E=hf
h=6.63*10^-34
f=8.66*10^14
E=6.63*10^-34*8.66*10^14=57.4*10^-20 joules
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.
<span>Igneous
rocks are those rocks that were formed through cooling and solidifying the
molten materials. The best example for igneous rock is solid volcanic java.
Lava are liquid that comes from a volcano, but once it is dried and solidify,
it becomes a rock and called igneous rock.
Another example is the granite and basalt. And according to research igneous
rock comes from the latin word ignis which means fire. Thus this says it all.
From a liquid becomes a rock.
</span>
Physical change: a change in which no new substances are formed. the form of the substance is changed but not it's chemical composition (ice melting, bread toasting)
chemical change: any change that results in the formation of new chemical substances. this type of change modifies molecules and atoms by making and breaking the bonds between atoms! (iron rusting, gas burning)
so basically a physical change just changes the appearance of a substance, but a chemical change changes the makeup on a molecular level. i hope this helps you out!
