The idea here is that you need to figure out how many moles of magnesium chloride,
MgCl
2
, you need to have in the target solution, then use this value to determine what volume of the stock solution would contain this many moles.
As you know, molarity is defined as the number of moles of solute, which in your case is magnesium chloride, divided by liters of solution.
c
=
n
V
So, how many moles of magnesium chloride must be present in the target solution?
c
=
n
V
⇒
n
=
c
⋅
V
n
=
0.158 M
⋅
250.0
⋅
10
−
3
L
=
0.0395 moles MgCl
2
Now determine what volume of the target solution would contain this many moles of magnesium chloride
c
=
n
V
⇒
V
=
n
c
V
=
0.0395
moles
3.15
moles
L
=
0.01254 L
Rounded to three sig figs and expressed in mililiters, the volume will be
V
=
12.5 mL
So, to prepare your target solution, use a
12.5-mL
sample of the stock solution and add enough water to make the volume of the total solution equal to
250.0 mL
.
This is equivalent to diluting the
12.5-mL
sample of the stock solution by a dilution factor of
20
.
Answer:
because the tectonic plates move 4 inches per year.
Explanation:
Answer:
Vestigial Structures
Explanation:
Structures that were needed for an organism's ancestor, but no longer required for survival for the current organism. We needed our wisdom teeth and appendix in order to eat tougher foods, but now we do not need those to survive. But, we still have them.
Answer:
B = the number of protons
Explanation:
The atom of every elements differ from each other because of number of protons they have.
Every atom consist of neutron, proton and electron. Protons and neutrons are present with in nucleus while the electrons are present out side the nucleus.
All these three subatomic particles construct an atom. A neutral atom have equal number of proton and electron.
The number of neutrons may be same but every atom have different number of protons.
Neutron and proton are present inside the nucleus. Proton has positive charge while neutron is electrically neutral. Proton is discovered by Rutherford while neutron is discovered by James Chadwick in 1932.
Symbol of proton= P+
Symbol of neutron= n0
Mass of proton=1.672623×10-27 Kg
Mass of neutron=1.674929×10-27 Kg
Answer:
Points of acceleration:
1. When female bear goes quickly
2. After becoming tired, when she becomes slow
3. When she changes direction from east to north
4.When she slows down when she reaches the river bed
5. When she turns around
6.When she increases speed to travel southwest to return home
7. When she comes to a stop at home
Explanation:
1. When she is going quickly she is increasing her velocity thus positively accelerating
2. When she becomes slow, she is having negative acceleration.
3. When there is a change in direction of velocity there is an acceleration.
4. Again negative acceleration when she comes to a stop at the river bed
5. Turning around to the southwest direction requires acceleration
6. To increase the velocity to reach home, positive acceleration
7. To decrease the velocity to stop upon reaching home, negative acceleration
