Answer: (3) silicon
Explanation:
Element is a pure substance which is composed of atoms of similar elements.It can not be decomposed into simpler constituents using chemical reactions.Example: Silicon (Si)
Compound is a pure substance which is made from atoms of different elements combined together in a fixed ratio by mass.It can be decomposed into simpler constituents using chemical reactions. Example: ethane
, propanone
and water 
C) Milk boils at about 212°F (100°C).
I don't know if you didn't gave a picture choice or if i didn't get the picture.
But lets call this atom A. Electron dot formula doesn't require Neutron and Protons, its main concern is valance elections.
So atom A has 5 electrons which means 2,3 it has 3 valance electrons. Its dot formula will become
:A.
I hope this helped.
3 mol H₂ → 2 mol NH₃
5 mol H₂ → x mol NH₃
x=2*5.0/3=3.3
n(NH₃)=3.3 mol
One aluminum atom will cost 0.84 × 10⁻²³ cents.
Explanation:
Aluminium costs 85 cents per 453.592 grams.
number of moles = mass / atomic weight
number of moles of aluminium = 453.592 / 27 = 16.8 moles
To calculate the number of aluminum atoms we use the Avogadro's number:
if 1 mole of aluminum contains 6.022 × 10²³ aluminum atoms
then 16.8 moles of aluminum contains X aluminum atoms
X = (16.8 × 6.022 × 10²³) / 1 = 101.17 × 10²³ aluminum atoms
Now, taking in account the aluminium price, we devise the following reasoning:
if 101.17 × 10²³ aluminum atoms costs 85 cents
then 1 aluminum atom costs Y cents
Y = (1 × 85) / (101.17 × 10²³) = 0.84 × 10⁻²³ cents
Learn more about:
Avogadro's number
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