Quad-core Vs. Dual-core processor

So, I'm buying a new computer for school. The supply list I have recommends a 7th gen MacBook with a dual-core processor, but Apple.com only has 8th gen MacBooks with quad-core processors. And I have looked elsewhere, but I can't find one that fits the exact perimeters.

So my question: is an 8th gen with a 1.4 GHz quad-core processor better than, equal to, or worse than a 7th gen with a 2.3 GHz dual-core processor (that the school recommended)?

I've yet to hear back from my teachers about my query; Anyone know?