Heat oven to 375 degrees with oven rack at lowest level.
Remove giblets from chicken and discard. Rinse chicken inside and out. Pat dry with paper towels. Place chicken in large roasting pan, 12″ x 18″.
In a large mixing bowl, whisk together the lemon juice, olive oil, rosemary, oregano, garlic powder and black pepper. Set aside.
Rinse baby carrots. Wash celery and cut into 2 inch chunks. Wash yellow potatoes and slice in half lengthwise (No need to peel! Love those yellow spuds!) Clean onion and cut into 1″ chunks. Place veggies in lemon marinade and toss to coat.
Arrange veggies around the chicken. Baste chicken with remaining marinade.
Bake at 375 for 90 minutes, turning veggies halfway through. Test chicken with meat thermometer at thickest part. Temperature should be 180 degrees for well done.