The phrase "an unexpected amount" is correct and usable in written English.
It can be used when referring to a quantity or degree that is surprising or not anticipated.
Example: "The project received an unexpected amount of funding, allowing us to expand our research efforts."
Alternatives: "a surprising quantity" or "an unforeseen extent".
1 Mr. Bush is now spending an unexpected amount of time and money campaigning in Florida.
Excavations since the mid-20th century have revealed an unexpected amount of open land.
Now, I expended an unexpected amount of energy ragging on a Middleton in this column last week and I have no desire to develop a habit of it.
What's interesting is the way he not only mines big laughs from this, but also an unexpected amount of gentle pathos.
There has been an unexpected amount of attention lavished on a man who had pledged to live out his days "hidden from the world".
In southern New Jersey, where an unexpected amount of rain has fallen, the weather has delayed construction of everything from houses to the new arcade at Fantasy Island Amusement Park, in Long Beach.
Jamal Khan*, 22, left teaching after completing a graduate training scheme because the unexpected amount of admin and bureaucracy, and pupil apathy, meant he couldn't meet the standards he set for himself.
In the vacuum gas oil cut, which contains mostly four aromatic rings, we found 11 wt% of asphaltenes (compounds in n-heptane), an unexpected high amount comparing to petroleum VGO fractions.
The recent demonstration of an unexpected high amount of freely accessible, non-proteinaceous copper within the mitochondrial matrix of S. cerevisiae and mice [8], [9], [76], [77] makes it very likely that mitochondria also serve as a copper reservoir in plants.
Although plasmalogen levels in patient fibroblasts were in accordance with their rate of biosynthesis, there was an unexpected residual amount of PlsEtn in fibroblasts of the severely affected group.
"To behold the unexpected amount of Spurs fans in the stands of the SBC Center, wearing black-and-white shirts with the No. 20, seems like a dream," the columnist Miguel Romano wrote in the daily La Nación the same day.
