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MSU / Engineering / CHEM 120 / What is the meaning of limiting reactant?

# What is the meaning of limiting reactant? Description

##### Description: This covers all material (Chapter 3,4,5, and 6) that will show up on the test!
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H+O= acid

## What is the maning of limiting reactant?

Ex. HCL: Hydrochloric acid

Molar Mass

What is the molar mass of C8H18?

8(12.01g/mol) + 18(1.01 g/mol)= 114.22 g/mol

Glucose formula: C6 H12 O6

Therefore 1 mole of Glucose…

Is 6 mole of C

Is 12 mol of H

Is 6 mol of O

Empirical and Molecular formula

Empirical formula: the simplest ratio present

Ex: CH2O

Molecular formula: n (empirical formula)

Ex: C6H12O6 = 6 (CH2O) Don't forget about the age old question of What are the police misconducts identified by ellwyn stoddard?

Molar mass: n (empirical mass)

Ex: (6 x 12.01 g/mol) + (12 x 1.01 g/mol) + (6 x 16.000 g/mol) = 180.16 g/mol (MOLAR MASS)

## What doe electrolytes contain?

We also discuss several other topics like How are the structures of the bones characterized?

Ex. (1 x 12.01 g/mol) + (2 x 1.01 g/mol) + (1 x 16.000 g/mol)= 30.03 g/mol (EMPIRICAL MASS)

Examples: What’s the empirical and molecular formula of the following compound? 26.7% P, 12.2% N, 61.2% Cl Molar Mass: 580 g/mol

Strategy: Assume 100 g of compound

P: 26.7 g; N: 12.2 g; Cl: 61.2 g

P: 26.7 x 1mol/30.97 g =0.862 mol P

N: 12.2 x 1mol/14.01 g =0.864 mol N

Cl: 61.2 x 1mol/35.45 g =1.73 mol Cl

Divide by smallest number: 0.862

P: 0.862/0.862 N: 0.864/0.862 Cl: 1.73/0.862=

P1 N1 C2 ---->> EMPIRICAL FORMULADon't forget about the age old question of How the allocation of resources affects economic well being?

For molecular….

Molar mass= n ( empirical mass)

## How can one compute for glucose?

580 g/mol= n (30.97g/mol + 14.01 g/mol + 2(35.45g/mol)) If you want to learn more check out What is ecological hierarchy?

580 g/mol= n (115 g/mol)

n= 5.04--------> 5

Molecular formula:

=5(empirical formula)

=5( PNCl2)

=P5N5Cl10

Limiting reactant: reactant that is entirely used up and makes less product Theoretical yield: maximum amount you can make Don't forget about the age old question of Where is the temperate broadleaf forest?

Percent reactant: actual yield/ theoretical yield x 100%

Excess reactant: reactant that has left overs

How to balance equations: ____Fe (s) +___ O2 (g) ------>>> ___ Fe2O3 (s) 1. Start with 1.00 mol O2, How many moles Fe needed?

1.00 mol O2 x 4 mol Fe/ 3 mol O2 = 1.33 moles of iron

100.0 g O2 x 1 mol O2/ 32.00 g x 4 mol Fe/ 3 mol O2 x 55.85 g Fe/ 1 mol Fe= 232.7 grams Fe Don't forget about the age old question of Why are the offspring of sexual reproduction not perfect copies of their parents?

3. Start with 32.7 grams O2 with 54.1 grams Fe, How much Fe2O3 possible?

Fe

O2

Fe2O3

Mass before

reaction

54.1 g

32.7 g

0g

Moles before

(54.1x 1 mol)/

55.85g.=0.969

mol

1.02 mol

0 mol

Moles after

0 mol

0.295 mol

0.484 mol

Mole after

reaction

0 mol

0.295x 32.00 g/ 1 mol

0.484 x 159.70g/1 mol

__4__Fe (s) +_3__ O2 (g) ------>>> _2__ Fe2O3 (s)

Chapter 5: Solutions

Solution: homogeneous mixture of solvent and solute

Solvent: large amount of what is dissolving solute (Ex. water)

Solute: smaller quantity

Molarity (M): moles of solute/ L of solution

Ex. 0.500 M NaCl, whats the molarity of Na+ and Cl-?

0.500 M for each

DISSOLVE VS DISSOCIATE

Dissolve: solid and solvent form homogeneous mixture

Dissociate: ionic compound falls apart into ions as it is dissolved in solution

Electrolytes- solution that contains ions

Strong electrolytes: “fully dissociate”

= solution that conducts electricity

Weak electrolytes: “partially dissociates”

Non- electro. : does not dissociate (Ex. sugar, gasoline, oil) ;won’t conduct electricity

NaCl ( table salt ) in H20 will dissociate because it is ionic ( NaCl------>> Na+ + Cl-) C12H24O12 (sugar/sucrose) won't dissociate but will dissolve

Mostly Soluble:

1.anything (anion) with group 1 cation( Li+, Na+, K+) and ammonium 2. anything (cation) with nitrate or acetate

3.Group 17 anion

Exception:Ag+, Hg2^2+, Pb^2+

4.SO4^2-

Mostly insoluble:

1.OH-, S2-

2.CO3^2-, PO4^3-

ACID

*Strong acid: HCl, HI, HNO3, H2SO4, HClO4 (MEMORIZE)

Weak acid: everything else

BASE

Strong base: NaOH, LiOH, KOH, Ca(OH)2

Weak base: NH3

acid+ base-----> H2O +SOH

Strong acid + Strong Base

Ex. HCL + NaOH---> H20 +NaCl

H + Cl + Na+ OH -----> H2O + Na +Cl

CROSS OUT REPEATS!

H+ OH----> H2O

OXIDATION

Oxidation state= Oxidation number : ELECTRONS!!

Oxidation number= charge on ion!!! (sign first)

1.Neutral elements have oxidation of 0

Ex. H2, He, Fe

2.monoatomic ions

a.Ex. H+, Na+, K+, Li+---≥ lose one electron so oxidation is +1

b.F-, Cl-, Br-, I- ----> gain electron so oxidation is -1

3. H in molecule is +1

4.O in molecule is -2

5.Group 17:-1

6.Group 1: +1

7.Group 2: +2

Chapter 6

PV=nRT(memorize)

Pressure(atm) x volume( L)= mols of gas(mols) x gas constant (0.08206) x temperature (K) 1 atm= 760mmHg

Ex. If you fill a balloon with 5.00 grams of He gas at 298 K and 1.00 atm pressure, what's the V of the balloon?

PV=nRT

P= 1.00 atm

v=?

n= 5.00 g x 1mol/4.00 g= 1.25 mols

R= 0.08206

T= 298 K

1.00(V)= (1.25)(0.08206)(298)

V= 30.6 L

Collecting gas over water

Ptotal = Pgas( from reaction) + PH2O( evaporate)

Theory of Gas:

1. The size of a gas atom/ molecule is really tiny compared to the volume of gas 2. The average kinetic energy of atom/molecule depends on temp of gas 3. (KE=.5mv^2)(higher temp means higher velocity and higher KE)

4. Same temperature, different gas

a. KEgas1= KEgas2….

5. Same gas, different temperature

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