That's less than one unit of surface area to service each unit of volume.

为每个体积单位提供服务的表面积不到一个单位。

This would give us six units of surface area for every single unit of volume, a six to one ratio.

这将为我们提供每单位体积六个单位的表面积，比例为六比一。

In salt water, the dissolved salt ions fill the unused space between water molecules, which means there is more mass in a given unit of volume of salt water compared to fresh water.

在盐水中，溶解的盐离子填充水分子之间未使用的空间，这意味着与淡水相比，给定单位体积的盐水的质量更大。