Elegant Themes does a great job of making beautiful themes using the widely accepted "Golden Ration" in their layouts. In the Chameleon theme this rule is applied to the amount of space given to the content and sidebar - roughly two-thirds for content and one-third for the sidebar. If you're a rule breaker and hate to see all that wasted space on the sidebar, this tweak will borrow that space and allot it to the content area. There are a lot of moving parts in this tweak. If things don't quite line up, it's likely due to another plugin, especially any sidebar widget plugins.  You may have to play around with the numbers in the code below but it will work on stock Chameleon. 

CSS

Locate your style.css file in /chameleon-child/

Add this code:

#content {
padding: 0 0 60px 30px;
background-position: 735px;
}

#left-area {
width: 700px;
padding-left: 5px;
}

.post {padding: 35px 0 25px 0;}

.post p {padding-right: 20px;}

.post a.read-more {margin-right: 20px;}

#sidebar {
width: 222px;
float: left;
padding-top: 35px;
padding-left: 0;
}

.widget {
width: 170px;
padding-left: 30px;
padding-right: 0;
}

Because this opens up so much more room for your content, you could also justify the text to make for a more appealing layout. If you do this, you'll want to add a little extra padding to the right side so it matches the left. Change the ".post p" in the code above to this to justify your text and add the padding:

.post p {
padding-right: 30px;
text-align: justify;
}