Basically all it is a nucleus splitting into smaller fragments and these fragments are almost equal to half of the original mass
Answer:
1.78 × 10⁹ μg
Explanation:
We have to convert 1.78 kg to μg.
Step 1: Convert 1.78 kilograms to grams
We will use the conversion factor 1 kg = 10³ g.
1.78 kg × 10³ g/1 kg = 1.78 × 10³ g
Step 2: Convert 1.78 × 10³ grams to micrograms
We will use the conversion factor 1 g = 10⁶ μg.
1.78 × 10³ g × 10⁶ μg/1 g = 1.78 × 10⁹ μg
A is obviously out because it leads to a volume of 125.0 milliliters of the new solution and gives you a lower concentration than you were aiming for.
D is out because you are adding 75 milliliters of the stock solution, so your concentration would be too high. You only need 25.0 milometers of stock solution per 100 milliliters of the new solution.
C is also out because it leads to 50.0 milliliters stock solution per 100 milliliters of the new solution and hence the wrong concentration.
B is by default the correct answer. It also details the correct technique. First you add the stock solution (This you know from your calculations to be 25 milliliters.) then you add the water up to the volume you needed. (Because the calculations only tell you the total volume of water not what you need to add) You also add the water last so you can rinse the neck of the flask to make sure you also get all the stock solution residue into the stock solution.
I would add the final step of stirring, but B is the only answer that can be correct.
The balanced equation for the acid base reaction is as follows
NaOH + HCl ---> NaCl + H₂O
stoichiometry of NaOH to HCl is 1:1
the number of NaOH moles reacted - 0.200 mol/L x 0.0250 L = 0.005 mol
according to molar ratio
number of NaOH moles reacted = number of HCl moles reacted
therefore number of HCl moles - 0.005 mol
volume of 30.0 mL contains 0.005 mol
therefore 1000 mL contains - 0.005 mol / 0.030 L = 0.167 M
concentration of HCl is 0.167 M
