More lighthearted discussion amongst the current chaos

Just some questions for the group on US coinage…

Why does the US mint most gold coins in 22k vs 24k? But then they have the Liberty series 24k?

Why do the proof silver quarters weigh only 0.199 ozT…why not 0.25 ozT like the name “quarter implies”?

Same with the dime at 0.079 ozT and half dollar at 0.399 ozT?

Curious as to why the silver weight is not on par with the value relative to the dollar.