US STOCKS-China data helps Wall St gain for fifth straight day

* China exports top expectations

* Jacobs Engineering (NYSE: JEC - news) to buy Sinclair Knight

* Koch Industries to buy Molex for about $7.2 billion

* Indexes up: Dow 0.67 pct, S&P 0.62 pct, Nasdaq 0.71 pct

By Chuck Mikolajczak

NEW YORK, Sept 9 (Reuters) - U.S. stocks rose on Monday, helping the S&P to advance for a fifth straight day following upbeat economic data from China, though concerns about the possibility of a Western strike against Syria tempered investor enthusiasm.

China, the world's second-biggest economy, reported its exports had grown by 7.2 percent in August, beating market expectations for a 6 percent increase, while consumer inflation held steady in August.

The benchmark index has gained 1.9 percent over the past five days, but analysts said numerous events, from Syria to a possible trimming of stimulus by the Federal Reserve and the debt ceiling debate, could easily create volatility.

"There are so many things out there that could upset the apple cart right now," said Peter Jankovskis, co-chief investment officer at OakBrook Investments LLC in Lisle, Illinois.

"It is hard to forecast how this Syria vote is going to go," Jankovskis said. "The Fed, some of the recent data, particularly the jobs data, is causing people to revise their expectations for when tapering is going to start, certainly taking some of the urgency off there."

Syrian President Bashar al-Assad denied he was behind a chemical weapons attack on Syrian civilians, as the White House pressed ahead Sunday with the uphill effort of persuading Congress to approve a military strike to punish Assad. The Obama administration faces a test vote Wednesday in the U.S. Senate.

Assad has warned against possible reprisal attacks if the U.S. attacks Syria, saying that in response, Americans can "expect every action."

The S&P 500 is up 16.7 percent for the year, largely driven by the $85-billion monthly bond purchases of the Fed, aimed at stimulating the economy.

Economists at a majority of U.S. primary dealers expect the Fed to announce, at a two-day policy meeting next week, that it will start to pare back its bond purchases soon, according to a Reuters poll.

The Dow Jones industrial average rose 100.28 points or 0.67 percent, to 15,022.78, the S&P 500 gained 10.23 points or 0.62 percent, to 1,665.4 and the Nasdaq Composite added 26.119 points or 0.71 percent, to 3,686.129.

Molex Inc shares surged 31.4 percent to $38.56 as the best performer on the S&P 500 after the maker of electronic, electrical and fiber optic interconnection systems, said privately owned Koch Industries will buy it for about $7.2 billion. The S&P technology index rose 0.8 percent.

Jacobs Engineering Group Inc, one of the world's largest construction consulting firms, said Sunday it would buy Australia's Sinclair Knight Merz for about A$1.3 billion ($1.2 billion) in cash. Jacobs shares rose 1.3 percent to $58.82.

U.S.-listed shares of BlackBerry Ltd gained 2.5 percent to $11.11after the Sunday Times reported that the company's largest shareholder, Prem Watsa, had assembled billions of dollars in backing from Canada's biggest pension funds for a possible rescue deal for the battered smartphone maker.

Isis Pharmaceuticals Inc (Stuttgart: 881866 - news) jumped 11.5 percent to $31.12 after the company said it had reached a collaboration with Biogen Idec Inc (NasdaqGS: BIIB - news) on treatments for neurological disorders. Biogen shares edged up 0.3 percent to $225.77.

Delta Air Lines Inc (NYSE: DAL - news) will join the S&P 500 index after the close of trading Sept. 10, replacing BMC Software (NasdaqGS: BMC - news) . Delta shares surged 6.1 percent to $21.10.