The size of the granules differ depending on what kind of sugar you are talking about. www.joyofbaking.com/sugar.html
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
about 10-12 thousand in the average male adults hand
It depends, the brand of the sugar, the sand is from where, normally sugar is bigger than sand
The floor was sprinkled with scratchy granules of sugar.
a large U.S. state
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.
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.
Grains of sugar vary in size depending on the time taken for formation. The longer it takes to form the granule the larger the granule of sugar. Castor sugar is small (<1.0 mm) whereas Demerara sugar is quite large ~ 2mm. Icing sugar is a powder.