SEPARATION AGREEMENT


                  THIS  SEPARATION  AGREEMENT  (the  "Agreement")  is  made  and
entered into effective as of October 19, 2007 (the  "Separation  Date"),  by and
between Momentum Biofuels,  Inc., a Colorado corporation formerly known as Tonga
Capital Corporation (the "Company") and Stuart C. Cater (the "Executive").


                              W I T N E S S E T H:
                              --------------------

                  WHEREAS,  the  Executive  and the  Company are parties to that
certain  Executive  Employment  Agreement  dated  as  of  April  20,  2007  (the
"Employment Agreement"); and

                  WHEREAS,   the  parties  mutually  desire  to  arrange  for  a
separation  from the Company and its affiliates and  subsidiaries  under certain
terms; and

                  WHEREAS,  in  consideration  of the mutual promises  contained
herein,  the parties  hereto are willing to enter into this  Agreement  upon the
terms and conditions herein set forth.

                  NOW,  THEREFORE,  in consideration of the premises,  the terms
and  provisions  set  forth  herein,  the  mutual  benefits  to be gained by the
performance thereof and other good and valuable  consideration,  the receipt and
sufficiency  of which are  hereby  acknowledged,  the  parties  hereto  agree as
follows:

     1.  Termination  of Employment.  Effective as of the  Separation  Date, the
Executive  is  removed  from his  position  as Chief  Financial  Officer  of the
Company. The parties agree that the termination of the Executive's employment is
a  termination  for the  convenience  of the Company,  and is made without Cause
pursuant to the Employment Agreement.

     2.  Separation  Benefits.  The Company  agrees to pay or  provide,  and the
Executive  agrees  to  accept,  the  benefits  set  forth in this  Section  2 in
consideration  for the  Executive's  service through the Separation Date and the
additional consideration provided by the Executive pursuant to this Agreement.

          A. Payment of Severance.  The Company  agrees to pay the Executive the
     required  severance  payment agreed to in the  Employment  Agreement on the
     Separation  Date.  Payment  will  be  $60,000  due  upon  execution  of the
     Separation  Agreement with the remainder due in 12 monthly  installments of
     $7,500 due on the 15th of each month beginning November 15, 2007.

          B. Payment of Expenses.  Within 10 days following the Separation Date,
     the  Company  will pay to the  Executive  any  outstanding  expenses to the
     extent not already submitted, the Executive agrees to provide documentation
     in reasonable detail of any reimbursement request.



<PAGE>


          C.  Vesting of Option.  The parties  agree that the option to purchase
     2,000,000  shares of the Company's  common stock ("Common  Stock"),  as set
     forth on Exhibit A to the Employment Agreement (the "Option"), is currently
     exercisable with respect to 375,000 shares of Common Stock. The Option will
     remain  exercisable until April 20, 2012. The parties agree that a separate
     agreement  documenting  the  complete  terms of the Option will be executed
     contemporaneously  herewith in  substantially  the form attached  hereto as
     Attachment A.

          D. Removal of Lock-Up  Restrictions.  Effective  as of the  Separation
     Date,  the Company  agrees to waive the lock-up  restrictions  described in
     Exhibit A to the Employment Agreement with respect to any and all shares of
     Common Stock which the Executive has or may acquire in the future.

          E. Registration of Outstanding Shares. The Company agrees to cause all
     shares of Common Stock  currently held by the Executive to be registered on
     Form SB-2 along with the shares  sold in the  Company's  private  placement
     completed on September 4, 2007.

