“Star cluster” is a generic way for astronomers to refer to a group of stars that formed from the same material and are gravitationally bound for at least some period of time. There are two major types of star clusters — globular clusters and open clusters — and they are actually quite different.
Answer:
stirring
Explanation:
when you stir it spreads the item out more to be fully covered and dissolve faster. like putting sugar in tea, if you don' t stir it wont dissolve fast
Answer:
Element: H (hydrogen)
Compound: H2O (water)
Explanation: An element is made up of a singular atom while a compound is made up of 2 or more
Answer:
group two elements are called alkaline earth metals
Explanation:
Because their oxides form in the earth and are water soluble
Number of moles is defined as the ratio of given mass in g to the molar mass.
The mathematical formula is:
Number of moles = 
(1)
Number of zinc atoms is equal to 
, by Avogadro number, number of moles can be calculated.
As, 1 mol=
atoms, hence,
= 0.2822 mol
Now, from formula (1), calculate mass in g (molar mass of zinc = 65.4 g/mol)
0.2822 mol = 
mass in g = 
= 18.45588 g
Thus, by rounding off the above number, it will come near about 19 g approximately.
Hence, option (C) is the correct answer.
