Chem 103 - Module 5/ 12
Questions and Complete Correct
Answers
Ideal Gases - -1. Have no volume
2. Are not attracted or repulsed by one another
-Gas Laws for Ideal Gases - -P1V1= P2V2,
V1/T1 = V2/T2,
P1V1/T1 = P2V2/T2,
PV=nRT,
molar mass= gRT/PV,
D=(P)(molar mass)/RT,
V1/n1 = V2/n2
PM (molar mass) = dRT
-Units - -P= pressure (atm) V= volume (L) T= temperature (K) n= number of
moles R= gas constant (0.0821) g= grams D= density (g/L)
If R is present--> P must be in atm and V must be in L
If R is not present--> can be any units but they have to match
-Relationship between gas variables - -If variables are on the same side of
the equation, they have an inverse relationship
If they are on opposite sides of the equation, they have a direct relationship
Graphs; Linear = Direct
Curve = Inverse
-Empirical Formula - -Assume 100g
2. % --> g
3. g --> mol (if g originally given and not mass% --> start at step 3!)
4. Write chemical formula; divide by smallest number of moles
5. Fractions: 0.5 = 1/2 > x2; 0.33 or 0.66 = 1/3 or 2/3 > x3; 0.25 or 0.75 =
1/4 or 3/4 > x4
-Molecular Formula - -1. Determine ratio = molar mass molecular formula/
molar mass empirical formula
2. Take empirical formula and multiply each subscript by the number from
above ratio
-Partial Pressure Equations - -Ptotal = P1 + P2...
X1 (mol fraction) = n1/ntotal = P1/Ptotal
P1= X1Ptotal
PtotalV=ntotalRT
Questions and Complete Correct
Answers
Ideal Gases - -1. Have no volume
2. Are not attracted or repulsed by one another
-Gas Laws for Ideal Gases - -P1V1= P2V2,
V1/T1 = V2/T2,
P1V1/T1 = P2V2/T2,
PV=nRT,
molar mass= gRT/PV,
D=(P)(molar mass)/RT,
V1/n1 = V2/n2
PM (molar mass) = dRT
-Units - -P= pressure (atm) V= volume (L) T= temperature (K) n= number of
moles R= gas constant (0.0821) g= grams D= density (g/L)
If R is present--> P must be in atm and V must be in L
If R is not present--> can be any units but they have to match
-Relationship between gas variables - -If variables are on the same side of
the equation, they have an inverse relationship
If they are on opposite sides of the equation, they have a direct relationship
Graphs; Linear = Direct
Curve = Inverse
-Empirical Formula - -Assume 100g
2. % --> g
3. g --> mol (if g originally given and not mass% --> start at step 3!)
4. Write chemical formula; divide by smallest number of moles
5. Fractions: 0.5 = 1/2 > x2; 0.33 or 0.66 = 1/3 or 2/3 > x3; 0.25 or 0.75 =
1/4 or 3/4 > x4
-Molecular Formula - -1. Determine ratio = molar mass molecular formula/
molar mass empirical formula
2. Take empirical formula and multiply each subscript by the number from
above ratio
-Partial Pressure Equations - -Ptotal = P1 + P2...
X1 (mol fraction) = n1/ntotal = P1/Ptotal
P1= X1Ptotal
PtotalV=ntotalRT