     3. Mutual Release of Claims.

          A. In consideration of the covenants from the Company to the Executive
     set  forth  herein,   the  receipt  and  sufficiency  of  which  is  hereby
     acknowledged,  Executive,  on his  behalf  and  on  behalf  of  his  heirs,
     devisees,   legatees,   executors,   administrators,   personal  and  legal
     representatives,  assigns and successors in interest,  hereby  IRREVOCABLY,
     UNCONDITIONALLY AND GENERALLY RELEASES, ACQUITS, AND FOREVER DISCHARGES, to
     the  fullest  extent  permitted  by law,  Company  and  each  of  Company's
     divisions,  subsidiaries,  successors and assigns,  agents, or any of them,
     from any and all charges,  complaints,  claims, damages, actions, causes of
     action,  suits, rights,  demands,  grievances,  costs,  losses,  debts, and
     expenses  (including  attorneys'  fees and costs  incurred),  of any nature
     whatsoever arising prior to the Separation Date;  provided,  however,  that
     nothing  contained  herein  shall  operate to release  any  obligations  of
     Company,  its successors or assigns (x) arising under any claims to amounts
     or benefits  described  in this  Agreement  or (y) to defend and  indemnify
     Executive to the maximum extent that directors and officers of corporations
     are  required  to be  indemnified  under  Colorado  law  or  the  Company's
     Certificate of Incorporation and Bylaws for all costs of litigation and any
     judgment or settlement amount paid.



<PAGE>





          B. In consideration of the covenants from the Executive to Company set
     forth herein, the receipt and sufficiency of which is hereby  acknowledged,
     the Company,  its assigns and successors in interest,  hereby  IRREVOCABLY,
     UNCONDITIONALLY AND GENERALLY RELEASES, ACQUITS, AND FOREVER DISCHARGES, to
     the fullest extent  permitted by law, the Executive,  his heirs,  devisees,
     legatees, executors, administrators, personal and legal representatives, or
     any of  them,  from  any  and all  charges,  complaints,  claims,  damages,
     actions,  causes of action,  suits,  rights,  demands,  grievances,  costs,
     losses, debts, and expenses (including attorneys' fees and costs incurred),
     of any nature whatsoever arising prior to the Separation Date.

     4.  Restrictive  Covenants.  The  Executive  acknowledges  that  all of the
remaining  covenants  set forth in  Section 7 of the  Employment  Agreement  are
operative  and remain in effect in  accordance  with their terms,  including the
Agreement contained in Section 7E.

     5. Mutual  Nondisparagement;  Press Release.  The Executive and the Company
and its  officers  and  directors  agree  to  refrain  from  any  criticisms  or
disparaging  comments,  orally or in  writing,  about  each  other or in any way
relating to the Executive's employment or separation from employment;  provided,
however,  that nothing in this  Agreement  shall apply to or restrict in any way
the communication of information by the Company or the Executive to any state or
federal law enforcement agency or require notice to the Company or the Executive
thereof,  and neither  the  Executive  nor the Company  will be in breach of the
covenant  contained  above solely by reason of  testimony  which is compelled by
process  of law.  The  parties  agree  that  any  press  release  regarding  the
Executive's  separation  will be reviewed and approved by both parties  prior to
distribution.

     6. Indemnification; D&O Insurance. The Company shall indemnify and hold the
Executive harmless against  judgments,  fines,  amounts paid in settlement,  and
reasonable  expenses  (including  attorneys  fees)  incurred by the Executive in
connection  with the defense of any action or  proceeding in which he is a party
by reason of his  position  as an  officer  or  director  of the  Company or any
affiliated  company or entity,  so long as the Executive acted in good faith and
in a manner the  Executive  reasonably  believed  to be in or not opposed to the
best  interests of the  Company,  and,  with  respect to any criminal  action or
proceeding,  Employee  had no  reasonable  cause  to  believe  his  conduct  was
unlawful;  provided,  however,  that such  indemnity  shall be  consistent  with
Colorado law and with the provisions  contained as of the date of this Agreement
within the Company's bylaws and charter,  or the affiliated  company or entity's
bylaws or charter, addressing the indemnification of its directors, officers and
authorized representatives for actions of the nature described herein. Until the
date 6 years  following  the  Separation  Date,  the Company  agrees to maintain
reasonable  directors and officers liability  insurance covering claims incurred
in respect of the period during which the Executive was a director or officer of
the Company.



