Question...can you lift more with barbells vs dumbells?

This is a silly question, and one that plays to my vanity...but I'm wondering if it's easier to lift more with a barbell than it is to lift with a dumbbell? It's ridiculous, really, I'm comparing myself...but I generally lift 18lbs/hand (36 total weight) for squats with my dumbbells, and that feels difficult! My sister will lift 65 pounds total for squats with her barbell. I've never tried a barbell, but I'm totally impressed by her ability to lift that! And, a little jealous, haha! But, I am curious is the weight distribution changes anything? Does anybody know?