Answer:
3.29 M
Explanation:
Molarity refers to the molar concentration of a solution and it can be calculated using the formula below:
Molarity (M) = number of moles (n) ÷ volume (V)
According to this question, the mass of HCl was given to be 60.4 grams and the volume of water as 505 mL.
Using mole = mass/molar mass to convert mass of HCl to moles
Molar mass of HCl = 1.0079 + 35.453 = 36.4609g/mol
mole = 60.4g ÷ 36.4609g/mol
mole = 1.66mol
Volume of water = 505mL = 505/1000 = 0.505L
Molarity, M = 1.66 ÷ 0.505
Molarity of HCl solution = 3.29 M
25 milliliters are required
Answer:
4.375 milligram
Explanation:
Applying,
A = A'(2ᵃ/ⁿ)............. Equation 1
Where A = original amount of actinium-228, A' = amount of actinium-228 left after decay, a = Total time, n = half life
make A' the subject of the equation
A' = A/(2ᵃ/ⁿ)........... Equation 2
From the question,
Given: A = 70 milligram, a = 24.52 hours, n = 6.13 hours
Substitute these values into equation 2
A' = 70/(2²⁴°⁵²/⁶°¹³)
A' = 70/(2⁴)
A' = 70/16
A' = 4.375 milligram
Answer:
69,632 grams
explanation
number of molecules =mass\molemass
nh3 14 +2×3=20
3.4×1024=m/20
cross multiply
grams =69,632