<PAGE>





     7.  Nonassignability.  Neither  this  Agreement  nor any right or  interest
hereunder shall be subject,  in any manner, to anticipation,  alienation,  sale,
transfer,  assignment,  pledge,  encumbrance  or charge,  whether  voluntary  or
involuntary,  by  operation  of law or  otherwise,  any attempt at such shall be
void;  provided,  that any such  benefit  shall not in any way be subject to the
debts, contract,  liabilities,  engagements or torts of the Executive, nor shall
it be subject to attachment or legal process for or against the Executive.

     8. Entire  Agreement;  Modification.  This  Agreement sets forth the entire
agreement and understanding of the parties concerning the subject matter hereof,
and supersedes all prior agreements, arrangements and understandings relative to
that subject matter including,  without limitation, the Employment Agreement. No
term or provision hereof may be modified or  extinguished,  in whole or in part,
except by a writing which is dated and signed by the parties to this  Agreement.
No waiver of any of the  provisions or conditions of this Agreement or of any of
the rights,  powers or privileges of a party will be effective or binding unless
in writing and signed by the party  claimed to have given or  consented  to such
waiver. No representation, promise or inducement has been made to or relied upon
by or on behalf of either party  concerning  the subject  matter hereof which is
not set forth in this Agreement.

     9. Waiver.  No term or condition of this Agreement  shall be deemed to have
been waived,  nor there an estoppel  against the enforcement of any provision of
this  Agreement,  except by written  instrument  of the party  charged with such
waiver or estoppel.

     10. Notices.  All notices or communications  hereunder shall be in writing,
addressed as follows:

                           To the Company:

                           Momentum Biofuels, Inc.
                           Attn: Chairman of the Board
                           2600 S. Shore Blvd., Suite 100
                           League City, TX 77573

                           To the Executive:

                           Stuart C. Cater
                           14606 Decker Drive
                           Magnolia, TX  77355

All such  notices  shall be  conclusively  deemed  to be  received  and shall be
effective;  (i) if sent by hand delivery, upon receipt, (ii) if sent by telecopy
or facsimile  transmission,  upon  confirmation of receipt by the sender of such
transmission, or (iii) if sent by registered or certified mail, on the fifth day
after the day on which such notice is mailed.



<PAGE>





     11. Source of Payments.  All cash payments  provided in this Agreement will
be paid from the  general  funds of the  Company.  The  Executive's  status with
respect to amounts owed under this Agreement will be that of a general unsecured
creditor of the Company.

     12. Taxes. The Company may withhold from any benefits payable under this
Agreement all federal income or employment taxes that will be required  pursuant
to any law or governmental regulation or ruling. The Executive shall be entitled
to receive tax gross-up  payments,  to the extent required pursuant to the terms
of  Exhibit  A to the  Employment  Agreement,  which is  expressly  incorporated
herein.  Such payments,  if required,  will be made no later than the end of the
taxable year in which the Executive remits the underlying  taxes. This Agreement
is intended to comply with Section  409A of the Code (to the extent  applicable)
and the Company agrees to interpret,  apply and administer this Agreement in the
least restrictive  manner necessary to comply with such requirements and without
resulting  in any  diminution  in the  value  of  payments  or  benefits  to the
Executive.  For purposes of Section  409A of the Code,  the right to a series of
installment  payments  under  this  Agreement  shall be  treated as a right to a
series of separate  payments,  and the payments of severance  compensation  paid
under  Section  2 of  this  Agreement  shall  be  considered  payments  upon  an
involuntary  termination  under a  "separation  pay plan"  within the meaning of
Treas. Reg. Section 1.409A-1(b)(9)(iii).

     13. Severability. If any provision of this Agreement is held to be invalid,
illegal or unenforceable,  in whole or part, such invalidity will not affect any
otherwise valid  provision,  and all other valid  provisions will remain in full
force and effect.

     14.   Counterparts.   This  Agreement  may  be  executed  in  two  or  more
counterparts,  each of  which  will be  deemed  an  original,  and all of  which
together will constitute one document.

