Answer:
A device that does work with only one movement and changes the size or direction of a force is a simple machine.
Explanation:
- For applying force, any used basic mechanical devices are simple machines.
- Simple machine changes the direction as well as the amplitude of the applied force i.e. we can increase or decrease the magnitude of the force.
- A simple machine is the most basic mechanism to use the force as we need in big mechanical machines.
- Some of the examples of simple machines are inclined plane, lever, wedge, wheel and axle, pulley, and screw.
4
N
a
+
O
2
→
2
N
a
2
O
.
By the stoichiometry of this reaction if 5 mol natrium react, then 2.5 mol
N
a
2
O
should result.
Explanation:
The molecular mass of natrium oxide is
61.98
g
⋅
m
o
l
−
1
. If
5
m
o
l
natrium react, then
5
2
m
o
l
×
61.98
g
⋅
m
o
l
−
1
=
154.95
g
natrium oxide should result.
So what have I done here? First, I had a balanced chemical equation (this is the important step; is it balanced?). Then I used the stoichiometry to get the molar quantity of product, and converted this molar quantity to mass. If this is not clear, I am willing to have another go
The subscript 2 indicate that there are two atoms of chlorine in the compound.
<u><em> Explanation</em></u>
Subscript in the chemical formula indicate the number of atoms of the element immediately before the subscript.
In MgCl₂ there are two(2) atoms of chlorine since Subscript 2 is immediately after chlorine.
Elements that have six electrons in the highest-energy p sublevel in their ground state are called the noble gases or inert gases. The six noble gases that occur naturally are helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and the radioactive radon (Rn).
