Yes.
Grapes, as a fruit, are kosher. However, grape products have additional rules specific to grapes due to the religious significance of the fruit.
Kosher turkey comes in both fresh and frozen.
At the kosher butcher or grocery store.
There are several stores that carry Empire Kosher fresh turkey. One store that carries the turkeys is Wegmans.
All water is kosher, there's no such thing as 'special kosher water'. A mikvah is simply required to have fresh running water from a natural resource.
Sabeny.com is a new kosher online grocery store. They sell a range of Kosher groceries and meat and have a price guarantee. They currently sell fresh and frozen kosher meat and kosher poultry, in addition to all other kosher grocery products.
2.5 kg 20 kg fresh grapes will contain 2 kg of grapes and 18 kg water. In dried grape, grape concentration is 80%; that implies 2kg should be taken as 80%. So, total weight of dried grape is 2.5kg.
Yes, there are no restrictions on fruit for Passover.
Fresh water chestnuts are fine. Canned water chestnuts require a kosher for Passover hechsher.
grapes
Kosher preparation. The main consideration in kosher food is that all the ingredients must be kosher, and the machinery that the food is processed on should not have been used to make non-kosher foods. Wine is different than food because of a sensitive historical situation. Because idolators used to offer wine to their idols, kosher wine must be protected under the supervision of a religious Jew or certifying agency. Today, the way you can be sure that wine or processed foods are kosher is that they have the symbol of a kosher certifying agency.
Fresh grapes do not significantly increase in sweetness if left out at room temperature. While they may become slightly softer and lose some moisture, which can concentrate their sugars, the overall sugar content remains relatively stable. For optimal sweetness, grapes are best enjoyed fresh and chilled.