     15.  Titles.  The titles and headings  preceding the text of the paragraphs
and subparagraphs of this Agreement have been inserted solely for convenience of
reference and do not  constitute a part of this Agreement or affect its meaning,
interpretation or effect.

     16.  Governing  Law. This  Agreement  shall be governed by and construed in
accordance  with the laws of the State of Texas  (except that no effect shall be
given  to any  conflicts  of law  principles  thereof  that  would  require  the
application of the laws of another jurisdiction)

     17. Arbitration.  Any dispute or controversy arising under or in connection
with  this  Agreement  shall  be  settled   exclusively  by  final  and  binding
arbitration in Houston,  Texas,  in accordance  with the Employment  Arbitration
Rules of the American  Arbitration  Association ("AAA"). The arbitrator shall be
selected by mutual agreement of the parties, if possible. If the parties fail to
reach agreement upon  appointment of an arbitrator  within thirty days following
receipt by one party of the other  party's  notice of desire to  arbitrate,  the
arbitrator shall be selected from a panel or panels of persons  submitted by the
AAA.  The  selection  process  shall  be  that  which  is set  forth  in the AAA
Employment  Arbitration Rules then prevailing,  except that, if the parties fail
to select an arbitrator from one or more panels, AAA shall not have the power to
make an  appointment  but shall  continue to submit  additional  panels until an
arbitrator has been selected. This agreement to arbitrate shall not preclude the
parties from engaging in voluntary,  non-binding  settlement  efforts  including
mediation.



<PAGE>





     18.   Counterparts.   This  Agreement  may  be  executed  in  one  or  more
counterparts,  each of  which  shall be  deemed  an  original,  but all of which
together shall constitute one and the same instrument.



                                  [END OF PAGE]



<PAGE>



                  IN WITNESS  WHEREOF,  the parties have executed this Agreement
on  __________________,  2007, but effective as of the date and year first above
written.


                                     MOMENTUM BIOFUELS, INC.



                                     By:______________________________
                                     [Name]
                                     [Title]


                                     EXECUTIVE


                                     _________________________________
                                     Stuart C. Cater

























<PAGE>









                                  ATTACHMENT A

                             MOMENTUM BIOFUELS, INC.
                   AMENDED AND RESTATED OPTION AWARD AGREEMENT

                  This award  agreement (the  "Agreement") is entered into as of
October 19, 2007, by and between  Momentum  Biofuels,  Inc.,  formerly  known as
Tonga Capital Corporation (the "Company"), and Stuart C. Cater (the "Optionee").
This Agreement  amends and restates,  and supersedes and replaces,  the terms of
the option awarded as of April 20, 2007, pursuant to Exhibit A to the Employment
Agreement by and among the Company and Optionee.

                  Grant;  Exercise  Price:  The Company  has granted  Optionee a
right (the "Option") to purchase from the Company up to 375,000 shares of common
stock of the Company ("Common Stock") at $1.00 per share (the "Exercise Price"),
which is not less than the fair  market  value of a share of common  stock as of
the grant date.  The number of shares of Common Stock  subject to the Option and
the Exercise Price are subject to adjustment as provided in Section 7.

                  Vesting and Exercise of Option: This Option is fully vested
and exercisable as of October 17, 2007.

                  Termination  of  Option:   Notwithstanding  anything  in  this
Agreement  to the  contrary,  this Option shall  terminate  and be of no further
force and effect on April 20, 2012.

                  Notice of  Exercise  and  Payment:  Once the Option has become
exercisable,  the Optionee may purchase  shares of Common Stock pursuant to this
Agreement by (i) giving written notice to the Company of the number of shares of
Common Stock which are to be purchased provided that such number does not exceed
the number of shares of Common  Stock which the Optionee is entitled to purchase
at such time pursuant to this Agreement and (ii) delivering a cashier's check or
money  order  or,  at the  option  of  the  Optionee,  shares  of  Common  Stock
theretofore  owned by such Optionee for at least six months (or any  combination
of cashier's check, money order or such Common Stock), in an amount equal to the
Exercise  Price  multiplied by the number of shares of Common Stock which are to
be purchased.  For purposes of determining  the amount,  if any, of the Exercise
Price satisfied by payment in Common Stock, such Common Stock shall be valued at
its fair market  value on the date of exercise.  Any Common  Stock  delivered in
satisfaction  of all or a portion of the purchase  price shall be  appropriately
endorsed for transfer and  assignment  to the Company.  If the Company  adopts a
broker-assisted  cashless  exercise  program  for  options  issued to  executive
officers,  the Company  agrees to make such program  available to Optionee  with
respect to the Option.



