Changing Font weight between h1 and h2

Currently the CSS in my theme is:

h1, h2, h3 {
	font-family: Sans-Serif ;
        font-weight:normal
	}

h1 {
        font-size: 5em;
	text-align: left;
	padding-left:40px;
	}

#headerimg .description {
	font-size: 1.6em;
	padding-left:40px;
	}

h2 {
	font-size: 2.2em;
        clear:both;
	}	

h2.pagetitle {
	font-size: 2.2em;
	font-style: italic;
	}	

#sidebar ul li h2 {
	font-family: Georgia, Arial, 'Lucida Grande', Verdana, Sans-Serif;
	font-size: 1.6em;
	padding: 5px 5px;
	}

I would like “h1” to be bold and “h2” to be normal. How do I go about that? Thanks for the help in advance. I am new to CSS.

Michael