Answer:
0.5M
Explanation:
The equation for molarity is:
- M =
; where the "M" stands for molarity, the "mol" stands for moles of solute and the "liters" means the volume in liters of solution.
We are given that there are:
- 1.80 moles of NaCl (the moles of solute)
- 3.60 Liters of solution (the volume in liters of solution)
Now we just plug those numbers into the formula and get our answer:
- M=
= 0.5M
After doing the math and dividing the moles of solute by the liters of solution, we get that the molarity of the solution is 0.5M.
Answer:
= 72900 years
Explanation:
- The half-life is the time taken by a radioactive material to decay by half the original amount.
- The half-life of plutonium-239 is 24300 years which means it takes 24300 years to decay by half the original amount.
To calculate the time taken for a mass of 8 kg to decay to 1 kg we use;
New mass = Original mass x (1/2) ^n, where n is the number of half-lives
Therefore;
1 kg = 8 kg × (1/2)^n
1/8 = (1/2)^n
solving for n;
n =3
Therefore;
Time = 3 × 24300 years
= 72900 years
It will, therefore, take 72900 years for 8 kg of plutonium-239 to decay to 1 kg.
Answer:
The minimum resistance is 25 ohms.
Explanation:
Resistance of each resistor is 100 ohms. When resistors are connected in parallel, the equivalent resistance is lowest. For parallel combination, the equivalent resistance is given by :
Here, all resistors are 100 ohms. So,
So, the minimum resistance is 25 ohms.
Answer:
Approximately 
.
Explanation:
Note that both figures in the question come with four significant figures. Therefore, the answer should also be rounded to four significant figures. Intermediate results should have more significant figures than that.
<h3>Formula mass of strontium hydroxide</h3>
Look up the relative atomic mass of 
, 
, and 
on a modern periodic table. Keep at least four significant figures in each of these atomic mass data.
Calculate the formula mass of 
:
.
<h3>Number of moles of strontium hydroxide in the solution</h3>
means that each mole of formula units have a mass of 
.
The question states that there are 
of in this solution.
How many moles of formula units would that be?
.
<h3>Molarity of this strontium hydroxide solution</h3>
There are 
of formula units in this 
solution. Convert the unit of volume to liter:
.
The molarity of a solution measures its molar concentration. For this solution:
.
(Rounded to four significant figures.)