<PAGE>





                  Delivery  of  Common  Stock  by  the   Company:   As  soon  as
practicable  after receipt of all items referred to in Section 4, and subject to
the withholding  referred to in Section 8, the Company shall deliver to Optionee
certificates  issued in Optionee's name for the number of shares of Common Stock
purchased by exercise of the Option. If delivery is by mail,  delivery of shares
of Common Stock shall be deemed  effected for all purposes when the Company or a
stock transfer agent of the Company shall have deposited the certificates in the
United States mail, addressed to Optionee.  The Optionee shall have no rights of
a  shareholder  with  respect  to shares of Common  Stock  subject to the Option
unless and until such time as the Option has been  exercised  and  ownership  of
such shares of Common Stock has been transferred to the Optionee

                  Assignability:  The Option granted under this Agreement  shall
not  be  sold,  transferred,   pledged,   assigned  or  otherwise  alienated  or
hypothecated  by the  Optionee,  and during the  lifetime of the  Optionee,  the
Option shall be exercisable  only by him, or, if the Optionee  becomes  mentally
incapacitated,  the  Option  shall  be  exercisable  by his  guardian  or  legal
representative.  Any  attempted  assignment  or  transfer in  violation  of this
Section  shall be null  and  void.  Upon  the  Optionee's  death,  the  personal
representative or other person entitled to succeed to the rights of the Optionee
(the "Successor  Optionee") may exercise such rights. A Successor  Optionee must
furnish  proof  satisfactory  to the Company of his or her right to exercise the
Option under the  Optionee's  will or under the  applicable  laws of descent and
distribution.

                  Adjustments:

                  The  existence  of this Option  shall not affect in any manner
         the  right or  power  of the  Company  or its  shareholders  to make or
         authorize any or all adjustments, recapitalization,  reorganizations or
         other  changes in the  ownership  of the Company or its business or any
         merger  or  consolidation  of the  Company,  or  any  issue  of  bonds,
         debentures, or other obligations,  or the dissolution or liquidation of
         the  Company,  or any sale or transfer of all or any part of its assets
         or business,  or any other  corporate  act or  proceeding  of any kind,
         whether  or  not  of a  character  similar  to  that  of  the  acts  or
         proceedings enumerated above.

                  In  the   event   of  any   stock   distribution   or   split,
         recapitalization,   extraordinary  dividend,   merger,   consolidation,
         combination  or  exchange  of shares  or  similar  change,  or upon the
         occurrence of any other  similar event that the Board of Directors,  in
         its sole discretion, deems appropriate, the (i) the number of shares of
         Common Stock  purchasable  under this Option,  (ii) the Exercise Price,
         and (iii) any other  determinations  shall be  adjusted as the Board of
         Directors deems appropriate; provided, however, that (i) the parties to
         this Agreement  intend that any such  adjustment  shall only be made to
         the  extent  that it will not  result in  accelerated  taxation  or the
         imposition of an excise tax under Section 409A of the Internal  Revenue
         Code of 1986,  as  amended,  and the  relevant  regulations  and  other
         guidance that may be issued  thereunder and (ii) such adjustments shall
         be designed to preserve, without increasing or decreasing, the value of
         the  Option and shall be  consistent  with the  treatment  of shares of
         Common Stock not subject to this Option.



