Newcastle increased West Brom's relegation worries with a comfortable victory at St James' Park.
Once Ameobi made it 2-0, Newcastle were never in danger
The home side dominated the first half but Nolberto Solano's tap-in and Shola Ameobi's penalty were all they had to show for the one-way traffic.
Three half-time changes gave West Brom more solidity but they still posed little threat up front.
Nathan Ellington wasted West Brom's best chance with a weak off-target shot before Ameobi's second sealed the win.
After a sluggish start by both sides, Newcastle served notice of what was to come when Solano rattled the bar from 30 yards, with the impressive Matty Pattison putting his follow-up wide.
Amdy Faye should have done better following Jonathan Greening's blunder, but eventually Newcastle took a deserved lead when Chopra's shot was deflected into path of Solano, who stabbed home from close range.
Neil Clement was lucky to stay on when he pushed over Chopra, having already been booked, but Ameobi gained justice, converting the penalty.
West Brom changed their forward pairing at the interval, replacing Diomansy Kamara and Kevin Campbell with Kanu and Nathan Ellington, but without much obvious result.
The one-sided nature of the match meant much of the second half was played out in a subdued atmosphere.
Charles N'Zogbia and Chopra both had chances to add to Newcastle's advantage as the home side dominated without too much effort.
When West Brom finally managed a threat on goal, Ellington's shot from the edge of the box dribbled tamely wide, and with it disappeared any vague threat of a comeback.
Ameobi rounded things off, running through to fire home to clinch Newcastle's fifth successive Premiership win.
Newcastle caretaker boss Glenn Roeder:
"Shola has had criticism in the past which he does not deserve and he is keen to show the fans what he is capable of.
"I have faith in him and have started with him every time he has been fit. He scored two goals in this game and his overall play was excellent.
"Shola and Michael Chopra look like they are a good striking partnership."
West Brom manager Bryan Robson:
"If I could have made 11 changes I would have. Until I made the changes at half-time we didn't compete.
"We looked at times as if we looked sorry for ourselves. Mathematically we can still stay up but we are relying big style on Birmingham and Portsmouth.
"We also have to win our last two games which we don't look like doing."
Newcastle: Given, Carr, Moore, Bramble, Babayaro, Solano, Faye, Pattison (Clark 80), N'Zogbia, Ameobi, Chopra.
Subs Not Used: Harper, Elliott, Boumsong, Luque.
Goals: Solano 30, Ameobi 40 pen, 90.
West Brom: Kuszczak, Albrechtsen, Curtis Davies, Clement, Robinson, Gera, Watson (Inamoto 45), Quashie, Greening, Campbell (Kanu 45), Kamara (Ellington 45).
Subs Not Used: Hoult, Carter.
Ref: H Webb (S Yorkshire).