The size of the granules differ depending on what kind of sugar you are talking about. www.joyofbaking.com/sugar.html
It depends, the brand of the sugar, the sand is from where, normally sugar is bigger than sand
Each sugar granule has the mass (space) the granule occupies. Collectively, when in a 2kg bag of sugar, the mass is more obvious. Obviously, it would be difficult to measure a single granule (but not impossible).
The size of a typical granule seen in the photosphere is about 1000 km across.
Texas
The floor was sprinkled with scratchy granules of sugar.
A typical solar granule is about the size of a small state, such as Texas, on Earth. They are roughly 1000 kilometers in diameter and form the visible surface of the Sun.
Powdered sugar is made up of smaller granules than regular granulated sugar. That means that there is more air in a cup of powdered sugar than there is in a cup of granulated sugar because for each granule to remain separate there has to be space or air around each granule.
The size of the salt granule.
It depends on how much granulated sugar you have. Also, sugar granules come in different sizes so you cannot measure the mass of a single granule.
Specialty stores or online, or you can make your own by using granulated sugar in your food processor. Be sure to pulse so the sugar does not melt from built up heat.
Those are two different things. Mass of a sugar packet . . . gram might be best. Capacity or volume of a sugar packet . . . cubic centimeter might be best.
Bulk white sugar weighs 880 kilograms/cubic meter. Bulk table salt weighs 1154 kilograms/cubic meter. So no, salt and sugar don't have the same mass. Further They do not have the same density. 1 kilo of sugar has the same mass as 1 kilo of salt.