<PAGE>





                  Withholding:  The Company may require the Optionee to remit to
the Company an amount  sufficient  to satisfy  federal,  state,  local and other
withholding tax requirements,  as a condition to the purchase by the Optionee of
shares of Common Stock pursuant to this  Agreement.  The Optionee may pay all or
any  portion of the taxes  required to be withheld by the Company or paid by the
Optionee in connection with the exercise of all or any portion of this Option by
delivering  cash, or by electing to have the Company  withhold  shares of Common
Stock, or by delivering  previously owned shares of Common Stock,  having a fair
market value equal to the amount required to be withheld or paid.

                  Securities   Law   Restrictions:   The   Company   shall   use
commercially  reasonable  efforts to register the shares of Common Stock subject
to the  Option  pursuant  to the  Securities  Act of 1933 on Form S-8 or on such
other form as may be  available.  Until the  Option  and shares of Common  Stock
covered by this Agreement have been registered under the Securities Act of 1933,
as amended, the Optionee may be required by the Company to give a representation
in writing in form and substance  satisfactory to the Company to the effect that
he is acquiring  such shares of Common Stock for his own account for  investment
and not with a view to, or for sale in connection with, the distribution of such
shares of Common Stock or any part thereof.

                  Notices:  Notice or other communication to the Company with
respect to this Option,  including  the  notice  of  exercise,  must be made  by
registered  or certified United States mail,  postage prepaid or by hand
delivery or otherwise, to Momentum  Biofuels,  Inc., Attn:  Chairman of the
Board, 2600 S. Shore Blvd., Suite 100, League City, TX 77573, Attention:
Chairman of the Board.

                  Notwithstanding  the foregoing,  in the event that the address
of the Company is changed, any such notice shall instead be made pursuant to the
foregoing provisions at the Company's current address.

                  Any notices  provided for in this Agreement  shall be given in
writing and shall be deemed  effectively  delivered or given upon receipt or, in
the case of notices  delivered by the Company to the  Optionee,  five days after
deposit in the United States mail, postage prepaid, addressed to the Optionee at
the address  specified at the end of this  Agreement or at such other address as
the Optionee hereafter designates by written notice to the Company.

                  Governing  Law:  This  Agreement  shall  be  governed  by  and
construed  in  accordance  with the laws of the State of Texas  (except  that no
effect  shall be given to any  conflicts  of law  principles  thereof that would
require the application of the laws of another jurisdiction).

                  Arbitration:  In the  event  of  any  dispute,  difference  or
question  arising  between  the Company and  Optionee  in  connection  with this
Agreement  shall be governed by the dispute  resolution  procedures  outlined in
Section 17 of the Separation Agreement between the Company and Optionee dated as
of October 19, 2007.



<PAGE>





                  Entire Agreement:  Optionee and the Company hereby declare and
represent  that no promise or agreement  not herein  expressed has been made and
that this  Agreement  contains the entire  agreement  between the parties hereto
with  respect  to the  Option  and  replaces  and makes  null and void any prior
agreements,  oral or written,  between  Optionee and the Company  regarding  the
Option.

                  Right of First Refusal:  Optionee  hereby grants the Company a
Right of First  Refusal to purchase the Option,  or shares  purchased  under the
Option,  which he plans to sell, upon ten days written notice,  with such Notice
specifying  such  other  bona fide  offer  price and  terms,  or if such sale is
proposed at market price, then the Company may purchase such shares or Option by
cash tender within ten days after date of notice. If the Option is being sold by
Optionee,  under  terms  other than cash,  the  Company  shall have the right to
purchase on the same terms. Such Right of First Refusal shall extend for 5 years
from date hereof, and may not be modified except in writing.

                  Counterparts:  This Agreement may be executed in one or more
counterparts, each of which shall be deemed an original, but all of which
together shall constitute one and the same instrument.

                            [Signature Page Follows]



<PAGE>



                  IN WITNESS  THEREOF,  the parties  hereto have  executed  this
Agreement as of the day first above written.

                                                     MOMENTUM BIOFUELS, INC.



                                                     By:
                                                                    Name:
                                                                    Title:

                                                     OPTIONEE



                                                     Stuart C. Cater
                                                     14606 Decker Drive
                                                     Magnolia, TX 77355