Why is there a gap between image and navigation bar - html

Question

Hi I'm having some trouble removing a small gap between an image and my navigation bar. I've honestly tried just about everything i can think of. Setting inline-blocks on my ul and li level, and using text-align: left don't seem to be moving the hyperlinks to the left-most side of the div, and from there I'm not to sure what should be done. There is a padding, but it shouldn't be causing that much of a gap.
Here is the html code:
<div id = "header">
<img src ="img.png"/>
<div id ="nav_bar">
<ul class="nav">
<li class= "nav">Home</li>
<li class= "nav">Our Products</li>
<li class= "nav">Categories</li>
<li class= "nav">About Us</li>
<li class= "nav">Contact Us</li>
</ul>
</div>
</div>
Here's a jfiddle describing what I'm talking about.
http://jsfiddle.net/37VZb/1/
To clarify the gap I'm talking about is between the right of the image and the left most nav bar element.

Answer 1

That's because of a space character between inline(-block) elements. This could be fixed by commenting that space out this way:
<img src ="http://www.leapcms.com/images/100pixels1.gif"/><!--
--><div id ="nav_bar"> ...
JSFiddle Demo.
Similar topic on SO:
How to remove the space between inline-block elements?
And a good reference:
http://css-tricks.com/fighting-the-space-between-inline-block-elements/
Update
The remaining space belongs to the user agent applied style on the <ul> element.
Web browsers usually apply some padding on the list elements. To remove that set padding: 0; as follows:
ul.nav { padding : 0; }
Here is the Updated Fiddle.

Answer 2

is this what you mean? You can target the nav class on your ul and adjust the default margins that are being assigned
ul.nav{
margin: 10px 0;
}
JSFIDDLE

Answer 3

Your gap is a white space like you find in between words since both element are set as inline boxes. In your CSS you set as well somme padding to ul and a , they both are there.
http://jsfiddle.net/37VZb/8/
.nav_bar, .nav{
padding:0;
display:inline-block;
}
To get rid of it:
1) do not indent your code and get closing and opening brackets of element touch each other
2) add a CSScomment in between to swallow that white-space
3) set font-size to 0 (0.01px for IE) to parent of these inline-boxes and reset it ot back to 1rem (and or px/pt) for img (alt) and nav_bar
negative margin or negative letter-spacing are not to be used, it is not reliable and not meant to care about this