REACTION STOICHIOMETRY FACTOR LABEL LOGIC
2 KClO3  3 O2 (g) + 2 KCl
5) CALCULATE THE YIELD OF OXYGEN IN STP LITERS IF 254
GRAMS OF POTASSIUM CHLORATE IS DECOMPOSED IN THE
ABOVE BALANCED REACTION.
KNOWN
245 g KClO3
( ) ( )( )
1 mol KClO3
3 mol O2
22.4 L O2
122.6 KClO3 g
2 mol KClO3
1 mol O2
MOLE RATIO: RATIO
MOLES OF OBJECTIVE
TO MOLES OF KNOWN.,
USE COEFFICIENTS OF
BALANCED REACTION.
THIS STEP GIVES MOLES
OF OBJECTIVE.
=
OBJECTIVE
67.2 L O2
CONVERT MOLES OF
OBJECTIVE TO LITERS OF
GAS (I MOLE = 22.4 L)
AT STP.
REACTION STOICHIOMETRY FACTOR LABEL LOGIC
2 CH3OH + 3 O2 (g)  2 CO2 (g) + 4 H2O
2) CALCULATE THE TOTAL MASS OF PRODUCTS FORMED
FROM 1 MOLE OF METHANOL.
KNOWN
1 MOLE CH3OH
KNOWN
1 MOLE CH3OH
( )( ) =
2 mol CO2
44. g CO2
2 MOLE CH2OH
1 mol CO2
( )( )
4 mol H2O
18. g H2O
2 MOLE CH2OH
1 mol H2O
OBJECTIVE
44 g L CO2
=
OBJECTIVE
36 g L H2O
THE SUM OF BOTH
PRODUCTS IS 80. g