Answer:
A) All the elements are composed of atoms.
d) Atoms cannot be created or destroyed in any chemical changes.
c) An atom of one element cannot be changed into an atom of a different element.
Explanation:
The main postulates of Dalton atomic theory was:
1) The matter is composed of atoms and atom is indivisible particle which can not be destroyed.
2) The atoms of an element are identical.
3) The atoms of different elements are combining with definite proportion and form compounds.
4) The atoms of different elements are different from each other.
5) During chemical reaction rearrangement of atoms occur and form new compounds.
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Answer:
Explanation:If 5.51 g of water needs 645 J of energy to warm then 55.1 g of water needs 6450 J of energy to warm.
Answer:
The human cheek cell is a good example of a typical animal cell. It has a prominent nucleus and a flexible cell membrane which gives the cell its irregular, soft-looking shape.
Answer:
14 ml of water
Explanation:
To find the volume you need to dilute the concentration of a solution, you should use the formula C1 x V1 = C2 x V2 in which:
C1 = initial concentration ( in this case 60 %)
V1 = initial volume ( in this case 70 ml)
C2 = Final concentration ( you want to dilute until 50 %)
V2 = final volume ( the variable you want to search)
So you need to:
1.- Isolate the variable you want to find: V2 = (C1 x V1) / C2
2.- Substitute data: V2 = (60% x 70 ml) /50 %
3.- You do the math, in this case is 84 ml.
4.- Remember that you have a initial volume of 70 ml, so the difference (84 ml - 70 ml = 14 ml) is the volume you need to add to dilute your solution.
