Answer:
The concentration of this solution in units of pounds per gallon is 
Explanation:
Units of measurement are established models for measuring different quantities. The conversion of units is the transformation of a quantity, expressed in a certain unit of measure, into an equivalent one, which may or may not be of the same system of units.
In this case, the conversion of units is carried out knowing that 1 μg are equal to 2.205*10⁻⁹ Lb and 1 mL equals 0.00022 Gallons. So

If 1 μg equals 2.205*10⁻⁹ lb, 2.77 μg how many lb equals?

lb=6.10785*10⁻⁹
So, 2.77 μg= 6.10785*10⁻⁹ lb
Then:

You get:

<u><em>The concentration of this solution in units of pounds per gallon is </em></u>
<u><em></em></u>
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
.
Al:ch2 an molar ratio.
2:3 and an x. X is 30. 20/2 = 10 so an answer is
45/3 = 15. Both ratios are used
45 - 30 = 15 CL2 left.
Your Welcome :)
Answer:

Explanation:
Hello!
In this case, since the molarity of a solution is computed by dividing the moles of solute by the volume of solution in liters, we first need to compute the moles of solute knowing that the molar mass of calcium hydroxide is 74.1 g/mol as follows:

Next, since the 100-mL solution is also expressed in liters by 0.100 L, we directly compute the molarity as shown below:

Which is expressed in molar units that are mol/L.
Best regards!
CaI₂ + Hg(NO₃)₂ --------->HgI₂ + Ca(NO3)2
2Al + 3Cl₂ --------->2AlCl3
Ag + HCl ------->AgCl + H2
C2H2 + 5O2 --------> 4CO2 + 2H2O
MgCl₂ --------->Mg + Cl2