SEPARATION AGREEMENT


                  THIS  SEPARATION  AGREEMENT  (the  "Agreement")  is  made  and
entered into effective as of October 16, 2007 (the  "Separation  Date"),  by and
between Momentum Biofuels,  Inc., a Colorado corporation formerly known as Tonga
Capital Corporation (the "Company") and Barent W. 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  15,  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 President and Chief Executive  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 Expenses.  Within 5 days following the Separation  Date,
     the  Company  will pay to the  Executive  $72,095.49,  which  includes  (1)
     $57,095.49  ($55,923.40  Principal,  $1,172.09 interest),  in settlement of
     that  certain  promissory  note  executed  on July 19, 2007 in favor of the
     Executive,  and (2) $15,000 in reimbursement of attorneys' fees paid by the
     Executive in  connection  with the  preparation  of his initial  employment
     agreement.



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          B.  Vesting of Option.  The parties  agree that the option to purchase
     5,000,000  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 1,000,000  shares of Common  Stock.  As of the
     Separation Date, the Company agrees that the Option will become exercisable
     with respect to an additional 500,000 shares of Common Stock, such that the
     Option will be exercisable  with respect to a total of 1,500,000  shares of
     Common Stock. The Option will remain  exercisable until April 15, 2012. The
     parties  agree  that  a  separate  agreement  amending  and  restating  and
     documenting   the   complete   terms  of  the  Option   will  be   executed
     contemporaneously  herewith in  substantially  the form attached  hereto as
     Attachment A.

          C. 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.

          D. 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.



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          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 Company agrees that the covenants set forth
in Section 7.E. of the  Employment  Agreement  are no longer  applicable  and to
waive any claim it may have in the future to enforce such section. The Executive
acknowledges  that  the  remaining  covenants  set  forth  in  Section  7 of the
Employment Agreement are operative and remain in effect in accordance with their
terms.

     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.



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     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 shall there be 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:

                           Barent W. Cater
                           13 Mariners Lane
                           Kemah, Texas  77565

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.



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     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  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.

     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.

     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.



                            [Signature Page Follows]



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                  IN WITNESS  WHEREOF,  the parties have executed this Agreement
on the date and year first above written.


                                    MOMENTUM BIOFUELS, INC.



                                    By:________________________
                                       Name:
                                       Title:


                                    EXECUTIVE


                                    ____________________________
                                    Barent W. Cater




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                                  ATTACHMENT A

                  FORM OF AMENDED AND RESTATED OPTION AGREEMENT