density of glucose

pwd

Two sources say it is 1.4 and 1.6 respectively.
I opened a 500g bag of glucose and measured its volume as 875ml, which would indicate it is .57.
When I compared the weight of similar volumes of glucose and water, the water was heavier.
Is glucose syrup a different form of the same substance, or is it just glucose mixed with water.
What is the desnsity of glucose? Why are my figures so different?

Professor_Fink

The density depends on a number of factors. If the glucose you have is powdered, then it will contain a lot of air, which will substantially lower the density. The density is also temperature and to a lesser extent pressure dependant. Is it possible that the two sources you have are for different temperatures or different forms of glucose?

pwd

That's what i was wondering when I asked if glucose syrup was the same substance in a different form. (It isn't; it is a glucose suspension.)
It is powdered glucose so I think your explanation about it containing air is the most likely explanation for my measurement being so much lower. The other two figures may have been different temperatures also.
Thanks Professor

Capt'n Midnight

Because it's a powder it would have air in it
Because it dissolves in water you can't measure the volume that way.
When you add it to water it sinks so the density is above 1g/cc

You could try to measure the volume of a known weight with oil

Also glucose has water in it's crystals. IIRC for sucrose it's 6 molecules of water per sucrose molecule.

Linear expansion coefficients for soilds are usually lower for solids than liquids so I'd ignore that effect, unless you have some serious kit.

Another option would be to grow a very large glucose crystal so there is no air entrapped and get it's density, might not take as long as you think if you seed properly. Water can dissolve up to three point six times it's weight of sucrose under ideal conditions but far less at room temperature so Glucose should be similar.

Retr0gamer

the only real way of doing it is to get the powdered glucose is liquid form and measure the weight per unit volume. Getting the density of a solution is worthless since it is then the density of a mixture of water and glucose.

The problem is that the liquid expands at high temperatures (although probably not that much). Glucose wil need a fairly high temperature befor it melts and it might even react with oxygen and burn before it melts. A solution could be to melt the glucose at low pressures since it will form a liquid at lower temperatures under low pressure.

I don't really see why you need to know the density since a quantity of glucose can just as easily explained with moles or weight.